Scholars@Duke
Robert Kielb

Robert Kielb

Professor of the Practice Emeritus in the Thomas Lord Department of Mechanical Engineering and Materials Science
Thomas Lord Department of Mechanical Engineering and Materials Science
rkielb@duke.edu
179 Hudson Hall, Box 90300, Durham, NC 27708-0300
179 Hudson Hall, Box 90300, Durham, NC 27708

Selected Publications

Optical measurement and visualization of transonic airflow in a compressor blade cascade

Journal Article Journal of Visualization · June 1, 2023 The paper deals with optical measurements of transonic flow past a five-blade compressor blade cascade. The middle blade of this cascade can be set to different incidence angles simulating its torsional deformation. Classical optical methods (shadowgraphy, ... Full text Cite

Effect of System Mode and Structural Damping Perturbation on the Mistuned Forced Response and Aerodynamic Damping of Embedded Compressor Rotors

Journal Article Journal of Engineering for Gas Turbines and Power · May 1, 2023 This paper is a continuation of previous papers by the authors that focuses on predicting the mistuned embedded rotor blade forced response. The compressor under consideration is a part of a 3.5stage rig located at Purdue University. Previously, the curren ... Full text Cite

Forced Response Induced by Low Engine Order Under Circumferential Inlet Distortions With Different Extents

Journal Article Journal of Turbomachinery · April 1, 2023 Boundary-layer ingestion systems have the potential to improve propulsion efficiency using fluid with lower momentum near the airframe. However, they also bring variations in the velocity and total pressure, leading to a complex distortion of the flow at t ... Full text Cite

A Fluid-Structure Interaction Tool Using a Van der Pol-Based Reduced-Order Model for Buffet and Nonsynchronous Vibrations

Journal Article Journal of Turbomachinery · January 1, 2023 This paper builds upon a two-degree-of-freedom Van der Pol oscillator-based reducedorder model for studying the mechanisms around nonsynchronous vibrations (NSV) in turbomachinery. One degree tracks the fluid motion utilizing a combination of a traditional ... Full text Cite

Improved strain-energy based mistuning models Part I: Motivation, Approach, and Understanding

Conference Proceedings of the ASME Turbo Expo · January 1, 2023 One of the grand challenges in turbomachinery forced response is accurately predicting individual blade responses in a system. This paper helps address these challenges and describes an improved FMM model for computing the mistuned forced response of an em ... Full text Cite

UNSTEADY PRESSURES DURING FREQUENCY LOCK-IN OF A CYLINDER EXPERIENCING NON-SYNCHRONOUS VIBRATIONS

Conference Proceedings of the ASME Turbo Expo · January 1, 2023 When an unsteady aerodynamic instability coalesces with a natural mode of vibration, Non-Synchronous Vibrations (NSV) can occur. Often in turbomachinery, vortex shedding, or tip gap flow causes frequency lock-in to the compressor or turbine blade bending o ... Full text Cite

Extending a Van Der Pol-Based Reduced-Order Model for Fluid-Structure Interaction Applied to Non-Synchronous Vibrations in Turbomachinery

Journal Article Journal of Turbomachinery · March 1, 2022 This paper expands upon a multi-degree-of-freedom, Van der Pol oscillator used to model buffet and nonsynchronous vibrations (NSV) in turbines. Two degrees-of-freedom are used, a fluid tracking variable incorporating a Van der Pol oscillator and a classic ... Full text Cite

Unsteady Pressure Analysis of an Oscillating Cylinder Exhibiting Non-Synchronous Vibrations

Conference AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 · January 1, 2022 When an unsteady aerodynamic instability interacts with the natural modes of vibration of a rigid body, lies a phenomenon known as Non-Synchronous Vibrations (NSV), often referred to as Vortex-Induced Vibrations (VIV). These vibrations cause blade failure ... Full text Cite

Unsteady Pressures Analysis of an Oscillating Airfoil Exhibiting Nonsynchronous Vibrations as Applied to Turbomachinery

Conference AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 · January 1, 2022 When an unsteady aerodynamic instability interacts with the natural modes of vibration of a rigid body, lies a phenomenon known as Non-Synchronous Vibrations (NSV), also known as Vortex-Induced Vibrations (VIV). These vibrations cause blade failure in jet ... Full text Cite

AN IMPROVED PRELIMINARY DESIGN TOOL FOR TURBOMACHINERY BLADES USING VAN DER POL BASED REDUCED-ORDER MODEL FOR NON-SYNCHRONOUS VIBRATIONS

Conference Proceedings of the ASME Turbo Expo · January 1, 2022 Starting from an oscillating cylinder, this paper navigates the shift of a Van der Pol based Reduced-Order Model from that simple case to airfoil and turbomachinery blade. The structure will be free to vibrate under the influence of a von Karman vortex str ... Full text Cite

Impact of upstream and downstream excitation and multi-row interaction on the mistuned forced response behavior of an embedded compressor rotor: Higher-order mode Aeromechanics

Conference Proceedings of the ASME Turbo Expo · January 1, 2022 The current papers discuss the impact of separating the upstream and downstream forcing function contributions in an embedded compressor rotor. Previously, the authors have discussed separating the influence at a torsional mode crossing, and this paper exp ... Full text Cite

A FLUID-STRUCTURE INTERACTION TOOL USING A VAN DER POL BASED REDUCED-ORDER MODEL FOR BUFFET AND NON-SYNCHRONOUS VIBRATIONS

Conference Proceedings of the ASME Turbo Expo · January 1, 2022 This paper builds upon a two-degree-of-freedom Van der Pol oscillator based Reduced-Order Model for studying the mechanisms around Non-Synchronous Vibrations (NSV) in turbomachinery. One degree tracks the fluid motion utilizing a combination of a tradition ... Full text Cite

Effect of system mode and structural damping perturbation on the mistuned forced response and aerodynamic damping of embedded compressor rotors

Conference Proceedings of the ASME Turbo Expo · January 1, 2022 This paper is a continuation of previous papers by the authors that focuses on predicting the mistuned embedded rotor blade forced response. The compressor under consideration is a part of a 3.5stage rig located at Purdue University. Previously, the curren ... Full text Cite

Impact Of Aerodynamic Asymmetry on The Embedded Rotor Forcing and Mistuned Blade Response

Conference Proceedings of the ASME Turbo Expo · January 1, 2022 This paper continues previous research by the current authors in a series of papers describing the impact of multi-row interaction on the forced response behavior of embedded compressor rotors. Specifically, this work dives into an aspect of the embedded r ... Full text Cite

Mistuned forced response sensitivity of an embedded compressor rotor: Effect of sideband travelling wave excitations

Conference AIAA Scitech 2021 Forum · January 1, 2021 This paper describes the aeromechanical aspects of forced response analysis on a 3.5 stage axial compressor. Mistuning is prominent in gas turbine engines as a result of wear and tear of blades, manufacturing variations etc. In a couple of their earlier pa ... Cite

Separation of wake and potential field excitations in an embedded compressor rotor: Impact of wave reflections and mistuning on forced response

Conference AIAA Scitech 2021 Forum · January 1, 2021 This paper provides a summary of an embedded rotor mistuned forced response investigation. Forced response aeromechanics is one of the grand challenge topics, which has received much attention in literature. The current paper analyzes an embedded rotor fro ... Full text Cite

Extending a van der pol based reduced-order model for fluid-structure interaction applied to non-synchronous vibrations in turbomachinery

Conference Proceedings of the ASME Turbo Expo · January 1, 2021 This paper expands upon a multi-degree-of-freedom, Van der Pol oscillator used to model buffet and Nonsynchronous Vibrations (NSV) in turbines. Two degreesof-freedom are used, a fluid tracking variable incorporating a Van der Pol oscillator and a classic s ... Full text Cite

Influence of stator hub cavities on the forced response behaviour of an embedded compressor rotor

Conference Proceedings of the ASME Turbo Expo · January 1, 2021 This paper focuses on the impact of hub labyrinth seal leakage flows on the aeromechanical behavior of an embedded compressor rotor. End wall flows are critical in determining the performance of gas turbine engine compressors, particularly the hub leakage ... Full text Cite

Influence of disc modes and sideband excitations on the mistuned forced response behaviour of an embedded compressor rotor

Conference Proceedings of the ASME Turbo Expo · January 1, 2021 This paper focusses on predicting the mistuned forced response behavior of an embedded compressor rotor blade row in a 3.5 stage axial compressor. The authors in previous papers studied the multi-row influence on the forcing function for multiple operating ... Full text Cite

Impact of multi-row aerodynamic interaction on the forced response behaviour of an embedded compressor rotor

Conference Proceedings of the ASME Turbo Expo · January 1, 2020 This paper focuses on the impact of multi-row interaction on the forced response behavior of an embedded compressor rotor at higher order modes. The authors in previous papers have discussed about the multi-row influence at the torsional mode resonant cros ... Full text Cite

Separation of up and Downstream Forced Response Excitations of an Embedded Compressor Rotor

Journal Article Journal of Turbomachinery · September 1, 2019 The aerodynamic interaction of upstream and downstream blade rows can have a significant impact on the forced response of the compressor. Previously, the authors carried out the forced response analysis of a three-row stator-rotor-stator (S1-R2-S2) configu ... Full text Cite

A Mistuned Forced Response Analysis of an Embedded Compressor Blisk Using a Reduced-Order Model

Journal Article Journal of Engineering for Gas Turbines and Power · March 1, 2019 Accuracy when assessing mistuned forced response analyses is still a major concern. Since a fully coupled analysis is still very computational expensive, several simplifications and reduced-order models (ROMs) are carried out. The use of a reduction method ... Full text Cite

Nonlinear interaction of a flutter induced limit cycle oscillation of a cantilevered wing with a forced gust excitation

Conference AIAA Scitech 2019 Forum · January 1, 2019 Within the framework of a linear mode (physical or theoretical/computational) the dynamic instability (flutter) of the system and the forced response of the system (due to gust excitation, for example) can be considered separately and there is no interacti ... Full text Cite

Mistuned higher-order mode forced response of an embedded compressor rotor-Part II: Mistuned forced response prediction

Journal Article Journal of Turbomachinery · March 1, 2018 This paper is the second part of a two-part paper that presents a comprehensive study of the higher-order mode (HOM) mistuned forced response of an embedded rotor blisk in a multistage axial research compressor. The resonant response of the second-stage ro ... Full text Cite

A mistuned forced response analysis of an embedded compressor blisk using a reduced order model

Conference Proceedings of the ASME Turbo Expo · January 1, 2018 Accuracy when assessing mistuned forced response analyses is still a mayor concern. Since a full coupled analysis is still very computational expensive, several simplifications and reduced order models are carried out. The use of a reduction method, the as ... Full text Cite

Influence of rotor-stator interaction and reflecting boundary conditions on compressor forced response

Conference Proceedings of the ASME Turbo Expo · January 1, 2018 This paper focuses on the rotor forced response behavior in a 3.5-stage compressor rig. The aim is to provide an accurate prediction of forced response with the less computational effort. Previous research indicates that by reducing the computation domain ... Full text Cite

Influence of the tip clearance on a compressor blade aerodynamic damping

Journal Article Journal of Propulsion and Power · January 1, 2017 The flutter CFD calculations conducted in industry generally use a single-row, single-passage approach with a minimum of detailing to reduce the computational time as much as possible. The question arises of what level of detailing is necessary for accurat ... Full text Cite

TIP clearance influence on aerodynamic damping maps

Conference 12th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2017 · January 1, 2017 Copyright © by the Authors. This paper aims to investigate the influence of tip clearance on aerodynamic damping maps of an oscillating low pressure turbine (LPT) unshrouded blade row. Full-scale time-marching RANS CFD simulations in ANSYS CFX® v.16.2 empl ... Cite

System eigenvalue identification of mistuned bladed disks using least-squares complex frequency-domain method

Conference Proceedings of the ASME Turbo Expo · January 1, 2017 This paper presents the results from a research effort on eigenvalue identification of mistuned bladed rotor systems using the Least-Squares Complex Frequency-Domain (LSCF) modal parameter estimator. The LSCF models the frequency response function (FRF) ob ... Full text Cite

Thermodynamic Analysis of Post-combustion Inertial CO2 Extraction System

Conference Energy Procedia · January 1, 2017 The Inertial CO2 Extraction System (ICES) represents a novel method of capturing CO2 from flue gas. ICES makes use of the cooling effect of supersonic expansion to cool the flue gas stream, causing CO2 in the flue gas to change phase to form a solid that c ... Full text Cite

Mistuned higher-order mode forced response of an embedded compressor rotor, part II: Mistuned forced response prediction

Conference Proceedings of the ASME Turbo Expo · January 1, 2017 This paper is the second part of a two-part paper that presents a comprehensive study of the higher-order mode mistuned forced response of an embedded rotor blisk in a multi-stage axial research compressor. The resonant response of the second-stage rotor ( ... Full text Cite

Mistuned higher-order mode forced response of an embedded compressor rotor, part I: Steady and unsteady aerodynamics

Conference Proceedings of the ASME Turbo Expo · January 1, 2017 This paper is the first part of a two-part paper that presents a comprehensive study of the higher-order mode mistuned forced response of an embedded rotor blisk in a multistage axial research compressor. The resonant response of the second-stage rotor (R2 ... Full text Cite

Forcing superposition and decomposition of an embedded compressor rotor

Conference Proceedings of the ASME Turbo Expo · January 1, 2017 This paper investigates superposition and decomposition methods when determining the forcing function on an embedded rotor in a multistage axial compressor. Under investigation is a 3-row stator/rotor/stator configuration where two stators, having the same ... Full text Cite

Interaction of concurrent forced response and flutter phenomena in a compressor stage

Conference Proceedings of the ASME Turbo Expo · January 1, 2017 This paper studies a subsonic compressor case with concurrent forced response and flutter by using the Harmonic Balance method, and was inspired by historical experimental data. Forced response was observed when the rotating speed was approaching a crossin ... Full text Cite

TIP clearance influence on aerodynamic damping maps

Conference 12th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2017 · January 1, 2017 This paper aims to investigate the influence of tip clearance on aerodynamic damping maps of an oscillating low pressure turbine (LPT) unshrouded blade row. Full-scale time-marching RANS CFD simulations in ANSYS CFX® v.16.2 employing models with 0%, 1%, 2% ... Cite

498520 Analysis of post-combustion inertial CO2 extraction system

Conference International Congress on Energy 2017 - Topical Conference at the 2017 AIChE Annual Meeting · January 1, 2017 Cite

TIP clearance influence on aerodynamic damping maps

Conference European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC · January 1, 2017 This paper aims to investigate the influence of tip clearance on aerodynamic damping maps of an oscillating low pressure turbine (LPT) unshrouded blade row. Full-scale time-marching RANS CFD simulations in ANSYS CFX® v.16.2 employing models with 0%, 1%, 2% ... Cite

Mistuned forced response predictions of an embedded rotor in a multistage compressor

Journal Article Journal of Turbomachinery · June 1, 2016 This paper covers a comprehensive forced response analysis conducted on a multistage compressor and compared with the largest forced response experimental data set ever obtained in the field. The steady-state aerodynamic performance and stator wake predict ... Full text Cite

The impact of blade loading and unsteady pressure bifurcations on low-pressure turbine flutter boundaries

Journal Article Journal of Turbomachinery · April 1, 2016 The three major aeroelastic issues in the turbomachinery blades of jet engines and power turbines are forced response, nonsynchronous vibrations, and flutter. Flutter primarily affects high-aspect ratio blades found in the fan, fore high-pressure compresso ... Full text Cite

Forced response sensitivity of a mistuned rotor from an embedded compressor stage

Journal Article Journal of Turbomachinery · March 1, 2016 The frequency mistuning that occurs due to manufacturing variations and wear and tear of the blades has been shown to significantly affect the flutter and forced response behavior of a blade row. While tuned computational fluid dynamics (CFD) analyses are ... Full text Cite

An aeroelastic model for vortex-induced vibrating cylinders subject to frequency lock-in

Journal Article Journal of Fluids and Structures · February 1, 2016 This work presents a novel way to calculate the response amplitude of an elastically supported cylinder experiencing vortex-induced vibrations. The method couples a computational fluid dynamic (CFD) model of the shedding vortex flow to a structural model r ... Full text Cite

Vortex-Induced Vibration and Frequency Lock-In of an Airfoil at High Angles of Attack

Journal Article Journal of Fluids Engineering, Transactions of the ASME · January 1, 2016 Vortex-induced vibration is a fluid instability where vortices due to secondary flows exert a periodic unsteady force on the elastic structure. Under certain circumstances, the shedding frequency can lock into the structure natural frequency and lead to li ... Full text Cite

Shock structure, mode shape, and geometric considerations for low-pressure turbine flutter suppression

Conference Proceedings of the ASME Turbo Expo · January 1, 2016 Modern design principles are pushing for lighter aircraft engines and higher tip Mach numbers in steam turbines. Consequently the loading and shock structures seen on aft stages o low-pressure turbines are evolving at a fast pace. Since flutte is a high ri ... Full text Cite

Developing a reduced-order model of nonsynchronous vibration in turbomachinery using proper-orthogonal decomposition methods

Journal Article Journal of Engineering for Gas Turbines and Power · May 1, 2015 The paper develops a reduced-order model of nonsynchronous vibration (NSV) using proper orthogonal decomposition (POD) methods. The approach was successfully developed and implemented, requiring between two and six POD modes to accurately predict computati ... Full text Cite

The inuence of steady loading parameters on low-pressure turbine flutter

Conference 56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference · January 1, 2015 Aeroelastic utter is a major concern of turbomachinery engineers. As such, this poten- tially catastrophic self-excitation mechanism has been the focus of many research endeavors. While most investigations have concentrated on identifying key correlations ... Cite

Physical understanding and sensitivities of low pressure turbine flutter

Journal Article Journal of Engineering for Gas Turbines and Power · January 1, 2015 Successful, efficient turbine design requires a thorough understanding of the underlying physical phenomena. This paper investigates the flutter phenomenon of low pressure turbine (LPT) blades seen in aircraft engines and power turbines. Computational flui ... Full text Cite

Effects of blade count ratio on aerodynamic forcing and mode excitability

Conference Proceedings of the ASME Turbo Expo · January 1, 2015 The effects of blade count ratio (BCR) on both the steady and unsteady blade loading and the sensitivity of generalized force to a change in mode shape (mode excitability) are studied numerically on two 2D configurations: a subsonic research compressor sta ... Full text Cite

Forced response sensitivity of a mistuned rotor from an embedded compressor stage

Conference Proceedings of the ASME Turbo Expo · January 1, 2015 The frequency mistuning that occurs due to manufacturing variations and wear and tear of the blades can have a significant effect on the flutter and forced response behavior of a blade row. Similarly, asymmetries in the aerodynamic or excitation forces can ... Full text Cite

Design of a single stage turbine for the quantification of aerodynamic damping

Conference Proceedings of the ASME Turbo Expo · January 1, 2015 For an experimental study of aerodynamic damping in an axial low pressure turbine, a single stage subsonic turbine blisk is designed and aerodynamically and aeromechanically assessed. The design goals are a low aerodynamic damping, to allow a long ring dow ... Full text Cite

The impact of blade loading and unsteady pressure bifurcations on low-pressure turbine flutter boundaries

Conference Proceedings of the ASME Turbo Expo · January 1, 2015 The three major aeroelastic issues in the turbomachinery blades of jet engines and power turbines are forced response, non-synchronous vibrations, and flutter. Flutter primarily affects high-aspect ratio blades found in the fan, fore high-pressure compress ... Full text Cite

Vortex-induced vibration and frequency lock-in of an airfoil at high angles of attack

Conference Proceedings of the ASME Turbo Expo · January 1, 2014 Vortex-induced vibration is a fluid instability present in many areas, including offshore platforms, wind turbines, and turbomachinery. The vortices due to secondary flows exert an periodic unsteady force on the elastic structure, leading to potentially da ... Full text Cite

Developing a reduced-order model of non-synchronous vibration in turbomachinery using proper-orthogonal decomposition methods

Conference Proceedings of the ASME Turbo Expo · January 1, 2014 The paper develops a reduced-order model of nonsynchronous vibration (NSV) using proper orthogonal decomposition (POD) methods. The approach was successfully developed and implemented, requiring between two and six POD modes to accurately predict CFD solut ... Full text Cite

Physical understanding and sensitivities of lpt flutter

Conference Proceedings of the ASME Turbo Expo · January 1, 2014 Successful, efficient turbine design requires a thorough understanding of the underlying physical phenomena. This paper investigates the flutter phenomenon of low pressure turbine (LPT) blades seen in aircraft engines and power turbines. CFD analysis will ... Full text Cite

A van der pol based reduced-order model for non-synchronous vibration (NSV) in turbomachinery

Conference Proceedings of the ASME Turbo Expo · January 1, 2013 This paper demonstrates the potential of using a multidegree- of-freedom, traditional van der Pol oscillator to model non-synchronous vibration (NSV) in turbomachinery. It is shown that the two main characteristics of NSV are captured by the reduced-order, ... Full text Cite

The effect of aerodynamic asymmetries on turbomachinery flutter

Journal Article Journal of Fluids and Structures · January 1, 2013 In this paper, the effect of aerodynamic asymmetries on the flutter characteristics of turbomachinery blades is investigated. Specifically, the present method is used to study the effect of leading edge blending in loaded and unloaded rotors. The unsteady ... Full text Cite

Developing a reduced-order model to understand nonsynchronous vibration (NSV) in turbomachinery

Conference Proceedings of the ASME Turbo Expo · January 1, 2012 This paper demonstrates the potential of using a multidegree- of-freedom, traditional van der Pol oscillator to model Non-Synchronous Vibration (NSV) in turbomachinery. It is shown that the two main characteristics of NSV are captured by the reduced-order, ... Full text Cite

Nonlinear flutter in fan stator vanes with time dependent fixity

Journal Article Journal of Turbomachinery · June 23, 2011 A new mechanism for fan stator vane failure in turbofan engines at high speed and high loading has been identified and reported in this paper. Highly destructive vane failures have been encountered at Honeywell in a development fan with composite stator va ... Full text Cite

Non-linear flutter in fan stator vanes with time dependent fixity

Journal Article Proceedings of the ASME Turbo Expo · December 1, 2010 A new mechanism for fan stator vane failure in turbofan engines at high speed and high loading has been identified and reported in this paper. Highly destructive vane failures have been encountered at Honeywell in one of the development fans with composite ... Full text Cite

Harmonic balance analysis of blade row interactions in a transonic compressor

Journal Article Journal of Propulsion and Power · January 1, 2010 In this paper we apply the harmonic balance technique to analyze an inlet guide vane and rotor interaction problem, and compare the computed flow solutions to existing experimental data. The computed results, which compare well with the experimental data, ... Full text Cite

Forced response analysis of aerodynamically asymmetric cascades

Conference 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit · January 1, 2010 The effect of aerodynamic asymmetries on forced response characteristics of cascades is investigated. Specifically, the present method is used to study the effect of leading edge blending in loaded rotors. The unsteady aerodynamic response of the blades to ... Full text Cite

Preliminary flutter design method for supersonic low pressure turbines

Journal Article Proceedings of the ASME Turbo Expo · December 1, 2009 The "Tie-Dye" (TD) method is a well-known preliminary flutter design method for subsonic low pressure turbine (LPT) blades. In this paper, a study of 2D mode shape sensitivity using the TD-method for supersonic exit Mach numbers is presented. Using a harmo ... Full text Cite

The Effects of aerodynamic asymmetric perturbations on forced response of bladed disks

Journal Article Journal of Turbomachinery · October 1, 2009 Most of the existing mistuning research assumes that the aerodynamic forces on each of the blades are identical except for an interblade phase angle shift. In reality, blades also undergo asymmetric steady and unsteady aerodynamic forces due to manufacturi ... Full text Cite

Application of enforced motion to study 2-D cascade lock-in effect

Conference 47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition · January 1, 2009 The vortex lock-in effect has been well-studied for an oscillating cylinder and numerous experimental and computational data are available. However, only recently has this phenomenon been observed for two-dimensional isolated airfoils as well as turbine ca ... Full text Cite

Harmonic balance analysis of forced response in a transonic compressor

Conference 47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition · January 1, 2009 A harmonic balance technique for the analysis of nonlinear forced response phenomenon in a two-row transonic compressor is presented. Using the present approach, each blade row is modeled using a computational grid spanning a single blade passage regardles ... Full text Cite

The effect of aerodynamic asymmetries on turbomachinery flutter

Conference 47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition · January 1, 2009 In this paper, the effect of aerodynamic asymmetries on the flutter characteristics of turbomachinery blades is investigated. Specifically, the present method is used to study the effect of leading edge blending in loaded and unloaded rotors. The unsteady ... Full text Cite

Efficient design method for non-synchronous vibrations using enforced motion

Conference Proceedings of the ASME Turbo Expo · December 1, 2008 This paper presents the results of a new enforced motion method using harmonic balance computational fluid dynamics (CFD) analysis to design for NSV. Currently, most researchers employ a time domain CFD technique to directly find the frequency of the under ... Full text Cite

The effects of aerodynamic asymmetric perturbations on forced response of bladed disks

Conference Proceedings of the ASME Turbo Expo · December 1, 2008 Most of the existing mistuning research assumes that the aerodynamic forces on each of the blades are identical except for an interblade phase angle shift. In reality, blades also undergo asymmetric steady and unsteady aerodynamic forces due to manufacturi ... Full text Cite

Aerodynamic asymmetry analysis of unsteady flows in turbomachinery

Conference Proceedings of the ASME Turbo Expo · December 1, 2008 A nonlinear harmonic balance technique for the analysis of aerodynamic asymmetry of unsteady flows in turboma-chinery is presented. The present method uses a mixed time-domain/frequency-domain approach that allows one to compute the unsteady aerodynamic re ... Full text Cite

Reduced order models in unsteady aerodynamic models, aeroelasticity and molecular dynamics

Conference ICAS Secretariat - 26th Congress of International Council of the Aeronautical Sciences 2008, ICAS 2008 · December 1, 2008 The state of reduced order modeling of unsteady aerodynamic flows for the efficient calculation of fluid-structure interaction (aeroelasticity) is discussed as well as very recent work on olecular dynamics simulations. Starting with either a time domain or ... Cite

Aerodynamic Asymmetry Analysis of Unsteady Flows in Turbomachinery

Journal Article Journal of Turbomachinery · 2008 Cite

A new solution method for unsteady flows around oscillating bluff bodies

Journal Article Solid Mechanics and its Applications · January 1, 2008 Full text Cite

The effect of unsteady aerodynamic asymmetric perturbations on flutter

Conference Proceedings of the ASME Turbo Expo · January 1, 2007 Nearly all turbomachinery aeroelastic analyses assume that the blades are "tuned" aerodynamically. That is, all blades experience identical steady and unsteady loads (except for an interblade phase shift). This paper presents the results of a perturbations ... Full text Cite

Probabilistic flutter analysis of a mistuned bladed disk

Conference Proceedings of the ASME Turbo Expo · 2006 This paper presents the results of a probabilistic flutter study of a mistuned bladed disk using a high fidelity model including both structural and aerodynamic coupling. The approach used in this paper is relatively fast because it does not require any ad ... Cite

Modeling cylinder flow vortex shedding with enforced motion using a harmonic balance approach

Conference Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference · January 1, 2006 In recent years, new aeromechanical problems have been encountered in turbomachinery. In particular, non-synchronous vibrations (NSV) in blades have been observed by engine companies and occur as a result of flow instabilities. As a first step towards bett ... Full text Cite

Reduced order unsteady aerodynamic models and aeroelasticity

Conference 12th International Congress on Sound and Vibration 2005, ICSV 2005 · December 1, 2005 The state of reduced order modeling of unsteady aerodynamic flows for the efficient calculation of fluid-structure interaction (aeroelasticity) is discussed. Reduced order modeling is a set of conceptually novel and computationally efficient techniques for ... Cite

Computational models for nonlinear aeroelasticity

Conference 43rd AIAA Aerospace Sciences Meeting and Exhibit - Meeting Papers · January 1, 2005 Two distinctly different reduced-order models are formulated for fully nonlinear aeroelastic systems. The first is based on Proper Orthogonal Decomposition (POD). The velocity field is decomposed into a finite number of orthonormal modes, effecting order r ... Full text Cite

Recent advancements in turbomachinery aeroelastic design analysis

Conference 43rd AIAA Aerospace Sciences Meeting and Exhibit - Meeting Papers · January 1, 2005 In this paper, we review some recent developments for computing unsteady aerodynamic loads associated with turbomachinery aeromechanics. In particular, we example the use of frequency domain techniques for computing unsteady flows in turbomachinery. The fr ... Full text Cite

Flutter of low pressure turbine blades with cyclic symmetric modes: A preliminary design method

Journal Article Journal Of Turbomachinery-transactions Of The Asme · April 2004 A current preliminary design method for flutter of low pressure turbine blades and vanes only requires knowledge of the reduced frequency and mode shape (real). However many low pressure turbine (LPT) blade designs include a tip shroud that mechanically co ... Cite

Flutter of mistuned bladed disks and blisks with aerodynamic and FMM structural coupling

Conference Proceedings of the ASME Turbo Expo 2004 · January 1, 2004 This paper presents the initial results from a research effort on blisk and bladed disk mistuning including both structural and aerodynamic coupling. The structural coupling model is based on the Fundamental Mistuning Model (FMM, developed by Feiner & Grif ... Full text Cite

Flutter of low pressure turbine blades with cyclic symmetric modes - A preliminary design method

Conference American Society of Mechanical Engineers, International Gas Turbine Institute, Turbo Expo (Publication) IGTI · December 1, 2003 A current preliminary design method for flutter of low pressure turbine blades and vanes only requires knowledge of the reduced frequency and mode shape (real). However, many low pressure turbine (LPT) blade designs include a tip shroud, that mechanically ... Full text Cite

Effect of sector mode shape variation on the aerodynamic stability of a low-pressure turbine sectored vane

Conference American Society of Mechanical Engineers, International Gas Turbine Institute, Turbo Expo (Publication) IGTI · December 1, 2003 The paper presents a method to investigate the flutter appearance in a cascade, where blades are connected together in a number of identical sectors. The key parameters of the method are vibration amplitudes and mode shapes of the blades belonging to the s ... Full text Cite

Blade excitation by aerodynamic instabilities - A compressor blade study

Conference American Society of Mechanical Engineers, International Gas Turbine Institute, Turbo Expo (Publication) IGTI · 2003 In this paper, we investigate non-synchronous vibrations (NSV) in turbomachinery, an aeromechanic phenomenon in which rotor blades are driven by a fluid dynamic instability. Unlike flutter, a self-excited vibration in which vibrating rotor blades and the r ... Cite

CFD for turbomachinery unsteady flows - An aeroelastic design perspective

Conference 39th Aerospace Sciences Meeting and Exhibit · December 1, 2001 The lecture addresses unsteady flow prediction from the perspective of the aeroelastic blade designer with emphasis on flutter and resonant response. The subjects discussed are the aeroelastic design problem, current state of technology, and future needs. ... Cite

Design method to prevent low pressure turbine blade flutter

Conference American Society of Mechanical Engineers (Paper) · January 1, 1998 A design approach to avoid flutter of low pressure turbine blades in aircraft engines is described. A linearized Euler analysis, previously validated using experimental data, is used for a series of parameter studies. The influence of mode shape and reduce ... Cite

High stability engine control (HISTEC) flight test results

Conference 34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit · January 1, 1998 The High Stability Engine Control (HISTEC) Program, managed and funded by the NASA Lewis Research Center, is a cooperative effort between NASA and Pratt & Whitney (P&W). The program objective is to develop and flight demonstrate an advanced highstability i ... Full text Cite

Advanced damping systems for fan and compressor blisks

Conference 34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit · January 1, 1998 This paper describes a passive damping program for fan and compressor blisks. Specific goals include the design, manufacture and spin test of two passive damping systems to achieve effective magnification factors (Q) of 50 or less for the targeted modes of ... Cite

A design method to prevent low pressure turbine blade flutter

Conference Proceedings of the ASME Turbo Expo · January 1, 1998 A design approach to avoid flutter of low pressure turbine blades in aircraft engines is described. A linearized Euler analysis, previously validated using experimental data, is used for a series of parameter studies. The influence of mode shape and reduce ... Full text Cite

The effect of blade angle design selection on wave-turbine engine performance

Conference ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition, GT 1996 · January 1, 1996 Wave rotors have been investigated over several decades in part due to their potential for increasing the maximum cycle temperature in gas turbine engines via their self-cooling mechanism. Recent activities in this field have centered on the experiments an ... Full text Cite

Effect of blade angle design selection on wave-turbine engine performance

Conference American Society of Mechanical Engineers (Paper) · January 1, 1996 Wave rotors have been investigated over several decades in part due to their potential for increasing the maximum cycle temperature in gas turbine engines via their self-cooling mechanism. Recent activities in this field have centered on the experiments an ... Cite

An analysis system for blade forced response

Journal Article Journal of Turbomachinery · January 1, 1993 A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes and7 or pressure disturbances from adjacent blade rows. The standard method ... Full text Cite

An analysis system for blade forced response

Conference ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition, GT 1992 · January 1, 1992 A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes, and/or pressure disturbances from adjacent blade rows. The standard method ... Full text Cite

An Analysis System for Blade Forced Response

Conference ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition, GT 1992 · January 1, 1992 A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes, and/or pressure disturbances from adjacent blade rows. The standard method ... Full text Cite

An integrated approach for friction damper design

Journal Article Journal of Vibration and Acoustics, Transactions of the ASME · January 1, 1990 A procedure is outlined for determining the optimal design of friction dampers for high-speed turbomachinery blading. The procedure includes: An integration of bench test results with finite-element analysis and a single-mode blade model to ensure accuracy ... Full text Cite

Flutter of a fan blade in supersonic axial flow

Journal Article Journal of Turbomachinery · January 1, 1989 An application of a simple aeroelastic model to an advanced supersonic axial flow fan is presented. Lane’s cascade theory is used to determine the unsteady aerodynamic loads. Parametric studies are performed to determine the effects of mode coupling, Mach ... Full text Cite

FLUTTER OF A FAN BLADE IN SUPERSONIC AXIAL FLOW.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1988 An application of a simple aeroelastic model to an advanced supersonic axial flow fan is presented. Lane's cascade theory is used to determine the unsteady aerodynamic loads. Parametric studies are performed to determine the effects of mode coupling, Mach ... Cite

INTEGRATED APPROACH FOR FRICTION DAMPER DESIGN.

Conference American Society of Mechanical Engineers, Design Engineering Division (Publication) DE · December 1, 1987 A procedure is outlined for determining the optimal design of friction dampers for high speed turbo-machinery blading. The procedure includes: an integration of bench test results with finite element analysis and a single mode blade model to ensure accurac ... Cite

COMPUTER PROGRAM FOR CALCULATING UNSTEADY AERODYNAMIC COEFFICIENTS FOR CASCADES IN SUPERSONIC AXIAL FLOW.

Report · December 1, 1987 Recent interest in supersonic and hypersonic flight has renewed interest in developing propulsion systems which include a supersonic axial flow compressor. An important design consideration for the blades in such a compressor is aeroelastic stability. This ... Cite

MASS BALANCING OF HOLLOW FAN BLADES.

Report · June 1, 1986 This paper uses a typical section model to analytically investigate the effect of mass balancing as applied to hollow, supersonic fan blades. A procedure to determine the best configuration of an internal balancing mass to provide flutter alleviation is de ... Cite

Influence of friction dampers on torsional blade flutter

Journal Article Journal of Engineering for Gas Turbines and Power · January 1, 1986 This paper deals with the stabilizing effects of dry friction on torsional blade flutter. A lumped parameter model with single degree of freedom per blade has been used to represent the rotor stage. The well-known cascade theories for incompressible and su ... Full text Cite

Mass balancing of hollow fan blades

Journal Article Journal of Engineering for Gas Turbines and Power · January 1, 1986 This paper uses a typical section model to investigate analytically the effect of mass balancing as applied to hollow, supersonic fan blades. A procedure to determine the best configuration of an internal balancing mass to provide flutter alleviation is de ... Full text Cite

Dynamic characteristics of an assembly of prop-fan blades

Journal Article Journal of Engineering for Gas Turbines and Power · January 1, 1986 Full text Cite

Mass Balancing of Hollow Fan Blades

Conference Proceedings of the ASME Turbo Expo · January 1, 1986 Tnis paper uses a typical section model to analytically investigate the effect of mass balancing as applied to hollow, supersonic fan blades. A procedure to determine the best configuration of an internal balancing mass to provide flutter alleviation is de ... Full text Cite

JOINT RESEARCH EFFORT ON VIBRATIONS OF TWISTED PLATES. PHASE I: FINAL RESULTS.

Report · September 1, 1985 This publication gives the complete theoretical and experimental results of the first phase of a joint government/industry/university research study on the vibration characteristics of twisted cantilever plates. The study was conducted to generate an exper ... Cite

STRUCTURAL AND AEROELASTIC ANALYSIS OF THE SR-7L PROPFAN.

Report · March 1, 1985 This paper presents a structural and aeroelastic analysis of a large scale advanced turboprop rotor blade. This 8-blade rotor is designed to operate at Mach 0. 8 at an altitude of 35,000 ft. The blades are highly swept and twisted and of spar/shell constru ... Cite

Flutter of swept fan blades

Journal Article Journal of Engineering for Gas Turbines and Power · January 1, 1985 The purpose ofthe research presented in this paper is to study the effect ofsweep on fan blade flutter by applying the analytical methods developed for aeroelastic analysis of advanced turboprops. Two methods are used. The first method utilizes an approxim ... Full text Cite

Vibrations of twisted cantilevered plates-experimental investigation

Journal Article Journal of Engineering for Gas Turbines and Power · January 1, 1985 The experimental portion of a joint government/industry/university research study on the vibrational characteristics of twisted cantilevered plates is presented. The overall purpose of the research study was to assess the capabilities and limitations of ex ... Full text Cite

DYNAMIC CHARACTERISTICS OF AN ASSEMBLY OF PROP-FAN BLADES.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1985 The renewed interest in propeller propulsion is based on large reductions expected in fuel burned and direct operating costs compared to advance turbofan propulsion. Current predictions indicate that a prop-fan (Advanced Propeller) powered 120-passenger ai ... Cite

INFLUENCE OF FRICTION DAMPERS ON TORSIONAL BLADE FLUTTER.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1985 A discussion is presented on the stabilizing effects of dry friction on torsional blade flutter. A lumped parameter model with single degree of freedom per blade has been used to represent the rotor stage. The well-known cascade theories for incompressible ... Cite

Vibration and flutter of mistuned bladed-disk assemblies

Journal Article Journal of Propulsion and Power · January 1, 1985 An analytical model for investigating vibration and flutter of mistuned bladed-disk assemblies is presented. This model accounts for elastic, inertial, and aerodynamic coupling between bending and torsional motions of each individual blade, elastic and ine ... Full text Cite

Vibrations of twisted cantilever plates—a comparison of theoretical results

Journal Article International Journal for Numerical Methods in Engineering · January 1, 1985 Previously published literature shows widely different results for the free vibration frequencies of twisted cantilever plates. Inasmuch as it is important to know the vibration characteristics of turbomachinery blades, which may have considerable twist, i ... Full text Cite

EFFECTS OF WARPING AND PRETWIST ON TORSIONAL VIBRATION OF ROTATING BEAMS.

Conference American Society of Mechanical Engineers (Paper) · December 1, 1984 The effect of pretwist and warping on the torsional vibration of short-aspect-ratio rotating beams is examined for application to the modeling of turbofan, turboprop, and compressor blades. The equations of motion and the associated boundary conditions by ... Cite

Vibrations of twisted cantilevered plates-Summary of previous and current studies

Journal Article Journal of Sound and Vibration · September 22, 1984 This work summarizes a comprehensive study made of the free vibrations of twisted, cantilevered plates of rectangular planform. Numerous theoretical and experimental investigations previously made by others have resulted in frequency results which disagree ... Full text Cite

NONLINEAR DISPLACEMENT ANALYSIS OF ADVANCED PROPELLER STRUCTURES USING NASTRAN.

Report · August 1, 1984 The steady state displacements of a rotating advanced turboprop are computed using the geometrically nonlinear capabilities of COSMIC NASTRAN Rigid Format 4 and MSC NASTRAN Solution 64. A description of the modified Newton-Raphson algorithm used by Solutio ... Cite

LEWIS RESEARCH CENTER SPIN RIG AND ITS USE IN VIBRATION ANALYSIS OF ROTATING SYSTEMS.

Journal Article NASA Technical Paper · May 1, 1984 The Lewis Research Center spin rig was constructed to provide experimental evaluation of analysis methods developed under the NASA Engine Structural Dynamics Program. Rotors up to 51 cm (20in. ) in diameter can be spun to 16,000 rpm up to 51 cm (20 in. ) i ... Cite

FLUTTER OF SWEPT FAN BLADES.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1984 Cite

Effects of warping and pretwist on torsional vibration of rotating beams

Journal Article Journal of Applied Mechanics, Transactions ASME · January 1, 1984 The effect of pretwist and warping on the torsional vibration of short-aspect-ratio rotating beams is examined for application to the modeling ofturbofan, turboprop, and compressor blades. The equations of motion and the associated boundary conditions by u ... Full text Cite

VIBRATIONS OF TWISTED CANTILEVERED PLATES - EXPERIMENTAL INVESTIGATION.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1984 Cite

VIBRATIONS OF TWISTED CANTILEVERED PLATES - EXPERIMENTAL INVESTIGATION.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1984 Cite

Flutter of swept fan blades.

Journal Article · January 1, 1984 The purpose of the research presented in this paper is to study the effect of sweep on fan blade flutter by applying the analytical methods developed for aeroelastic analysis of advanced turboprops. Two methods are used. The first method utilizes an approx ... Cite

Effects of structural coupling on mistimed cascade flutter and response

Journal Article Journal of Engineering for Gas Turbines and Power · January 1, 1984 The effects of structural coupling on mistuned cascade flutter and response are analytically investigated using an extended typical section model. Previous work using two degree of freedom per blade typical section models has included only aerodynamic coup ... Full text Cite

Flutter of swept fan blades.

Journal Article TRANS. ASME J. ENGNG. GAS TURBINES & POWER · January 1, 1984 The effect of sweep on fan blade flutter by applying the analytical methods developed for aeroelastic analysis of advanced turboprops was studied. Two methods are used. The first method utilizes an approximate structural model in which the blade is represe ... Cite

FLUTTER OF SWEPT FAN BLADES.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1984 Cite

FLUTTER OF SWEPT FAN BLADES.

Journal Article NASA Technical Memorandum · January 1, 1984 The purpose of the research presented in this paper is to study the effect of sweep on fan blade flutter by applying the analytical methods developed for aeroelastic analysis of advance turboprops. Two methods are used. The first method utilizes an approxi ... Cite

VIBRATION AND FLUTTER OF MISTUNED BLADED-DISK ASSEMBLIES.

Journal Article NASA Technical Memorandum · January 1, 1984 An analytical model for investigating vibration and flutter of mistuned bladed disk assemblies is presented. This model accounts for elastic, inertial and aerodynamic coupling between bending and torsional motions of each individual blade, elastic and iner ... Cite

Flutter of turbofan rotors with mistuned blades

Journal Article AIAA Journal · January 1, 1984 A set of aeroelastic equations describing the motion of an arbitrarily mistuned rotor with flexible, pretwisted, nonuniform blades is developed using an extended Hamilton's principle. The derivation of the equations has its basis in the geometric nonlinear ... Full text Cite

Flutter of swept fan blades.

Journal Article · January 1, 1984 The purpose of the research presented in this paper is to study the effect of sweep on fan blade flutter by applying the analytical methods developed for aeroelastic analysis of advanced turboprops. Two methods are used. The first method utilizes an approx ... Cite

VIBRATION AND FLUTTER OF MISTUNED BLADED-DISK ASSEMBLIES.

Journal Article NASA Technical Memorandum · January 1, 1984 An analytical model for investigating vibration and flutter of mistuned bladed disk assemblies is presented. This model accounts for elastic, inertial and aerodynamic coupling between bending and torsional motions of each individual blade, elastic and iner ... Cite

LEWIS RESEARCH CENTER SPIN RIG AND ITS USE IN VIBRATION ANALYSIS OF ROTATING SYSTEMS.

Journal Article NASA Technical Paper · January 1, 1984 The Lewis Research Center spin rig was constructed to provide experimental evaluation of analysis methods developed under the NASA Engine Structural Dynamics Program. Rotors up to 51 cm (20in. ) in diameter can be spun to 16,000 rpm up to 51 cm (20 in. ) i ... Cite

FLUTTER OF SWEPT FAN BLADES.

Journal Article NASA Technical Memorandum · January 1, 1984 The purpose of the research presented in this paper is to study the effect of sweep on fan blade flutter by applying the analytical methods developed for aeroelastic analysis of advance turboprops. Two methods are used. The first method utilizes an approxi ... Cite

Natural frequencies of twisted rotating plates

Journal Article Journal Of Sound And Vibration · 1984 Cite

EFFECTS OF STRUCTURAL COUPLING ON MISTUNED CASCADE FLUTTER AND RESPONSE.

Conference American Society of Mechanical Engineers (Paper) · December 1, 1983 Cite

EFFECTS OF STRUCTURAL COUPLING ON MISTUNED CASCADE FLUTTER AND RESPONSE.

Journal Article NASA Technical Memorandum · March 27, 1983 The effects of structural coupling on mistuned cascade flutter and response are analytically investigated using an extended typical section model. Previous work using two degree of freedom per blade typical section models has included only aerodynamic coup ... Cite

Aeroelastic characteristics of a cascade ofmistimed blades in subsonic and supersonic flows

Journal Article Journal of Vibration and Acoustics, Transactions of the ASME · January 1, 1983 An investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic andstructural coupling between the bending and torsional motions and the aerodynamic coupling between th ... Full text Cite

EFFECTS OF STRUCTURAL COUPLING ON MISTUNED CASCADE FLUTTER AND RESPONSE.

Journal Article NASA Technical Memorandum · January 1, 1983 The effects of structural coupling on mistuned cascade flutter and response are analytically investigated using an extended typical section model. Previous work using two degree of freedom per blade typical section models has included only aerodynamic coup ... Cite

BENDING-TORSION FLUTTER OF A HIGHLY SWEPT ADVANCED TURBOPROP.

Journal Article NASA Technical Memorandum · December 1, 1982 Experimental and analytical results are presented for a bending-torsion flutter phenomena encountered during wind-tunnel testing of a ten-bladed, advanced, high-speed propeller (turboprop) model with thin airfoil sections, high blade sweep, low aspect rati ... Cite

COUPLED BENDING-BENDING-TORSION FLUTTER OF A MISTUNED CASCADE WITH NONUNIFORM BLADES.

Journal Article NASA Tech Memo · May 10, 1982 A SET OF AEROELASTIC EQUATIONS DESCRIBING THE MOTION OF AN ARBITRARILY MISTUNED CASCADE WITH FLEXIBLE, PRETWISTED, NONUNIFORM BLADES IS DEVELOPED USING AN EXTENDED HAMILTON'S PRINCIPLE. A GENERAL EXPRESSION FOR FORESHORTENING OF A BLADE ISDERIVED AND IS EX ... Cite

Flutter and response of a mistuned cascade in incompressible flow

Conference AIAA Journal · January 1, 1982 This paper presents an investigation of the effects of blade mistiming on the aeroelastic stability and response of a cascade in incompressible flow. The aerodynamic, inertial, and structural coupling between the bending and torsional motions of each blade ... Full text Cite

COUPLED BENDING-BENDING-TORSION FLUTTER OF A MISTUNED CASCADE WITH NONUNIFORM BLADES.

Journal Article NASA Tech Memo · January 1, 1982 A SET OF AEROELASTIC EQUATIONS DESCRIBING THE MOTION OF AN ARBITRARILY MISTUNED CASCADE WITH FLEXIBLE, PRETWISTED, NONUNIFORM BLADES IS DEVELOPED USING AN EXTENDED HAMILTON'S PRINCIPLE. A GENERAL EXPRESSION FOR FORESHORTENING OF A BLADE ISDERIVED AND IS EX ... Cite

BENDING-TORSION FLUTTER OF A HIGHLY SWEPT ADVANCED TURBOPROP.

Journal Article NASA Technical Memorandum · January 1, 1982 Experimental and analytical results are presented for a bending-torsion flutter phenomena encountered during wind-tunnel testing of a ten-bladed, advanced, high-speed propeller (turboprop) model with thin airfoil sections, high blade sweep, low aspect rati ... Cite

AEROELASTIC CHARACTERISTICS OF A CASCADE OF MISTUNED BLADES IN SUBSONIC AND SUPERSONIC FLOWS.

Journal Article American Society of Mechanical Engineers (Paper) · December 1, 1981 An investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic coupling between t ... Cite

AEROELASTIC CHARACTERISTICS OF A CASCADE OF MISTUNED BLADES IN SUBSONIC AND SUPERSONIC FLOWS.

Journal Article NASA Technical Memorandum · December 1, 1981 An investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic coupling between t ... Cite

Aeroelastic characteristics of a cascade of mistuned blades in subsonic and supersonic flows.

Journal Article · January 1, 1981 The results of an investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic cou ... Cite

EFFECTS OF MISTUNING ON BENDING-TORSION FLUTTER AND RESPONSE OF A CASCADE IN INCOMPRESSIBLE FLOW.

Conference Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference · January 1, 1981 This paper presents an investigation of the effects of blade mistuning on the aeroelastic stability and response of a cascade in incompressible flow. The aerodynamic, inertial, and structural coupling between the bending and torsional motions of each blade ... Cite

AEROELASTIC CHARACTERISTICS OF A CASCADE OF MISTUNED BLADES IN SUBSONIC AND SUPERSONIC FLOWS.

Journal Article NASA Technical Memorandum · January 1, 1981 An investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic coupling between t ... Cite

AEROELASTIC CHARACTERISTICS OF A CASCADE OF MISTUNED BLADES IN SUBSONIC AND SUPERSONIC FLOWS.

Journal Article American Society of Mechanical Engineers (Paper) · January 1, 1981 An investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic coupling between t ... Cite

Aeroelastic characteristics of a cascade of mistuned blades in subsonic and supersonic flows.

Journal Article · January 1, 1981 The results of an investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic cou ... Cite

AEROELASTIC CHARACTERISTICS OF A CASCADE OF MISTUNED BLADES IN SUBSONIC AND SUPERSONIC FLOWS.

Conference American Society of Mechanical Engineers (Paper) · January 1, 1981 An investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic coupling between t ... Cite

Vibration and buckling of rectangular plates under in-plane hydrostatic loading

Journal Article Journal of Sound and Vibration · June 22, 1980 Numerical solutions are presented for the fundamental natural frequency and mode shape of a rectangular plate loaded by in-plane hydrostatic forces for a wide variety of aspect ratios, boundary conditions, and load magnitudes. All six possible combinations ... Full text Cite

Structural analysis of a cooled, directionally solidified turbine blade

Journal Article Journal of Aircraft · January 1, 1977 Directionally solidifed, air-cooled turbine blades present new challenges to the structural design analyst. This paper describes an investigation of turbine blade failures encountered during a recent engine development program. The effect of wall tolerance ... Full text Cite

Modeling engine static structures with conical shell finite elements

Journal Article Journal of Aircraft · January 1, 1975 The conical shell element with nonsymmetric loading and displacement capabilities has excellent possibilities for application to engine static structures. The major benefit would be a dramatic reduction in computer time as compared with a plate model, howe ... Full text Cite