Investigation of Flows Around a Rudimentary Landing Gear with Advanced Detached-Eddy-Simulation Approaches

摘要

Unsteady and massively separated flows past the rudimentary landing gear are investigated using delayed detached-eddy-simulation and improved delayed detached-eddy-simulation based on shear stress transport model. To eliminate the unfavorable influence of large numerical dissipation, a high order symmetric total variation diminishing scheme with adaptive dissipation approach is implemented. Three sets of grid, including the coarse, medium and locally refined grids are applied. It is observed that the grid density effect is weak on the mean flows, but significant on the instantaneous quantities. Both approaches present acceptable agreements with the available experiments. Due to its wall-modeled large-eddy-simulation mode, improved delayed detached-eddy-simulation can deliver slightly larger secondary separation and smaller horseshoe vortex on the aft wheels, predict the shear layer instability a little more upstream and resolve smaller instantaneous structures. There are strong interactions between vortices and sharp corners of the landing gear struts. Strongly periodical impingement of vortices also occurs from the fore wheel onto the rear one as well as onto the downstream part of the front wheel itself. These flow behaviors cause the high sound pressure level distribution and lead to surface noise.