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is actively engaged in research on hypersonic aeroelasticity and aerothermoelasticity, multidisciplinary analysis and control of hypersonic vehicles, wind turbine aerodynamics and aeroelasticity, and turbomachinery aeromechanics. His research in hypersonic aeroelasticity and aerothermoelasticity was recognized with the 2004 ASME/Boeing Structures and Materials Award. He is currently a Senior Member of the AIAA.

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The testing of aeroelastically and aerothermoelastically scaled wind-tunnel models in hypersonic flow is not feasible; thus, computational aeroelasticity and aerothermoelasticity are essential to the development of hypersonic vehicles. Several fundamental issues in this area are examined by performing a systematic computational study of the hypersonic aeroelastic and aerothermoelastic behavior of a three-dimensional configuration. Specifically, the flutter boundary of a low-aspect-ratio wing, representative of a fin or control surface on a hypersonic vehicle, is studied over a range of altitudes using third-order piston theory and Euler and Navier-Stokes aerodynamics. The sensitivity of the computational-fluid-dynamics-based aeroelastic analysis to grid resolution and parameters governing temporal accuracy are considered. In general, good agreement at moderate-to-high altitudes was observed for the three aerodynamic models. However, the wing flutters at unrealistic Mach numbers in the absence of aerodynamic heating. Therefore, because aerodynamic heating is an inherent feature of hypersonic flight and the aeroelastic behavior of a vehicle is sensitive to structural variations caused by heating, an aerothermoelastic methodology is developed that incorporates the heat transfer between the fluid and structure based on computational-fluid-dynamics-generated aerodynamic heating. The aerothermoelastic solution procedure is then applied to the low-aspect-ratio wing operating on a representative hypersonic trajectory. In the latter study, the sensitivity of the flutter margin to perturbations in trajectory angle of attack and Mach number is considered. Significant reductions in the flutter boundary of the heated wing are observed. The wing is also found to be susceptible to thermal buckling. Nomenclature a 1 = speed of sound C L , C M , C D = coefficients of lift and moment about the elastic axis and drag C p = coefficient of pressure CFL = Courant-Friedrichs-Lewy three-dimensional input parameter regulating pseudo-time-step size C w = Chapman-Rubesin coefficient c = reference chord length of the double-wedge airfoil c pw = specific heat of the wall h ht = heat-transfer coefficient k ! = reduced frequency M = freestream Mach number M, K = generalized mass and stiffness matrices of the structure M f = flutter Mach number n = normal vector n m= number of modes p = pressure p 1 = freestream pressure Q = generalized force vector for the structure= heat-transfer rate due to aerodynamic heating, radiation, conduction, and stored energy q i = modal amplitude of mode i q vf = virtual-flutter dynamic pressure q 1 = dynamic pressure Re = Reynolds number S = surface area of the structure T = temperature T AW = adiabatic-wall temperature T E = kinetic energy of the structure T R = radiation equilibrium wall temperature= potential energy of the structure V = freestream velocity v n = normal velocity of airfoil surfaces w = displacement of the surface of the structure x, y, z = spatial coordinates y = law-of-the-wall coordinate Zx; y;...