While airframe noise can be reduced by using porous surface materials, the aerodynamic behavior is often adversely affected. The project develops a model for predicting the effects of porous surfaces on turbulent boundary layers by computation of the volume and Reynolds averaged Navier-Stokes equations. The current implementation of a Reynolds stress equation model of turbulence will be extended to account for non-isotropic materials and materials with gradients in the pore structure. The model will be calibrated using inverse Bayesian updates. Model validation will be performed for airfoil flows with and without Coanda-flaps.