ConferenceAIAA Science and Technology Forum and Exposition AIAA Scitech Forum 2026 · January 1, 2026
Aeroelastic flutter onset and limit cycle oscillation results are computed for a two-dimensional model of the NASA benchmark supercritical wing configuration consisting of the NASA SC(2)0414 airfoil section. The purpose of this investigation is to contribu ...
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ConferenceAIAA Science and Technology Forum and Exposition AIAA Scitech Forum 2025 · January 1, 2025
Aeroelastic limit cycle oscillation results are presented for a three-degree-of-freedom plunge, pitch, and flap structural model with flap free-play in a viscous transonic flow airfoil. A nonlinear frequency domain harmonic balance approach is used for the ...
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ConferenceAIAA Science and Technology Forum and Exposition AIAA Scitech Forum 2025 · January 1, 2025
This paper investigates the flutter mechanism of the benchmark supercritical wing at Mach 0.8 with the angle-of-attack (AOA) at 1◦, 3◦ and 5◦. Nonlinear unsteady aerodynamic reduced order models (ROMs) are used which are tr ...
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ConferenceAIAA Scitech Forum and Exposition 2023 · January 1, 2023
Presented is a technique that significantly improves the computational performance of an existing harmonic balance-based flutter onset and limit-cycle oscillation aeroelastic solution methodology. The existing harmonic balance aeroelastic solution methodol ...
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ConferenceAIAA Science and Technology Forum and Exposition AIAA Scitech Forum 2022 · January 1, 2022
A methodology for leveraging a combination of linear (through convolution integrals) and nonlinear (through Volterra series) reduced-order modeling (ROM) development was demonstrated on both a 2 and 3 degree of freedom (DOF) aeroelastic system. The linear/ ...
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ConferenceAIAA Aviation 2022 Forum · January 1, 2022
Presented is a point collocation non-intrusive polynomial chaos approach for nonlinear aeroelastic uncertainty quantification analysis. A unique aspect of our approach is that we are using a nonlinear frequency-domain harmonic balance aeroelastic solution ...
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ConferenceAIAA Scitech 2021 Forum · January 1, 2021
Presented is an automatic differentiation based nonlinear reduced-order modeling technique which includes geometric variation computation capability. The method is based on a Taylor series expansion of a nonlinear frequency-domain harmonic balance based co ...
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ConferenceAIAA Aviation and Aeronautics Forum and Exposition AIAA Aviation Forum 2021 · January 1, 2021
We have recently developed an automatic differentiation based nonlinear reduced-order modeling technique. The method is based on a Taylor series expansion of a nonlinear frequencydomain harmonic balance based computational fluid dynamic solver residual. In ...
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ConferenceAIAA Scitech 2020 Forum · January 1, 2020
Presented is a methodology for numerically stabilizing harmonic balance based aeroelastic solution approaches. The governing harmonic balance based aeroelastic equations are a stationary/steady system of equations. In order to solve these equations, many r ...
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ConferenceAIAA Aviation 2020 Forum · January 1, 2020
We present the details of two primary research topics in the area of aeroelastic optimization that we are currently working on. The first topic is a new discrete adjoint aeroelastic design optimization solution methodology, which has a computational cost t ...
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ConferenceJournal of Aerospace Information Systems · January 1, 2019
Modern computational fluid dynamic simulations of flows about naval vessels produce an enormous amount of flow-field data. The computations are performed in order to model details of the erratic unsteady flows that can occur about naval superstructures. Th ...
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ConferenceInternational Forum on Aeroelasticity and Structural Dynamics 2019 Ifasd 2019 · January 1, 2019
During the design and analysis of aircraft flutter boundaries are typically computed using the p-k iterations, k iterations, p iterations, or eigenvalue analysis, that require computationally expensive and numerically sensitive procedures especially for co ...
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ConferenceAIAA ASCE AHS ASC Structures Structural Dynamics and Materials Conference 2018 · January 1, 2018
Presented is a fixed point iteration approach for harmonic balance computational flow solver based nonlinear aeroelastic computations. The methodology allows for the aeroelastic governing equations to be solved simultaneously, in an iterative manner, along ...
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Conference2018 Modeling and Simulation Technologies Conference · January 1, 2018
In the following paper, we demonstrate the use of both proper orthogonal decomposition and Fourier series decomposition approaches for airwake dataset compression. The proper orthogonal decomposition method is used for compressing airwake data in the time- ...
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Conference33rd Wind Energy Symposium · January 1, 2015
Steps taken to develop aeroelastic modeling of wind turbine blades derived from the unsteady Navier-Stokes equations and a mode shape-based structural dynamics model are presented. For turbulent flows, the system is closed with the Spalart-Allmaras turbule ...
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Conference16th AIAA Issmo Multidisciplinary Analysis and Optimization Conference · January 1, 2015
Presented is a discrete adjoint method for transonic buffet design optimization. The method is based on a frequency do-main approach for modeling unsteady aerodynamics. Automatic differentiation is used to derive the computer code representing the adjoint ...
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ConferenceAIAA Aviation 2014 15th AIAA Issmo Multidisciplinary Analysis and Optimization Conference · January 1, 2014
Using aeroelastic flutter geometric design sensitivities provided by a recently developed discrete adjoint aeroelastic solver, the shape of a NLR 7301 airfoil section is optimized to increase flutter onset velocity for a benchmark transonic aeroelastic con ...
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ConferenceProceedings 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 ...
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ConferenceProceedings 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 ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · August 15, 2013
Presented is a discrete adjoint approach for computing nonlinear aeroelastic design sensitivities for transonic and viscous flows based on Reynolds Averaged Navier-Stokes computational fluid dynamic models. The method is based on a harmonic balance nonline ...
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Conference54th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · August 2, 2013
Presented is a discrete adjoint approach for computing nonlinear aeroelastic design sensitivities for transonic and viscous flows based on Reynolds Averaged Navier-Stokes computational fluid dynamic models. The method is based on a harmonic balance nonline ...
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ConferenceAIAA Journal · May 1, 2013
A new numerical technique for the stabilization of explicit computational-fluid-dynamic solvers is presented. When using computational-fluid-dynamic codes to solve practical problems one sometimes finds the solution fails to converge due to the presence of ...
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Conference50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition · December 1, 2012
This paper discusses the development and implementation of an automatic differentiation based nonlinear reduced order model for unsteady separated flows. The objective of the research presented herein has been to test the capability and limits of the metho ...
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Conference50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition · December 1, 2012
A new numerical technique for the stabilization of explicit computational fluid dynamic (CFD) solvers is presented. When using CFD codes to solve practical problems, one sometimes finds the solution fails to converge due to the presence of a small number o ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · December 16, 2010
Presented are flutter-onset trends of the F-16 fighter computed using a harmonic balance version of the NASA OVERFLOW 2 flow solver code. The harmonic technique enables one to model unsteady aerodynamics and aeroelastic response in the frequency domain wit ...
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ConferenceProceedings of the ASME Turbo Expo · December 1, 2010
The computation time and the extraction of useful information remain severe drawbacks to systematic use of modern three-dimensional Navier-Stokes codes in a design procedure of multistage turbomachines. That explains why throughflow simulation is still wid ...
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ConferenceProceedings of the ASME Turbo Expo · December 1, 2010
Capturing a level of modeling of the flow inside a multi-stage turbomachine, such as unsteadiness for example, can be done at different degrees of details, either by capturing all deterministic features of the flow with a pure unsteady method or by settlin ...
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Conference19th AIAA Computational Fluid Dynamics Conference · January 1, 2009
A novel approach for implementing a nonlinear unsteady frequency domain harmonic balance solution technique about existing implicit computational fluid dynamic flow solvers is presented. This approach uses an explicit discretization of the harmonic balance ...
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Conference47th 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 ...
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ConferenceProceedings of the ASME Turbo Expo · December 1, 2008
In 1997 the Turbomachinery group of the University of Liège decided to acquire a small jet engine to illustrate the courses in propulsion and to provide the students with the opportunity to get some experience in data measurement, acquisition and interpret ...
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ConferenceProceedings of the ASME Turbo Expo · December 1, 2008
The computation time and the extraction of useful information remain severe drawbacks to systematic use of modern three-dimensional Navier-Stokes codes in a design procedure of multistage turbomachines. That explains why throughflow simulation is still wid ...
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ConferenceProceedings 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 ...
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ConferenceIcas 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 ...
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ConferenceCollection of Technical Papers U S Air Force T and E Days 2007 Test and Evaluation · November 5, 2007
In the following, we present computational aeroelastic flutter onset and limit cycle oscillation response trends for various stores and weapons configurations of the F-16 fighter. A nonlinear harmonic balance compressible Reynolds averaged Navier-Stokes co ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · December 1, 2006
A computational investigation of flutter onset and limit cycle oscillations of the F-16 fighter using a nonlinear frequency-domain harmonic-balance approach is presented. In this latest study, we examine the sensitivity of computed aeroelastic behavior to ...
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ConferenceCollection 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 ...
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ConferenceCollection of Technical Papers 11th AIAA Issmo Multidisciplinary Analysis and Optimization Conference · January 1, 2006
Presented is a technique for developing a nonlinear reduced order model of a computational fluid dynamic solver. The method is based on a Taylor series expansion of a frequency domain harmonic balance computational fluid dynamic solver residual. The comput ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · December 19, 2005
A computational investigation of limit cycle oscillation behavior of the F-16 fighter configuration using a nonlinear frequency-domain harmonic-balance approach is presented. The research discussed in this latest paper is a follow-on to our work presented ...
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Conference12th 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 ...
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Conference43rd 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 ...
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Conference43rd 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 ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · December 1, 2004
A computational investigation of limit cycle oscillation behavior of the F-16 fighter configuration using a nonlinear frequency-domain harmonic-balance approach is presented. Computed limit cycle response results correlate well with experiment. Details of ...
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Conference33rd AIAA Fluid Dynamics Conference and Exhibit · December 1, 2003
In this paper, we review frequency domain techniques for computing unsteady flows in turbomachinery. The frequency domain approaches, which can be used to model both small-disturbance and nonlinear time periodic flows, are computationally very efficient, t ...
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Conference41st Aerospace Sciences Meeting and Exhibit · December 1, 2003
Presented is a discrete adjoint approach for computing steady and unsteady aerodynamic design sensitivities for compressible viscous flows about airfoil configurations. The nominal flow solver method is based on a harmonic balance solution technique, which ...
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Conference44th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · December 1, 2003
Presented is an investigation into the modeling of limit cycle oscillation (LCO) behavior of an experimental transonic airfoil aeroelastic configuration using a frequency-domain harmonic-balance (HB) computational fluid dynamic (CFD) approach. The aeroelas ...
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Conference41st Aerospace Sciences Meeting and Exhibit · January 1, 2003
Presented is a discrete adjoint approach for computing steady and unsteady aerodynamic design sensitivities for compressible viscous flows about airfoil configurations. The nominal flow solver method is based on a harmonic balance solution technique, which ...
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ConferenceAmerican 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 ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2003
Presented is an investigation into the modeling of limit cycle oscillation (LCO) behavior of an experimental transonic airfoil aeroelastic configuration using a frequency-domain harmonic-balance (HB) computational fluid dynamic (CFD) approach. The aeroelas ...
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ConferenceASME International Mechanical Engineering Congress and Exposition Proceedings · January 1, 2002
Presented is a frequency domain harmonic balance (HB) technique for modeling nonlinear unsteady aerodynamics of three-dimensional transonic inviscid flows about wing configurations. The method can be used to model efficiently nonlinear unsteady aerodynamic ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2002
Presented is a harmonic-balance (HB) computational fluid dynamic (CFD) approach for modeling limit cycle oscillation (LCO) behavior of aeroelastic airfoil configurations in a viscous transonic flow. For the NLM 7301 airfoil configuration studied, accountin ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2002
A parameter study of transonic airfoil flutter and limit cycle oscillation (LCO) behavior was presented. The effect of structural parameters and freestream Mach number of a transonic flow on the flutter and LCO was found out using inviscid computational fl ...
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Conference19th AIAA Applied Aerodynamics Conference · December 1, 2001
Limit cycle oscillations have been observed in flight operations of modern aircraft, wind tunnel experiments and mathematical models. Both fluid and structural nonlinearities are thought to contribute to these phenomena. With recent advances in reduced ord ...
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Conference19th AIAA Applied Aerodynamics Conference · December 1, 2001
The proper orthogonal decomposition (POD) based reduced order modeling (ROM) technique for modeling unsteady frequency domain aerodynamics is developed for a large scale computational model of an inviscid flow transonic wing configuration. Using the method ...
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Conference19th AIAA Applied Aerodynamics Conference · December 1, 2001
Using a state of the art computational fluid dynamic (CFD) method to model nonlinear steady and unsteady transonic flows in conjunction with a linear structural model, an investigation is made into how nonlinear aerodynamics can effect the divergence, flut ...
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Conference39th Aerospace Sciences Meeting and Exhibit · December 1, 2001
Presented is a newly devised static/dynamic correction approach for eigenvector expansion based reduced-order modeling (ROM). When compared to the fundamental Ritz ROM formulation, along with the static and multiple static correction ROM approaches, the te ...
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Conference19th AIAA Applied Aerodynamics Conference · January 1, 2001
The proper orthogonal decomposition (POD) based reduced order modeling (ROM) technique for modeling unsteady frequency domain aerodynamics is developed for a large scale computational model of an inviscid flow transonic wing configuration. Using the method ...
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Conference19th AIAA Applied Aerodynamics Conference · January 1, 2001
Limit cycle oscillations have been observed in flight operations of modern aircraft, wind tunnel experiments and mathematical models. Both fluid and structural nonlinearities are thought to contribute to these phenomena. With recent advances in reduced ord ...
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Conference19th AIAA Applied Aerodynamics Conference · January 1, 2001
Using a state of the art computational fluid dynamic (CFD) method to model nonlinear steady and unsteady transonic flows in conjunction with a linear structural model, an investigation is made into how nonlinear aerodynamics can effect the divergence, flut ...
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Conference39th Aerospace Sciences Meeting and Exhibit · January 1, 2001
Presented is a newly devised static/dynamic correction approach for eigenvector expansion based reduced-order modeling (ROM). When compared to the fundamental Ritz ROM formulation, along with the static and multiple static correction ROM approaches, the te ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2001
The proper orthogonal decomposition (POD) based reduced order modeling (ROM) technique for modeling unsteady frequency domain aerodynamics is developed for a large scale computational model of an inviscid flow transonic wing configuration. Using the method ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2001
Limit cycle oscillations have been observed in flight operations of modern aircraft, wind tunnel experiments and mathematical models. Both fluid and structural nonlinearities are thought to contribute to these phenomena. With recent advances in reduced ord ...
Cite
ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2001
Using a state of the art computational fluid dynamic (CFD) method to model nonlinear steady and unsteady transonic flows in conjunction with a linear structural model, an investigation is made into how nonlinear aerodynamics can effect the divergence, flut ...
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Conference37th Aerospace Sciences Meeting and Exhibit · January 1, 1999
A new method for constructing reduced-order models (ROM) of unsteady small-disturbance flows is presented. The reduced-order models are constructed using basis vectors determined from the proper orthogonal decomposition (POD) of an ensemble of small-distur ...
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ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 1999
A review is given on the status of reduced order modeling of unsteady aerodynamic systems. Starting with either a time domain or frequency domain computational fluid dynamics (CFD) analysis of unsteady aerodynamic flows, a large, sparse eigenvalue is solve ...
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Conference13th Computational Fluid Dynamics Conference · January 1, 1997
Higher order upwind leapfrog schemes for two dimensional advection, acoustics and aeroacoustics are developed and applied to several examples. Advection schemes are applied to scalar advection with uniform and nonuniform creeping flow speed. Acoustics sche ...
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Conference12th Computational Fluid Dynamics Conference · January 1, 1995
To develop numerical schemes for aeroacoustics, numerical techniques based upon the upwind leapfrog method have been devised and tested on some model problems. Fourth-order variations of the upwind leapfrog scheme are studied and methods for applying these ...
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Conference11th Computational Fluid Dynamics Conference 1993 · January 1, 1993
The ability of popular computational fluid dynamic (CFD) methods to simulate the propagation of acoustic waves is assessed both theoretically and by numerical experiment. The schemes are used to model acoustic waves generated by a noise source situated at ...
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