Solution of the unsteady Euler equations for fixed and rotor wing configurations

A solution procedure is described for the numerical solution of inviscid rotational flow past fixed and rotor wing configurations. This procedure solves the three-dimensional Euler equations in a body-fitted coordinate system and strong conservation form. The derivatives along the spanwise direction are lagged by one time step, while all the other terms are treated in a fully implicit manner. This leads to a semi-implicit scheme that requires two block tridiagonal matrix inversions and one residual evaluation per point at every time step. This procedure also requires the flow variables to be stored at only one time level. A number of fixed wing and rotor wing calculations are presented to demonstrate the efficiency and accuracy of this procedure.