An efficient approach for calculation of pitching moment in nonlinear reduced frequency method at low Mach number transonic flows

Abstract

SUMMARYIn this research, an efficient methodology for calculation of pitching moment coefficient at low Mach number transonic flows by using the perturbed nonlinear reduced frequency approach is presented. The proposed approach uses the perturbation technique in the nonlinear frequency domain (NLFD) method to estimate the solution at high harmonics. In this approach, the density and velocity fields at high harmonics are perturbed about those at low harmonics. Perturbing the density and velocity fields, the semi-linear form of the governing equations is obtained. The resulting solution vector and spatial operator are then approximated by discrete form of Fourier transformation and governing equations are solved by using the pseudo-spectral approach. Numerical results show that the proposed approach predicts good pitching moment coefficient at low Mach number transonic flows with up to 50% savings in computational time.

Time-periodic incompressible flow simulation using non-linear frequency domain approach

“…Kharati et al [25,26] have also used perturbation technique in nonlinear frequency domain method to estimate the solution at high harmonics in transonic flows. The density and velocity field at high harmonics are perturbed about those of low harmonics to form semilinear governing equations.…”