Unsteady numerical simulation of propeller slipstream based on unstructured chimera grid

Abstract

Numerical simulations of unsteady Reynolds averaged Navier-Stokes (URANS) equations were conducted for isolated-propeller and turboprops configurations based on anisotropic unstructured chimera grids. Walls criterion was used in the automatic hole-cutting procedure. Distance weight interpolation and tri-linear interpolation were developed to transmit variable value. The computation grids contained rotational subzone of propeller and stationary subzone of aircraft. The boundaries of chimera grids were optimized for fixed axis rotation. The equations were solved by dual-time method and lower upper-symmetric Gauss-Seidel (LU-SGS). The method and grid technology were validated by isolated-propeller and the computation results were compared with experimental data, showing good agreement with each other. Then turboprops configuration was simulated and the aerodynamic characteristics of aircraft with or without slipstream were compared. The effect of slipstream was analyzed by surface pressure and pressure distribution of sections. The results indicated that the slipstream increased drag and pitching moment coefficient. Slipstream affected the pressure distributions of wing and flat-tail, causing the airflow downwash.