Simplified elements for wind-tunnel measurements with type-III-terrain atmospheric boundary layer

Abstract

In this work, the results of simulating the ABL over a type III suburban terrain in the industrial wind tunnel of the Department of Mechanical Engineering of the Vrije Universiteit Brussel (VUB) are presented. Two different Roughness Barrier Mixing Device (RBMD) methods for simulating the ABL have been used (firstly, the well-known combination of Counihan quarter ellipses and roughness elements, and secondly, a new configuration based on truncated Irwin spires and roughness elements). Counihan quarter ellipses are generally considered as the optimal method for ABL simulation. However, its construction is quite complex. Therefore, an alternative setup, using truncated Irwin spires, was experimentally tested. The results of these two simulated ABLs were compared with international standard applicable for type III suburban terrain. Results showed good agreement between standards and experimental results showing that both techniques give a good representation of the ABL. Finally, the proposed truncated Irwin spires method/configuration is confirmed as a proper way to carry out ABL wind-tunnel simulations, as the results are practically the same as the ones obtained with the well-established Counihan method to simulate ABL in wind tunnels.