Zonal Detached-Eddy Simulation of an Airfoil in Poststall Condition

摘要

This paper presents a zonal detached-eddy simulation of a leading-edge stall airfoil in poststall conditions. Different detached-eddy-simulation-type methodologies are first evaluated and discussed and the paper presents in detail the results obtained with the mode 1 of the zonal detached-eddy simulation that is based on a prescribed switch between the Reynolds-averaged Navier-Stokes and the large-eddy simulation regions. The results obtained with the selected approach are presented and compared to detailed experimental results including unsteady pressure measurements and unsteady velocity flowfield measurements acquired using time-resolved particle image velocimetry and laser Doppler velocimetry. Important features of the flow are correctly captured by the computation and good agreements are observed with experiments on pressure distribution, separation location and aerodynamic forces. The unsteady properties of the calculation are also compared with unsteady measurements showing that the St = 0.2 frequency indicating that the vortex shedding is correctly predicted in the computation. Detailed analysis of the mixing-layer and the wake properties highlights some deficiency of the computations that are fully analyzed. Especially, the grid resolution in the early stages of the mixing layer appears to be of primary importance for the present application. The detailed comparisons of the zonal detached-eddy simulation result with the experimental data allow general requirements to be drawn for further improvements.