Investigation Of Wall Interference Correction In Transonic Wind Tunnel With Porous Wall

To reduce the air shock wave interference,blocking effect,wall lift effect and the wall boundary layer growth,porous wall was used to transonic wind tunnel.However,the flow of tunnel wall go into more complex because of it bring considerable difficulty into the wall interference correction.In order to correct the wall interference for the transonic wind tunnel,the CFD method was used.The wall surface flow near the hole based on FL-3 transonic wind tunnel test section model is carefully studied.And the influence to the flow near the hole by the pressure difference on both sides,free flow Maher number,the boundary layer thickness,hole diameter ratio and the hole inclination angle is deeply discussed in this paper.Summed up the porous wall flow characteristics of transonic wind tunnel,combining with the flow theory to establish the porous wall flow model.Finally instead of porous wall boundary conditions by the model which has been established,and was used in wall interference correction of transonic wind tunnel.NACA0012 airfoil is used to two-dimensional interference correction of porous wall.The pressure coefficient on airfoil surface changed obviously due to the difference of porous wall.The porous wall boundary condition has a good performance.This method is applied to wall interference correction of DLR-F4 wing body in 3D,The correction is close to that of wall pressure information correction method.The experimental values which has been corrected show closer to the true value.This method greatly simplifies the complex flow near the porous wall,additional wall pressure measurements wasn't needed during the experimental process.This reduce the cost and improve the accuracy of wall interference correction greatly.