SUPERSONIC/HYPERSONIC UNSTEADY AERODYNAMIC ANALYSIS OF A WEDGE-TYPE AIRFOIL USING NONLINEAR PISTON THEORY AND EULER EQUATIONS

비선형 피스톤 이론과 오일러 방정식을 이용한 쐐기형 에어포일의 초음속/극초음속 비정상 공력해석

In this study, unsteady aerodynamic analyses of a wedge-type airfoil based on nonlinear piston theory and Euler equations have been performed in supersonic and hypersonic flows. The third-order nonlinear piston theory (NPT) to calculate unsteady lift and moment coefficients is derived and applied in the time-domain. Also, unsteady flow quantities are obtained from the two-dimensional time-dependent Euler equations. For the CFD based unsteady aerodynamic analyses, an arbitrary Lagrangean-Eulerian (ALE) formulation for the Euler equations is used to calculate flow fluxes in the computational flow field with moving boundaries. Numerical comparisons for unsteady lift and moment coefficients are presented between NPT and Euler approaches. The results show very good agreements in the high supersonic and hypersonic flows. It means that the present NPT can be efficiently used to predict unsteady aerodynamic forces ol wedge type airfoils with dynamic motions in the high supersonic and hypersonic flow regimes.