Analytic Sensitivities and Approximations in Supersonic and Subsonic Wing/Control Surface Unsteady Aerodynamics

Development of efe cient, design-oriented analysis techniques and associated approximations for wing/ control surface unsteady aerodynamics is crucial to the success of any multidisciplinary aeroservoelastic optimization of airplanes including active control technology. A design-oriented capability for unsteady supersonic aerodynamics for planar wing/control surface cone gurations is presented here. Explicit expressions for aerodynamic ine uence coefe cients make it possible to efe ciently obtain analytic sensitivities of generalized aerodynamic loads with respect to planform shape. Examination of the mathematical structure of the discretization used, similar to other aerodynamic panel methods, reveals sources of discontinuity of derivatives with respect to shape in the supersonic case. Sources of nonsmooth behavior of the unsteady aerodynamic loads in subsonic e ow are identie ed and eliminated. The accuracy and computational cost of alternative approximation techniques are studied. A second-order approximation technique based on the direct and adjoint solutions at a reference cone guration is presented. Experience and insight are gained in the area of design-oriented and approximate unsteady aerodynamics, to be used in the nonlinear programming/approximation concepts approach to engineering optimization.

[1]  Raphael T. Haftka,et al.  On repetitive flutter calculations in structural design , 1974 .

[2]  Thomas E. Noll,et al.  Active Flexible Wing Program , 1995 .

[3]  Danny D. Liu,et al.  Unsteady subsonic aerodynamics for bodies and wings with external stores including wake effect , 1993 .

[4]  Bernard Grossman,et al.  Noisy Aerodynamic Response and Smooth Approximations in HSCT Design , 1994 .

[5]  T. Ueda.  Expansion series of integral functions occurring in unsteady aerodynamics , 1982 .

[6]  Peretz P. Friedmann,et al.  Towards integrated multidisciplinary synthesis of actively controlled fiber composite wings , 1990 .

[7]  Terry Harris,et al.  Impact of active controls technology on structural integrity , 1993 .

[8]  Jinsoo Cho,et al.  S-plane aerodynamics of nonplanar lifting surfaces , 1993 .

[9]  E. Livne,et al.  Aeroservoelastic aspects of wing/control surface planform shape optimization , 1995 .

[10]  O. Sensburg,et al.  COMPATIBILITY ASPECTS OF ACTIVE CONTROL TECHNOLOGIES WITH AIRCRAFT STRUCTURE DESIGN , 1987 .

[11]  Raphael T. Haftka,et al.  Recent Advances in Approximation Concepts for Optimum Structural Design , 1993 .

[12]  V. Stark.  On the approximation of the normal velocity on oscillating wings. , 1966 .

[13]  E. Livne,et al.  Exploratory design studies using an integrated multidisciplinary synthesis capability for actively controlled composite wings , 1990 .

[14]  Peretz P. Friedmann,et al.  Exploratory Design Studies of Actively Controlled Wings Using Integrated Multidisciplinary Synthesis , 1992 .

[15]  Inderjit Chopra,et al.  Multidisciplinary Optimization of Aeronautical Systems , 1990 .

[16]  Earl H. Dowell,et al.  Doublet-Point Method for Supersonic Unsteady Lifting Surfaces. , 1984 .

[17]  Earl H. Dowell,et al.  A New Solution Method for Lifting Surfaces in Subsonic Flow , 1982 .

[18]  K. Appa,et al.  Constant pressure panel method for supersonic unsteady airload analysis , 1987 .

[19]  K. L. Roger,et al.  Airplane Math Modeling Methods for Active Control Design , 1977 .

[20]  Walter Eversman,et al.  Hybrid doublet lattice/doublet point method for lifting surfaces in subsonic flow , 1991 .

[21]  E. Carson Yates,et al.  Aerodynamic sensitivities from subsonic, sonic and supersonic unsteady, nonplanar lifting-surface theory , 1987 .

[22]  D. Liu,et al.  Unsteady supersonic computations of arbitrary wing-body configurations including external stores , 1988 .

[23]  E. Nissim,et al.  Supersonic three-dimensional oscillatory piecewise continuous kernelfunction method , 1983 .

[24]  E. Carson Yates.  Integral-equation methods in steady and unsteady subsonic, transonic, and supersonic aerodynamics for interdisciplinary design , 1993 .

[25]  R. Haftka,et al.  Elements of Structural Optimization , 1984 .

[26]  A. M. Cunningham,et al.  Oscillatory supersonic kernel function method for interfering surfaces , 1974 .

[27]  B. V. Niekerk.  Computation of Second-Order Accurate Unsteady Aerodynamic Generalized Forces , 1986 .

[28]  Eli Livne,et al.  Equivalent plate structural modeling for wing shape optimization including transverse shear , 1994 .

[29]  L. Schmit,et al.  Integrated aeroservoelastic wing synthesis by nonlinear programming/approximation concepts , 1992 .

[30]  E. Livne.  Alternative Approximations for Integrated Control/Structure Aeroservoelastic Synthesis , 1993 .