High-speed inlet unstart calculations using an implicit solution adaptive mesh algorithm

Abstract

Time accurate high-speed flow calculations using a three-dimensional adaptive mesh algorithm with a time accurate implicit Navier-Stokes solver are presented in this work. A dynamic grid adaptation algorithm is developed which improves grid orthogonality near boundaries allowing the accurate resolution of both high-Reynolds number turbulent boundary layers and complex inviscid flow features. This is achieved by using a skewness factor raised to an orthogonality factor (magnitude of face unit normal dot product) as coefficients in the grid point movement algorithm. Steadystate calculations of a three-dimensional inlet/isolator flowfield are presented to highlight the ability of the adaptive mesh algorithm to resolve complex flow features. A three-dimensional inlet unstart due to a combustor perturbation is simulated by closing a diffuser ramp which raises exit pressure. The computational results demonstrate the ability to calculate 3-D highspeed inlet unstarts with a solution adaptive mesh algo-