Current status of computational methods for transonic unsteady aerodynamics and aeroelastic applications

Edwards, John W.; Malone, John B.

doi:10.1016/0956-0521(92)90025-e

Cited by 33 publications

(17 citation statements)

References 50 publications

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“…(7) can be generatedby applyingEq. (8) to ve basic modes, namely, the plunge, pitch, leading-edge ap, trailing-edge ap, and chordwise bending modes. Again, we note that the choice of a ve basic-mode combinationhere is only a special practice of the general modal AIC formulations, Eqs.…”

Section: Transonic Equivalent Strip Methods and Transonic Aicmentioning

confidence: 99%

“…Thus, the current treatment in the unsteady transonics/hypersonics mostly adopts the computational uid dynamics (CFD) methodology. Currently there exist a number of well-practicedCFD unsteadytransonicmethods 8,9 ready for aeroelastic applications.However, their acceptance by the aerospace industry for rapid analysis and design is hampered by problems in grid generation,CFD/computationalstructural dynamics interfacing,and affordablecomputingtime. Their furtherintegration into an MDO environment such as ASTROS 10,11 is somewhat discouraged by their incompatibility with the structural FEM.…”

Section: Introductionmentioning

confidence: 99%

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Transonic-Aerodynamic-Influence-Coefficient Approach for Aeroelastic and MDO Applications

Chen

Sarhaddi

Liu

2000

Journal of Aircraft

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A developed transonic-aerodynamic-in uence-coef cient (TAIC) method is proposed as an ef cient tool for applications to utter, aeroservoelasticity, and multidisciplinary design/analysis optimization. Several plausible procedures for AIC generation are described. The modal-based AIC procedure is formally established as a general AIC scheme applicable to all classes of computational uid dynamics (CFD) methods. The present TAIC method integrates the previous transonic equivalent strip (TES) method with the modal AIC approach; its computer code ZTAIC has a similar input format to that of doublet lattice method (DLM) except with the additional steady pressure input. The versatility of ZTAIC is shown by two sets of cases studied: those cases with pressure input from measured data and those from CFD computation. Computed results of unsteady pressures and utter points are presented for six wing planforms. In contrast to the usual CFD practice, the effective use of the modal AIC in ZTAIC is clearly demonstrated by the utter calculations of the weakened and solid 445.6 wings, where the CPU time of a transonic utter point using warm-started AIC is less than 1 min on a SUN SPARC20 workstation. Moreover, the AIC capability allows ZTAIC to be readily integrated with structural nite element method (FEM). Hence, it is most suitable to be adopted in a multidisciplinary design (MDO) environment such as ASTROS.

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Section: Transonic Equivalent Strip Methods and Transonic Aicmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transonic-Aerodynamic-Influence-Coefficient Approach for Aeroelastic and MDO Applications

Chen

Sarhaddi

Liu

2000

Journal of Aircraft

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“…Because of their relative computational efficiency, the transonic small distur-bance (TSD) equation and the full potential (FP) equation have been applied to a wider variety of three-dimensional configurations than the Euler and Naiver-Stokes equations. 2 Similarly, the TSD and FP equations also have been utilized for more detailed analyses of the aeroelastic characteristics of these configurations. In contrast, the higher-order methods, such as the Euler and Navier-Stokes equations, typically have been applied to the analyses of flexible wings over a limited range of flow conditions.…”

mentioning

confidence: 99%

“…to more recent applications of the Euler and Navier-Stokes equations for the aeroelastic analysis of three-dimensional wings, the field of computational aeroelasticity has progressed rapidly. 2 With the advent of more powerful computers and more efficient algorithms, researchers have in recent years computed more detailed and sophisticated simulations of aeroelastic phenomena. Because of their relative computational efficiency, the transonic small distur-bance (TSD) equation and the full potential (FP) equation have been applied to a wider variety of three-dimensional configurations than the Euler and Naiver-Stokes equations.…”

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confidence: 99%

Calculation of AGARD Wing 445.6 flutter using Navier-Stokes aerodynamics

Elizabeth

John

1993

11th Applied Aerodynamics Conference

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The flutter characteristics of the first AGARD standard aeroelastic configuration for dynamic response, Wing 445.6, are studied using an unsteady Navier-Stokes algorithm in order to investigate a previously noted discrepancy between Euler flutter characteristics and the experimental data. The algorithm, which is a three-dimensional, implicit, upwind Euler/Navier-Stokes code (CFL3D Version 2.1), was previously modified for the time-marching, aeroelastic analysis of wings using the unsteady Euler equations. These modifications include the incorporation of a deforming mesh algorithm and the addition of the structural equations of motion for their simultaneous time integration with the governing flow equations. In this paper, the aeroelastic method is extended and evaluated for applications that use the NavierStokes aerodynamics. The paper presents a brief description of the aeroelastic method and presents unsteady calculations which verify this method for Navier-Stokes calculations. A linear stability analysis and a time-marching aeroelastic analysis are used to determine the flutter characteristics of the isolated 45 swept-back wing. Effects of fluid viscosity, structural damping, and number of modes in the structural model are investigated. For the linear stability analysis, the unsteady generalized aerodynamic forces of the wing are computed for a range of reduced frequencies using the pulse transfer-function approach. The flutter characteristics of the wing are determined using these unsteady generalized aerodynamic forces in a traditional V-g analysis. This stability analysis is used to determine the flutter characteristics of the wing at free-stream Mach numbers of 0.96 and 1.141 using the generalized aerodynamic forces generated by solving the Euler equations and the Navier-Stokes equations. Time-marching aeroelastic calculations are performed at a free-stream Mach number of 1.141 using the Euler and Navier-Stokes equations to compare with the linear V-g flutter analysis method. The V-g analysis, which is used in conjunction with the time-marching analysis, indicates that the fluid viscosity has a significant effect on the

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“…The ma- jority of work in unsteady CFD has, however, been restricted to small amplitude, harmonic variations in angle of attack in support of aeroelastic utter predictions. 8 The objective of the present work is to apply unsteady CFD methods to the problem of predicting VTVL vehicle aerodynamics during an un-powered pitch-over maneuver. The inviscid 3D3U code of Batina 9 is employed to solve the 3-D unsteady oweld with unstructured grids.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic characteristics of an aerospace vehicle during a subsonic pitch-over maneuver

William

1996

34th Aerospace Sciences Meeting and Exhibit

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Time-dependent CFD has been used to predict aerospace vehicle aerodynamics during a subsonic rotation maneuver. The inviscid 3D3U code is employed to solve the 3-D unsteady oweld using an unstructured grid of tetrahedra. As this application represents a challenge to time-dependent CFD, observations concerning spatial and temporal resolution are included. It is shown that even for a benign rotation rate, unsteady aerodynamic eects are signicant during the maneuver. Possibly more signicant, however, the rotation maneuver creates ow asymmetries leading to yawing moment, rolling moment, and side force which are not present in the quasi-steady case. A series of steady solutions at discrete points in the maneuver are also computed for comparison with wind tunnel measurements and as a means of quantifying unsteady eects.

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Current status of computational methods for transonic unsteady aerodynamics and aeroelastic applications

Cited by 33 publications

References 50 publications

Transonic-Aerodynamic-Influence-Coefficient Approach for Aeroelastic and MDO Applications

Transonic-Aerodynamic-Influence-Coefficient Approach for Aeroelastic and MDO Applications

Calculation of AGARD Wing 445.6 flutter using Navier-Stokes aerodynamics

Aerodynamic characteristics of an aerospace vehicle during a subsonic pitch-over maneuver

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