Numerical ABL wind tunnel simulations with direct modeling of roughness elements through immersed boundary condition method

Abstract

Reproduction of atmospheric boundary layer wind tunnel experiments by numerical simulation is achieved in this work by directly modeling, with immersed boundary method, the geometrical elements placed in the wind tunnel’s floor to induce the desired characteristics to the boundary layer. The numerical model is implemented on the basis of the open-source flow solver caffa3d.MBRi, which uses a finite volume method over block structured grids, coupled with various LES approaches for turbulence modeling and parallelization through domain decomposition with MPI. The Immersed boundary method approach followed the work of Liao et al. (Simulating flows with moving rigid boundary using immersed-boundary method. Comput. Fluids 39, 152-167, 2010). Numerical simulation results are compared to wind tunnel measurements for the mean velocity profiles, rms profiles, and spectrums, providing good overall agreement. We conclude that the Immersed Boundary Condition method is a promising approach to numerically reproduce ABL Boundary Layer development methods used in physical modeling.