Comparisons of steady and unsteady methods for pitch-damping predictions

Abstract

A prediction method for the pitch-damping force and moment coefficients is presented in the unified framework of the unsteady Navier-Stokes equations with the k-omega turbulence equations. This approach does not require modification of the governing equations except addition of non-inertial force terms. The present method is applied to compute the pitch-damping coefficients using the lunar coning and the zero-spin coning motions in the Cartesian coordinate framework. Grid refinement and parametric studies are performed for the ANSR and the Basic Finner, The results for the pitch-damping coefficients and Magnus moment coefficients are compared with the PNS data and the results using the unsteady method. The variety of the computational results is in good agreement with the PNS data and range data. The results show that the steady approach using the unified governing equations in the Cartesian coordinate frame can be successfully applied to predict the pitch-damping coefficients.