Supersonic indicial lift functions from transform methods

An alternative method to evaluate the classical linear indicial lift of airfoil downwash distribution in supersonic flow, derive the indical lift functions, and reduce the transient lift to quadrature, is discussed. The transient at short times to steady-state solutions is carried out for zeroth-to-cubic-order polynomial functions and the aerodynamic loads of simply supported panel-flutter are presented and compared with analytic polynomial approximations. The results show that the airfoil downwash is impulsively changed at t=0 and remains time-invariant for t≮0. The panel-flutter mode is approximated as a quadratic downwash description by matching the steady-state lift values and having simple analytic expressions for polynomial approximation and the exact panel-mode shape.

Duke Scholars

Author Earl H. Dowell Thomas Lord Department of Mechanical Engineering and Materia ...