4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III最新文献

Multidisciplinary Optimization of Composite Wings Using Refined Structural and Aeroelastic Analysis Methodologies 基于精细结构和气动弹性分析方法的复合材料机翼多学科优化

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1080/03052159908941291

R. Jha, A. Chattopadhyay

{"title":"Multidisciplinary Optimization of Composite Wings Using Refined Structural and Aeroelastic Analysis Methodologies","authors":"R. Jha, A. Chattopadhyay","doi":"10.1080/03052159908941291","DOIUrl":"https://doi.org/10.1080/03052159908941291","url":null,"abstract":"\u0000 An integrated multidisciplinary procedure has been developed for structural and aeroelastic optimization of composite wings based on refined analysis technique. A refined higher-order theory is used to analyze composite box beam, which represents the load carrying member of the wing. Unsteady aerodynamic computations are performed using a panel code based on the Doublet Lattice Method. Flutter/divergence dynamic pressure is obtained by the Laplace domain method through rational function approximation of unsteady aerodynamic loads. The objective of the optimization procedure is to minimize wing structural weight with constraints on flutter/divergence speed and stresses at the root due to the static load. Composite ply orientations and laminate thicknesses are used as design variables. The Kreisselmeier-Steinhauser function approach is used to efficiently integrate the objective function and constraints into a single envelope function. The resulting unconstrained optimization problem is solved using the Davidon-Fletcher-Powell algorithm. Numerical results are presented showing significant improvements, after optimization, compared to a reference design.","PeriodicalId":166345,"journal":{"name":"4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115509834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Two- and Three-Dimensional Analyses of Flow Around Airfoils Subjected to Forced Oscillation 受强迫振荡影响的翼型绕流的二维和三维分析

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0170

Y. Yokono

{"title":"Two- and Three-Dimensional Analyses of Flow Around Airfoils Subjected to Forced Oscillation","authors":"Y. Yokono","doi":"10.1115/imece1997-0170","DOIUrl":"https://doi.org/10.1115/imece1997-0170","url":null,"abstract":"\u0000 This paper describes extensive computer-based analytical studies on the details of unsteady flow behavior around oscillating airfoils in turbomachinery. To consider the time-dependent motions of airfoils, a complete Navier-Stokes solver incorporating a moving mesh was applied, and the drag and lift coefficients for the cases of stationary airfoils and airfoils subjected to forced oscillation were examined. In order to clarify the interaction between the airfoil structure and the flow induced force, the exact fluctuation of the drag and lift coefficients with time needed to be determined. Although two-dimensional analyses have been performed for two-dimensional airfoils, it has suggested to be difficult to obtain the true separation vortex in such analyses because the vortex structure is essentially three-dimensional. Therefore, in the present study, a comparison was made between the two- and three-dimensional analyses for NACA0012 airfoils, and the separation vortex structure was examined in detail.\u0000 From the numerical results, it was found that the separation vortex consisted of large-scale rolls with axes in the span direction, and rib substructures with axes in the stream direction. The three-dimensional analysis could simulate these rolls and ribs, but the two-dimensional analysis was inadequate to realize this vortex structure. This is the main difference between the two- and three-dimensional analyses. In addition, the formation of ribs was found to be affected by the forced oscillation, and the transformation of rolls increased and the vortex structure became more fine as the oscillation frequency increased.","PeriodicalId":166345,"journal":{"name":"4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124322603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Serial and Parallel Fast-Floquet Analyses in Rotorcraft Aeroelasticity 旋翼机气动弹性的串行和并行快速小波分析

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0158

S. Subramanian, S. Venkataratnam, G. Gaonkar

{"title":"Serial and Parallel Fast-Floquet Analyses in Rotorcraft Aeroelasticity","authors":"S. Subramanian, S. Venkataratnam, G. Gaonkar","doi":"10.1115/imece1997-0158","DOIUrl":"https://doi.org/10.1115/imece1997-0158","url":null,"abstract":"Rotorcraft stability investigation involves a nonlinear trim analysis for the control inputs and periodic responses, and, as a follow-up, a linearized stability analysis for the Floquet transition matrix (FTM), and its eigenvalues and eigenvectors. The trim analysis is based on a shooting method with damped Newton iteration, which gives the FTM as a byproduct, and the eigenanalysis on the QR method; the corresponding trim and stability analyses are collectively referred to as the Floquet analysis. A rotor with Q blades that are identical and equally spaced has Q planes of symmetry. Exploiting this symmetry, the fast-Floquet analysis, in principle, reduces the run time and frequency indeterminacy of the conventional Floquet analysis by a factor of Q. It is implemented on serial computers and on all three types of mainstream parallel-computing hardware: SIMD and MIMD computers, and a distributed computing system of networked workstations; large models with hundreds of states are treated. A comprehensive database is presented on computational reliability such as the eigenvalue condition number and on parallel performance such as the speedup and efficiency, which show, respectively, how fast a job can be completed with a set of processors and how well their idle times are minimized. Despite the Q-fold reduction, the serial run time is excessive and grows between quadratically and cubically with the number of states. By contrast, the parallel run time can be reduced dramatically and its growth can be controlled by a judicious combination of speedup and efficiency. Moreover, the parallel implementation on a distributed computing system is as routine as the serial implementation.","PeriodicalId":166345,"journal":{"name":"4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III","volume":"136 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114926331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unsteady Aeroelastic Simulations for Airfoils 非定常翼型气动弹性模拟

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0164

E. Guilmineau, P. Queutey

引用次数: 0

Re-Engineering of an Aeroelastic Code for Solving Eigen Problems in All Flight Regimes 求解所有飞行状态下特征问题的气动弹性代码的再工程

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0171

M. Lesoinne, C. Farhat

引用次数: 2

Fluid-Structure Coupling Requirements for Time-Accurate Aeroelastic Simulations 时间精确气动弹性模拟的流固耦合要求

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0161

O. Bendiksen

{"title":"Fluid-Structure Coupling Requirements for Time-Accurate Aeroelastic Simulations","authors":"O. Bendiksen","doi":"10.1115/imece1997-0161","DOIUrl":"https://doi.org/10.1115/imece1997-0161","url":null,"abstract":"\u0000 In this paper we study the requirements that must be satisfied by a fluid-structure coupling scheme, in order to obtain a dynamically consistent aeroelastic code. Both spatial compatibility and time synchronization requirements must be met, to assure that the time-marching simulations exhibit the physically correct stability behavior. Inconsistent or inaccurate implementation of the fluid-structure boundary conditions can cause the aeroelastic code to converge to an incorrect aeroelastic solution. It is shown that CFD codes based on linear interpolations for the velocities cannot be fully compatible with structural FE codes that use plate or shell elements to model the wing skin. Numerical examples are presented for three different nonlinear aeroelastic models, using Euler-based aerodynamics and two different fluid-structure coupling schemes. The results indicate that for Mach numbers in the upper transonic range, past the transonic dip, the aeroelastic solution appears very sensitive to the fluid-structure coupling scheme used. In the case of the NACA 0012 model, the two different schemes studied predicted entirely different stability behaviors.","PeriodicalId":166345,"journal":{"name":"4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114798452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Modeling and Aeroelasticity of Advanced Aircraft Wings Carrying External Stores 先进飞机机翼承载外挂材料的建模与气动弹性

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0169

F. Gern, L. Librescu

引用次数: 0

Parametric Vibration of Elastic Cavitating Wing in Unsteady Flow 非定常流场弹性空化翼的参数振动

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0163

S. Kovinskaya, E. Amromin

{"title":"Parametric Vibration of Elastic Cavitating Wing in Unsteady Flow","authors":"S. Kovinskaya, E. Amromin","doi":"10.1115/imece1997-0163","DOIUrl":"https://doi.org/10.1115/imece1997-0163","url":null,"abstract":"\u0000 A two-dimensional unsteady potential flow outside an elastic partially cavitating wing is analyzed numerically by using the Birnbaum equation on hydrofoil chord and the Lagrange-Cauchy integral on the cavity. An angle of attack has a small periodic perturbation, and cavity thickness and length have got perturbations too. Wing vibration is considered as vibration of a variable thickness beam with two clamp bolts near the beam center. A mono-frequency flow perturbation induces mono-frequency flexural vibration of a non-cavitating wing, but the vibration of a cavitating wing is multy-frequency one, and a spectrum of a cavitating wing response can depend on an amplitude of the incoming flow perturbation.\u0000 Numerical simulation of NACA-16009 hydrofoil vibration was made for various free-stream speeds, module of elasticity, fluid and wing densities, and as a result, three frequency bands of a vibration increase are found. The low-frequency band is connected with a cavity volume oscillation. There is a considerable effect of cavity length, therefore the cavitation number influences on vibration as a parameter. The high-frequency band is connected with elastic resonances of wing. Besides, resonance-like frequencies were found in the middle band. This phenomenon has not a dependence on cavity dimensions and wing elasticity, but appears as a result of an interaction between hydrodynamic damping and media inertia forces.","PeriodicalId":166345,"journal":{"name":"4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121882604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Extension of Dynamic Wake Models for Moderate to High Reduced Frequencies 中高降频动态尾迹模型的扩展

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1115/imece1997-0157

D. Peters, S. Karunamoorthy, Michael Sobol

引用次数: 0

Dynamics of Nonlinear Aeroelastic Systems 非线性气动弹性系统动力学

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III Pub Date : 1997-11-16 DOI: 10.1061/(ASCE)0893-1321(1998)11:2(59)

N. Namachchivaya, A. Lee

{"title":"Dynamics of Nonlinear Aeroelastic Systems","authors":"N. Namachchivaya, A. Lee","doi":"10.1061/(ASCE)0893-1321(1998)11:2(59)","DOIUrl":"https://doi.org/10.1061/(ASCE)0893-1321(1998)11:2(59)","url":null,"abstract":"\u0000 This paper investigates the effects of nonlinearities on the dynamics of flat panels in supersonic flow and presents new bifurcation results for a fairly general nonlinear aeroelastic system. In order to obtain these results we use the method of normal forms, global bifurcation techniques, and various other dynamical systems tools. The first part of this paper deals with modeling unsteady aerodynamic forces and moments acting on flat panels undergoing arbitrary motion in supersonic flow. This modeling also considers the structural nonlinearities inherent in panels. While deriving the equations of motion, many in the past have neglected some nonlinear aerodynamic terms as insignificant from the modeling point of view. However, inclusion of these terms in the analysis may completely change the bifurcation behavior. In aeroelastic systems it is the nonlinear dissipative terms that can change the behavior, and it is essential to carefully model these terms in the physical problems. In the absence of dissipative terms the nonlinear system is reversible, which provides the governing equations with near integrable structure. Thus certain analytical methods are used to study the bifurcation behavior of the system near critical points. For general nonlinear fiat panels in supersonic flow, we present these effects as various bifurcation results due to symmetry-breaking imperfections. For aeroelastic systems, the reversible symmetry is broken by the addition of unsteady aerodynamic terms.","PeriodicalId":166345,"journal":{"name":"4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume III","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129342575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4