CFD Predictions of Abrupt Wing Stall at Transition Speeds

摘要

The goal of the present study was to assess the ability of CFD to predictrnthe longitudinal characteristics of a military airplane baseline configuration withrnleading edge snag at different transonic Mach numbers. Steady State CFDrncalculations were performed based on the AVIC ARI-developed CFD codernUNSMB with Menter’s Shear Stress Transport turbulence model option. Grids withrndifferent fidelities were used during grid resolution study to determinate the gridrndensity that was required to accurately predicting the longitudinal characteristics.rnThe surface and flow field characteristics were examined to study the complexrnshockwave-boundary layer interactions and overall flow topology in the abruptrnwing stall region of interest. Comparisons with wind tunnel data were used tornvalidate the CFD results. Overall results have shown the flow to be very complex,rninvolving vortex flow, shock-boundary layer interactions, and massively separatedrnflow. In regions of local CLmax, increments at least as fine as 0.5º are needed tornappropriately capture the abrupt stall process.