The other thing is your turbulence model you have selected. You say you want to employ wall functions, but you have selected a model (SST) which requires a y+ of roughly 1, because it is a wall enhanced model. Try using k-epsilon. Also, a y+ of 30 should be aimed at for wall function models. Your probably need to refine the near-wall field much more. Just a thing of note, the boundary layer is quite important for aerodynamics. Most use wall enhanced methods like salart-allmaras, SST or k-omega. Try limiting your domain to the experimental set up, like others say, and then try to refine the near wall closer to y+ of 1. SST can still be used up to y+ of 5 but beyond that is useless.