Investigation on Propeller Slipstream by Using an Unstructured Rans Solver Based on Overlapping Grids

Abstract

Based on unstructured hybrid grid and dynamic overlapping grid technique, numerical simulations of Unsteady Reynolds Averaged Navier-Stokes equations were performed and investigation on isolated propeller aerodynamic characteristics and effects of propeller slipstream on turboprops were undertaken. The computational grid consisted of rotational subzone of propeller and stationary major-zone of aircraft, and walls criterion was used in the automatic hole-cutting procedure. Distance weight interpolation and tri-linear interpolation were developed to transfer information between the rotational and stationary subzones. The boundaries of overlapping grids were optimized for fixed axis rotation. The governing equations were solved by dual-time method and Lower Upper-Symmetric Gauss-Seidel method. The method and grid technique were verified by isolated propeller configuration and the computational results were in well agreement with the experimental data. The grid independence was studied to establish the numerical results. Finally, the flow around a turboprop case was simulated and the influence of propeller slipstream was presented by analyzing the surface pressure contours, profile pressure distribution, vorticity contours and profile streamline. It's indicated that the slipstream accelerates and rotates the free stream flow, changing the local angle of attack, enhancing the downwash effects, affecting the pressure distribution on wing and horizontal tail, as well as increasing the drag coefficient, pitching moment coefficient and the slope of lift coefficient.

Parallel algorithms for moving boundary problems by local remeshing

“…The grids move rigidly according the movements of bodies, requiring little processing on itself. If adopting unstructured grids (Gong et al , 2018; Horne and Mahesh, 2019; Karman and Sahasrabudhe, 2007; Löhner et al , 2001; Togashi et al , 2001; Xiao et al , 2016) instead of block structured grids, the flexibility of the overset grid approach can be enhanced even more. Nevertheless, the grid assembly step of this approach involves the time-consuming process of cutting holes, searching for donor cells and interpolating solutions.…”