The Influence of Windtunnel Sidewalls on Steady Transonic Flows

In this paper the role of windtunnel sidewalls is investigated by numerical simulation for a closed windtunnel test section. The boundary layer development starts 20 wing model chord lengths upstream of the model. The model is a 3D model with supercritical airfoil typical for a modern civil aircraft wing called aerostabil wing. For this wing it is shown that results applying sidewall boundary layer simulation yield an improved agreement with experimental results. Simulations are performed by solution of the RANS (Reynolds Averaged Navier-Stokes) equations together with the 1-eq. turbulence model of Spalart-Almaras. Results show clearly the effect of sidewall boundary layers by comparing with corresponding simulations applying Euler boundary conditions at the sidewalls. In several cases local flow separation appears in the corners between sidewall and model surface.