Scholars@Duke
Donald B. Bliss

Donald B. Bliss

Associate Professor of the Thomas Lord Department of Mechanical Engineering and Materials Science
Thomas Lord Department of Mechanical Engineering and Materials Science
donald.bliss@duke.edu
148B Engineering Bldg, Box 90300, Durham, NC 27708-0300
148B Engineering Bldg, Box 90300, Durham, NC 27708

Selected Publications

A numerical study of tilt-based wake steering using a hybrid free-wake method

Journal Article Wind Energy · February 1, 2020 This study investigates the potential of using tilt-based wake steering to alleviate wake shielding problems experienced by downwind turbines. Numerical simulations of turbine wakes have been conducted using a hybrid free-wake analysis combining vortex lat ... Full text Cite

Benchmark analytical solutions for steady state high frequency broadband sound fields in three rectangular enclosures.

Journal Article The Journal of the Acoustical Society of America · April 2019 Analytical solutions are presented for broadband sound fields in three rectangular enclosures with absorption applied on the floor and ceiling, rigid sidewalls, and a vertically oriented dipole source. The solutions are intended to serve as benchmarks that ... Full text Cite

A novel hybrid free-wake model for wind turbine performance and wake evolution

Journal Article Renewable Energy · February 1, 2019 A new free-wake analysis for wind turbine aerodynamics is developed to accurately predict turbine performance and downstream wake evolution. A key feature is the Constant Circulation Contour Method (CCCM) which is a novel free-wake model for wind turbine w ... Full text Cite

A hybrid free wake simulation comparison of turbine wake steering with innovative turbine designs

Conference Proceedings of the ASME Turbo Expo · January 1, 2017 Wake shielding in wind farms caused by the interaction of upstream energy-depleted wakes and down-stream turbines substantially reduces individual turbine efficiency and overall wind farm performance. A method is studied to alleviate this problem using sha ... Full text Cite

Wind farm performance improvement by using wake transport

Conference Annual Forum Proceedings - AHS International · January 1, 2016 Wake shielding on wind farms substantially reduces the efficiency of downstream wind turbines due to the interaction with the energy-depleted wakes from upwind turbines. This research considers a method to mitigate the wake shielding effect by tilting the ... Cite

New look at unsteady supersonic potential flow aerodynamics and piston theory

Journal Article AIAA Journal · September 1, 2013 Piston theory is an inherently quasi-steady theory, in that higher powers of frequency do not appear, as well as a local theory in that the pressure at a point on the airfoil only depends on the downwash at the same point. In the extension to piston theory ... Full text Cite

Sound attenuation and prediction of porous media properties in hybrid ducts utilizing spatially periodic area changes

Journal Article 2008 Proceedings of the NoiseCon/ASME NCAD, NCAD 2008 · October 16, 2009 A theory based on cross-sectional averaging is developed to analyze quasi-one-dimensional acoustic propagation in hybrid ducts with two propagation media in the cross-section. Specifically, ducts lined with a thick layer of porous material are considered. ... Cite

Noise reduction strategies using multi-element flexible structures

Journal Article 2008 Proceedings of the NoiseCon/ASME NCAD, NCAD 2008 · October 16, 2009 Sound transmission through multi-element flexible barriers is studied. Configurations analyzed include panels with different thickness and elastic modulus in different regions and layered structures connected by an elastic suspension. The purpose of the re ... Cite

Characterization of high frequency radiation from panels subject to broadband excitation

Journal Article 2008 Proceedings of the NoiseCon/ASME NCAD, NCAD 2008 · October 16, 2009 In the high frequency limit, a vibrating panel subject to spatially-random temporally-broadband forcing is shown to have broadband power and directivity properties that can be expressed in simple analytical terms by a limited set of parameters. A lightly-l ... Cite

Prediction and modification of broadband interior noise in enclosures using energy-intensity bem and absorption scaling

Journal Article 2008 Proceedings of the NoiseCon/ASME NCAD, NCAD 2008 · October 16, 2009 Enclosures with difliise reflection boundaries are modeled with an energy-intensity boundary element method using uncorrelated broadband directional sources. Input power is assumed to enter the enclosure through the walls, which are also absorptive. An abs ... Cite

Characterization of high frequency radiation from panels subject to broadband excitation

Journal Article American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD · December 1, 2008 In the high frequency limit, a vibrating panel subject to spatially-random temporally-broadband forcing is shown to have broadband power and directivity properties that can be expressed in simple analytical terms by a limited set of parameters. A lightly-l ... Full text Cite

Noise reduction strategies using multi-element flexible structures

Journal Article American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD · December 1, 2008 Sound transmission through multi-element flexible barriers is studied. Configurations analyzed include panels with different thickness and elastic modulus in different regions and layered structures connected by an elastic suspension. The purpose of the re ... Full text Cite

Prediction and modification of broadband interior noise in enclosures using energy-intensity bem and absorption scaling

Journal Article American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD · December 1, 2008 Enclosures with diffuse reflection boundaries are modeled with an energy-intensity boundary element method using uncorrelated broadband directional sources. Input power is assumed to enter the enclosure through the walls, which are also absorptive. An abso ... Full text Cite

Sound attenuation and prediction of porous media properties in hybrid ducts utilizing spatially periodic area changes

Journal Article American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCAD · December 1, 2008 A theory based on cross-sectional averaging is developed to analyze quasi-one-dimensional acoustic propagation in hybrid ducts with two propagation media in the cross-section. Specifically, ducts lined with a thick layer of porous material are considered. ... Full text Cite

Theoretical and experimental study of sound propagation in ducts with spatially periodic area changes

Journal Article 12th International Congress on Sound and Vibration 2005, ICSV 2005 · December 1, 2005 Sound propagation of one-dimensional waves through a tube with periodic area changes is studied theoretically and experimentally. The resulting wave behavior is similar to that observed for periodic structures, with Bloch waves, pass-bands and stop-bands. ... Cite

Vibro-acoustic behavior of finite-length fluid-loaded periodic structures using local-global homogenization

Journal Article 12th International Congress on Sound and Vibration 2005, ICSV 2005 · December 1, 2005 Local-Global Homogenization (LGH) is a method to predict directly the smooth global response of periodic fluid-loaded structures in a self-contained manner. Many fluid-loaded structures, such as fuselages and hulls, have periodically spaced braces, ribs, o ... Cite

Prediction of broadband sound fields in enclosures by decomposition in powers of an absorption parameter

Journal Article 12th International Congress on Sound and Vibration 2005, ICSV 2005 · December 1, 2005 A novel analysis for steady-state or time-dependent broadband diffuse sound fields in enclosures is developed. Beginning with a formulation utilizing broadband intensity boundary sources, the strength of these wall sources is expanded in a series in powers ... Cite

Analytical-numerical matching for fluid-loaded structures with discontinuities

Journal Article Journal of the Acoustical Society of America · November 1, 2004 The method of analytical-numerical matching (ANM) is applied to several example problems involving the radiation and vibration of a fluid-loaded cylindrical shell with structural discontinuities. These problems are used to verify the accuracy of the method ... Full text Cite

Local/global homogenization of fluid-loaded periodic structures

Journal Article Journal of the Acoustical Society of America · August 1, 2004 A novel homogenization method for periodic structures that utilizes a local/global separation of the high and low wavenumber spectrum is presented. The low-wavenumber global problem has an infinite-order operator. The global problem is self-contained; loca ... Full text Cite

Calculation of the radiated sound field from a fluid-loaded plate with periodic structural discontinuities

Journal Article Proceedings of the Tenth International Congress on Sound and Vibration · December 1, 2003 Many periodic structures are subjected to forcing by a propagating pressure field. Examples include incident sound fields reflected off submerged ribbed hulls, and interior noise radiated from aircraft fuselages forced by an external turbulent boundary lay ... Cite

Efficient calculation of vibration and radiation from fluid-loaded structures with discontinuities using analytical-numerical matching

Journal Article Proceedings of the Tenth International Congress on Sound and Vibration · December 1, 2003 Solving structural acoustic problems in the mid-frequency range is a challenging task. Computation is expensive due to the large well-coupled nature of the fluid-structure system. Discrete structural elements cause localized discontinuities that require mu ... Cite

The development of novel vibration resistant structures through the use of coupled multi-element configurations

Journal Article Proceedings of the Tenth International Congress on Sound and Vibration · December 1, 2003 Very often structures are designed to perform a primary function and vibration is an unwanted consequence. It is desirable to develop structural configurations that naturally resist vibration while still satisfying their basic function. This paper describe ... Cite

Aeroelastic wing with leading- and trailing-edge control surfaces

Journal Article Journal of Aircraft · January 1, 2003 It is well known that the effectiveness of a trailing-edge control surface can be substantially diminished due to the elastic twist of an airfoil or wing. This aeroelastic phenomenon is known as control surface reversal when the lift or roll rate vanishes ... Full text Cite

An acoustic boundary element method based on energy and intensity variables for prediction of high-frequency broadband sound fields

Journal Article Journal of the Acoustical Society of America · December 29, 2001 A boundary element method is formulated in terms of time-averaged energy and intensity variables. The approach is applicable to high modal density fields but is not restricted to the usual low-absorption, diffuse, and quasiuniform assumptions. A broadband ... Full text Cite

An estimate of airframe noise caused by structural vibration

Journal Article 6th Aeroacoustics Conference and Exhibit · December 1, 2000 Airframe noise due to structural vibration is estimated. This estimate shows that panel vibration driven by turbulent boundary layer fluctuations can produce airframe noise levels comparable to those measured on aerodynamically "clean" airframe configurati ... Cite

Energy based boundary element method for broadband high frequency sound fields

Journal Article 6th Aeroacoustics Conference and Exhibit · December 1, 2000 An acoustic boundary element method is formulated using the time-averaged intensity and mean-square pressure. A continuous distribution of uncorrelated broadband high frequency sources is used to represent the boundaries of the enclosure. Local correlation ... Cite

An estimate of airframe noise caused by structural vibration

Conference 6th Aeroacoustics Conference and Exhibit · January 1, 2000 Airframe noise due to structural vibration is estimated. This estimate shows that panel vibration driven by turbulent boundary layer fluctuations can produce airframe noise levels comparable to those measured on aerodynamically "clean" airframe configurati ... Full text Cite

Energy based boundary element method for broadband high frequency sound fields

Conference 6th Aeroacoustics Conference and Exhibit · January 1, 2000 An acoustic boundary element method is formulated using the time-averaged intensity and mean-square pressure. A continuous distribution of uncorrelated broadband high frequency sources is used to represent the boundaries of the enclosure. Local correlation ... Full text Cite

Scattering from fluid-loaded cylindrical shell with periodic circumferential constraints using analytical/numerical matching

Journal Article Journal of the Acoustical Society of America · September 1, 1999 Acoustic scattering from an infinitely long, thin elastic cylindrical shell with axially periodic circumferential constraints leads to the excitation of flexural, longitudinal, and shear waves on the shell. Of interest is the interaction of these structura ... Full text Cite

Unsteady compressible boundary element calculations of parallel blade-vortex interaction

Journal Article Journal of the American Helicopter Society · January 1, 1999 A method for calculating parallel blade vortex interaction (BVI) has been developed. The technique is based on the application of a three-dimensional aeroacoustic boundary element formulation using Analytical/Numerical Matching in conjunction with a recent ... Full text Cite

Analytical/numerical matching for efficient calculation of scattering from cylindrical shells with lengthwise constraints

Journal Article Journal of the Acoustical Society of America · April 1, 1998 Structural discontinuities in highly coupled fluid-structure systems are modeled by an approach called analytical/numerical matching (ANM). This method separates the low-resolution global influence of a discontinuity from the relatively high-resolution loc ... Full text Cite

A discussion of modal uncoupling and an approximate closed-form solution for weakly coupled systems with application to acoustics

Journal Article Journal of the Acoustical Society of America · April 1, 1998 Modal analysis is often used to solve problems in acoustics, leading to a system of coupled equations for the modal amplitudes. A common practice in analytical work utilizing modal analysis has been to assume that weak modal coupling is negligible, thereby ... Full text Cite

Unsteady compressible boundary element calculations of parallel blade-vortex interaction

Conference 36th AIAA Aerospace Sciences Meeting and Exhibit · January 1, 1998 © 1998 by The Boeing Company. Published by the American Institute of Aeronautics and Astronautics, Inc.A novel method for calculating parallel blade vortex interaction (BVI) has been developed. The technique is based on the application of a three-dimension ... Cite

Unsteady compressible boundary element calculations of parallel blade-vortex interaction

Conference 36th AIAA Aerospace Sciences Meeting and Exhibit · January 1, 1998 © 1998 by The Boeing Company. Published by the American Institute of Aeronautics and Astronautics, Inc. A novel method for calculating parallel blade vortex interaction (BVI) has been developed. The technique is based on the application of a three-dimensio ... Cite

Unsteady compressible boundary element calculations of parallel blade-vortex interaction

Conference 36th AIAA Aerospace Sciences Meeting and Exhibit · January 1, 1998 A novel method for calculating parallel blade vortex interaction (BVI) has been developed. The technique is based on the application of a three-dimensional aeroacoustic boundary element formulation using Analytical/Numerical Matching in conjunction with a ... Full text Cite

Prediction of viscous trailing vortex structure from basic loading parameters

Journal Article AIAA Journal · January 1, 1998 An analytical method has been developed to predict the structure of a fully developed trailing vortex with a viscous core. Vortex structure is calculated from the load distribution on the generating wing and fundamental conservation laws are satisfied. The ... Full text Cite

The application of analytical/numerical matching to structural discontinuities in structural/acoustic problems

Journal Article Journal of the Acoustical Society of America · February 1, 1997 Analytical/numerical matching (ANM) is introduced to more efficiently model structural discontinuities in structural/acoustic problems. The general method is explained in detail for the simple example problem of normal incidence acoustic scattering from a ... Full text Cite

An analytical/numerical matching – Turbulent core model blade vortex intertaction study

Conference 3rd AIAA/CEAS Aeroacoustics Conference · January 1, 1997 A novel method for calculating parallel two-dimensional blade vortex interaction (BVI) has been developed. The technique is based on the application of an aeroacoustic boundary element formulation using Analytical/Numerical Matching (ANM) in conjunction wi ... Full text Cite

An acoustic boundary element method using analytical/numerical matching

Journal Article Journal of the Acoustical Society of America · January 1, 1997 Analytical/numerical matching (ANM) is a hybrid scheme combining a low- resolution global numerical solution with a high-resolution local solution to form a composite solution. ANM is applied to a harmonically oscillating body to calculate the radiated aco ... Full text Cite

Aeroacoustic boundary element method using analytical/numerical matching

Journal Article AIAA Journal · January 1, 1997 A unified aeroacoustic boundary element theory has been formulated using analytical/numerical matching (ANM). ANM is a hybrid scheme combining a low-resolution global numerical solution with high-resolution local solutions to form a composite solution. ANM ... Full text Cite

Prediction of turbulent trailing vortex structure from basic loading parameters

Conference 14th Applied Aerodynamics Conference · January 1, 1996 A novel analytical method has been developed to accurately predict the core structure of a fully developed trailing vortex. Properties in the trailing vortex are calculated from the load distribution on the generating wing, and satisfy a set of fundamental ... Full text Cite

Novel approach to aerodynamic analysis using analytical/numerical matching

Journal Article AIAA Journal · January 1, 1996 Analytical/numerical matching (ANM) is a hybrid scheme combining a low-resolution global numerical solution with a high-resolution local solution to form a composite solution. ANM is applied to lifting surfaces in steady potential flow to calculate the aer ... Full text Cite

Prediction of turbulent trailing vortex structure for rotorcraft blade-vortex interaction

Journal Article Annual Forum Proceedings - American Helicopter Society · December 1, 1995 Accurate knowledge of rotorcraft tip vortex structure is essential to the prediction of rotorcraft free-wake aerodynamics and sound radiation due to blade-vortex interaction. A novel analytical method has been developed to accurately predict the turbulent ... Cite

A novel approach to aerodynamic analysis using analytical/numerical matching

Conference 13th Applied Aerodynamics Conference · January 1, 1995 Analytical/Numerical Matching (ANM) is a hybrid scheme combining a low-resolution global numerical solution with a high-resolution local solution to form a composite solution. ANM is applied to lifting surfaces in steady potential flow to calculate the aer ... Full text Cite

Free vortex calculations using analytical/numerical matching with solution pyramiding

Journal Article AIAA Journal · January 1, 1995 The motion of a free vortex system is predicted using a novel method called analytical/numerical matching (ANM). Analytical/numerical matching is a hybrid mathematical and numerical technique that results in a new problem formulation with high accuracy and ... Full text Cite

Vortex methods for the computational analysis of rotor/body interaction

Journal Article Journal of the American Helicopter Society · January 1, 1994 This paper describes the development and implementation of a unified model of rotorcraft interactional aerodynamics using advanced methods in vortex dynamics. The model incorporates several recently-developed tools for the analysis of vortex wake dynamics ... Full text Cite

Analysis of high resolution unsteady airloads for helicopter rotor blades

Journal Article Annual Forum Proceedings - American Helicopter Society · 1994 The study of helicopter aerodynamic loading for acoustics applications requires the application of efficient yet accurate simulations of the velocity field induced by the rotor's vortex wake. This paper summarizes work to date on the development of such an ... Cite

Direct periodic solutions of rotor free wake calculations

Journal Article Journal of the American Helicopter Society · January 1, 1993 Periodic Inversion is a new approach for the calculation of rotor free wakes which solves directly for periodically steady-state solutions, at all advance ratios including low speed and hover. This is a unique capability as traditional time marching soluti ... Full text Cite

Efficient free wake calculations using analytical/numerical matching

Journal Article Journal of the American Helicopter Society · January 1, 1993 A hybrid analytical and numerical method called analytical/numerical matching is used to calculate the velocity field of rotor wake vortex filaments. A simple discretization of the Biot-Savart law is used to obtain an efficient but low order numerical calc ... Full text Cite

Vortex methods for the computational analysis of rotor/body interaction

Journal Article Annual Forum Proceedings - American Helicopter Society · December 1, 1992 This paper describes the development and implementation of a unified model of rotorcraft interactional aerodynamics using advanced methods in vortex dynamics. The model incorporates several recently-developed tools for the analysis of vortex wake dynamics ... Cite

Application of a two-scale perturbation theory to panel/frame structural-acoustics

Journal Article American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA · December 1, 1991 The analysis of sound transmission across panel/frame structures is important in the design of noise reduction strategies for vehicular interior-noise control. A recently developed two-scale perturbation expansion theory for such problems formulates a comp ... Cite

Prediction of high-resolution flowfields for rotorcraft aeroacoustics

Journal Article AIAA Journal · January 1, 1991 The prediction of noise due to the impingement of the main-rotor wake of a helicopter on the tail rotor and other main-rotor blades requires the efficient computation of the wake-induced velocity field. This paper describes the development of a new treatme ... Full text Cite

Eigenvalue calculation procedure for an Euler/Navier-Stokes solver with application to flows over airfoils

Journal Article Journal of Computational Physics · January 1, 1991 A Lanczos procedure is applied to a Navier-Stokes solver for computing eigenvalues and eigenvectors. These eigenvalues and eigenvectors are associated with small perturbation analysis of a finite difference representation of the Navier-Stokes equations for ... Full text Cite

Role of artificial viscosity in Euler and Navier-Stokes solvers

Journal Article AIAA Journal · January 1, 1991 A method is proposed to determine directly the amount of artificial viscosity needed for stability using an eigenvalue analysis for a finite difference representation of the Navier-Stokes equations. The stability and growth of small perturbations about a s ... Full text Cite

Comparisons of predicted and measured rotor performance in hover using a new free wake analysis

Journal Article Vertica · December 1, 1990 A new free-wake analysis has been developed to predict the performance of rotors in hover and axial flight. The analysis finds the rotor wake geometry using a novel influence coefficient/relaxation scheme. In this paper, the features of the analysis are re ... Cite

Analysis of sound transmission through flexible panel/frame walls

Journal Article American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA · December 1, 1990 Low frequency sound transmission through flexible walls is an important vehicle noise control problem, particularly for aircraft interior noise. The coupled structural/acoustic problem for spatially periodic wall structures is solved using a two-scale pert ... Cite

Free wake flow field calculations for rotorcraft interactional aerodynamics

Journal Article Vertica · December 1, 1990 The principal objective of this work was to explore the applicability of recent innovations in the analysis of vortex dynamics to problems of interest in rotorcraft interactional aerodynamics. Using a novel, full-span rotor wake representation constructed ... Cite

New vortex/surface interaction methods for the prediction of wake-induced airframe loads

Journal Article Annual Forum Proceedings - American Helicopter Society · May 1, 1990 The model incorporates a variety of recently-developed tools for the analysis of vortex dynamics and vortex/surface interaction, including a full-span free wake model of the rotor coupled to a panelled body, as well as new methods for the prediction of sur ... Cite

Direct periodic solutions of rotor free wake calculations by inversion of a linear periodic system

Journal Article Annual Forum Proceedings - American Helicopter Society · May 1, 1990 Periodic Inversion is a new approach for the calculation of rotor free wakes which guarantees periodically steady-state solutions, and provides the means to solve for wake dynamics at all advance ratios including low speed and hover. The method is based on ... Cite

Vortex filament calculations by analytical/numerical matching with comparison to other methods

Conference 9th Computational Fluid Dynamics Conference, 1989 · January 1, 1989 The calculation of fluid velocity from the Biot-Savart law integrated over vortex filaments has traditionally been computationally expensive. Discretizing the filaments into N vortex elements results in order N2 elemental velocity evaluations per time step ... Full text Cite

On the role of artificial viscosity in Navier-Stokes solvers

Conference 9th Computational Fluid Dynamics Conference, 1989 · January 1, 1989 A method is proposed to determine directly the amount of artificial viscosity needed for stability using an eigenvalue analysis for a finite difference representation of the Navier-Stokes equations. The stability and growth of small perturbations about a s ... Full text Cite

New free-wake analysis of rotorcraft hover performance using influence coefficients

Journal Article Journal of Aircraft · January 1, 1989 Free-wake analyses of helicopter rotor wakes in hover using time stepping have been shown to encounter instabilities which preclude convergence to valid free-vortex solutions for rotor-wake geometries. Previous work has demonstrated that these convergence ... Full text Cite

NEW METHODOLOGY FOR FREE WAKE ANALYSIS USING CURVED VORTEX ELEMENTS.

Journal Article · December 1, 1987 A method using curved vortex elements has been developed for helicopter rotor free wake calculations. The Basic Curved Vortex Element (BCVE) is derived from the approximate Biot-Savart integration for a parabolic arc filament. When used in conjunction with ... Cite

ROTOR WAKE MODELING FOR HIGH SPEED APPLICATIONS.

Journal Article Annual Forum Proceedings - American Helicopter Society · December 1, 1987 The effect of various wake models on the prediction of rotor vibratory airloading has been studied in an ongoing research program on wake aerodynamics in high speed flight. At high advance ratios, the rotor wake structure is particularly complicated and th ... Cite

NEW APPROACH TO THE FREE WAKE PROBLEM FOR HOVERING ROTORS.

Journal Article Annual Forum Proceedings - American Helicopter Society · December 1, 1985 A new approach to the free wake problem for a hovering rotor has been developed. An influence coefficient solution method is used to find the rotor wake solution which is steady in a reference frame rotating with the blades. This solution scheme solves dir ... Cite

NEW APPROACH TO THE FREE WAKE PROBLEM FOR HOVERING ROTORS.

Journal Article Annual Forum Proceedings - American Helicopter Society · 1985 A new approach to the free wake problem for a hovering rotor has been developed. An influence coefficient solution method is used to find the rotor wake solution which is steady in a reference frame rotating with the blades. This solution scheme solves dir ... Cite

Wind tunnel wall interference.

Journal Article · January 1, 1984 Studies the behaviour of isolated holes and slots in wind tunnel walls. Uses a potential flow approach to determine the pressure differential/flowrate relationship for various hole planforms in high speed subsonic flow. For low aspect ratio planforms, resu ... Cite

Wind tunnel wall interference.

Journal Article · January 1, 1984 Studies the behaviour of isolated holes and slots in wind tunnel walls. Uses a potential flow approach to determine the pressure differential/flowrate relationship for various hole planforms in high speed subsonic flow. For low aspect ratio planforms, resu ... Cite

Study of bulk reacting porous sound absorbers and a new boundary condition for thin porous layers

Journal Article Journal of the Acoustical Society of America · March 1, 1982 Full text Cite

Experimental investigation of the bulk reaction boundary condition

Journal Article Journal of the Acoustical Society of America · March 1, 1982 A local boundary condition to account for the effect of bulk reaction on the performance of sound absorbing layers was proposed by D. Bliss [J. Acoust. Soc. Am. 71, 533–545 (1982)]. The new boundary condition differs from the usual impedance boundary condi ... Full text Cite

Computational simulation of high speed steady homogeneous two-phase flow in complex piping systems.

Journal Article · January 1, 1982 A study was undertaken to predict steady flow conditions in two-phase steam/water flows in safety/relief discharge piping systems. The approach can also accommodate single phase flows of superheated system of subcooled liquid. Subroutines were developed to ... Cite

Aerodynamic behavior of a slender slot in a wind tunnel wall

Journal Article AIAA Journal · January 1, 1982 A theoretical model for the flow through a single slot of finite length in a wall separating a uniform freestream and a quiescent fluid at different static pressures is constructed. This problem is relevant to understanding the aerodynamic behavior of slot ... Full text Cite

Effect of unsteady forcing on the sinusoidal instability of vortex wakes

Journal Article Journal of Aircraft · January 1, 1982 An analytical model of the vortex wake instability subject to forcing by unsteady lift fluctuations has been developed. These lift fluctuations can be caused either by variations in angle of attack or by flying through atmospheric turbulence. The effect of ... Full text Cite

Computational simulation of high speed steady homogeneous two-phase flow in complex piping systems.

Journal Article · January 1, 1982 A study was undertaken to predict steady flow conditions in two-phase steam/water flows in safety/relief discharge piping systems. The approach can also accommodate single phase flows of superheated system of subcooled liquid. Subroutines were developed to ... Cite

Computational simulation of high-speed steady homogeneous two-phase flow in complex piping systems

Journal Article Journal of Pressure Vessel Technology, Transactions of the ASME · January 1, 1982 A study was undertaken to predict steady flow conditions in two-phase steam/water flows in safety/relief discharge piping systems. The homogeneous-equilibrium model was used for the two-phase flow along with the ASME Steam Tables in subroutine form as a st ... Full text Cite

Absorption material mounted on a moving wall-Fluid/wall boundary condition

Journal Article J. Acoust. Soc. Am. (USA) · 1981 The case of a structural (elastic) wall on which is mounted an absorptive material does not appear to have a self-consistent derivation of a physically correct boundary condition. Such a derivation is the authors' goal ... Cite

MODAL ANALYSIS OF INTERIOR NOISE FIELDS.

Journal Article Semiconductor International · January 1, 1981 E. H. Dowell's linear theory of acoustoelasticity, which is capable of predicting the interior sound field for any structural model surrounding an arbitrarily shaped acoustic cavity subject to a prescribed internal sound source and/or external noise fields ... Cite

ACOUSTOELASTICITY: REVIEW AND EXTENSION.

Journal Article Ammonia Plant Safety (and Related Facilities) · January 1, 1980 The paper discusses the interaction between the (acoustic) sound pressure field and the (elastic) flexible wall of an enclosure. Such problems frequently arise when the vibrating walls of a transportation vehicle induce a significant internal sound field. ... Cite

Prediction of wind responses of tall open truss structures

Journal Article S V Sound and Vibration · October 1, 1974 This article summarizes the salient aspects of the wind forces, including their spatial and temporal distributions, outlines a response calculation approach, suggests a method for selecting a design value for the maximum expected modal displacement, and pr ... Cite

The instability of short waves on a vortex ring

Journal Article Journal of Fluid Mechanics · January 1, 1974 A simple model for the experimentally observed instability of the vortex ring to azimuthal bending waves of wavelength comparable with the core size is presented. Short-wave instabilities are discussed for both the vortex ring and the vortex pair. Instabil ... Full text Cite

SELF-INDUCED MOTION AND STABILITY OF CONCENTRATED VORTEX FILAMENTS

Journal Article · January 1, 1974 THE SELF-INDUCED MOTION AND STABILITY OF VORTEX FILAMENTS WAS INVESTIGATED BOTH THEORETICALLY AND EXPERIMENTALLY.THOUGH AN APPLICATION OF THE METHOD OF MATCHED ASYMPTOTIC EXPANSIONS, A GENERAL SOLUTION IS OBTAINED FOR THE SELF-INDUCED MOTION OF A VORTEX FI ... Cite

SELF-INDUCED MOTION AND STABILITY OF CONCENTRATED VORTEX FILAMENTS.

Journal Article Arch Mech - Arch Mech Stosow · January 1, 1974 The self-induced motion and stability of vortex filaments is investigated both theoretically and experimentally. Through an application of the method of matched asymptotic expansions, a general solution is obtained for the self-induced motion of a vortex f ... Cite

INSTABILITY OF SHORT WAVES ON A VORTEX RING.

Journal Article Journal of Fluid Mechanics · 1974 A simple model for the experimentally observed instability of the vortex ring to azimuthal bending waves of wavelength comparable with the core size is presented. Short-wave instabilities are discussed for both the vortex ring and the vortex pair. Instabil ... Cite

SELF-INDUCED MOTION AND STABILITY OF CONCENTRATED VORTEX FILAMENTS

Journal Article · January 1, 1974 THE SELF-INDUCED MOTION AND STABILITY OF VORTEX FILAMENTS WAS INVESTIGATED BOTH THEORETICALLY AND EXPERIMENTALLY.THOUGH AN APPLICATION OF THE METHOD OF MATCHED ASYMPTOTIC EXPANSIONS, A GENERAL SOLUTION IS OBTAINED FOR THE SELF-INDUCED MOTION OF A VORTEX FI ... Cite

Slender-body analysis of the motion and stability of a vortex filament containing an axial flow

Journal Article J. Fluid Mech. (UK) · 1971 Results concerning the effects of axial velocity on the motion of vortex filaments are reviewed. These results suggest that a slender body force balance between the Kutta-Joukowski lift on the vortex cross-section and the momentum flux within the curved fi ... Cite

Time sharing-powerful tool for small shops

Journal Article Tool Manuf. Eng. (USA) · 1969 Discusses the development of a low-cost remote-access terminal for a time-shared computer which extends engineering and decision making capabilities of the small job shop. Tape preparation for numerically controlled machine tools is among the topics discus ... Cite