Wall interference during testing a blutled body in transonic flow

The paper presents the results of numerical simulation of a transonic flow around a blunt body at zero angle of attack in the test section with porous walls of T-128 wind tunnel (Russia, TsAGI). The calculations were performed using the EWT-128 TsAGI software package, which uses Darcy-type boundary conditions on the walls of the test section, the porosity coefficient of which depends on the direction of gas flow through the perforated surface. A comparison is made of the calculated and experimental drag coefficients of the model, as well as distributions of the isentropic Mach number on the model and on the perforated walls of the test section of the WT. A method is proposed for determining the correction to the Mach number of the oncoming flow to eliminate the wall interference of the test section in an aerodynamic experiment. The drag coefficients obtained as a result of calculations under wind tunnel conditions are corrected for the influence of the flow boundaries and compared with the free flow data. The calculated corrections are used to correct the experimental data.