Large Eddy Simulations of Wind-Driven Rain on Tall Building Facades

Abstract

Wind-driven rain (WDR) on building facades may lead to water penetration, cladding damage, structural cracking, etc., which affect the durability of the claddings. This study aims to develop a numerical approach to the evaluation of WDR on tall building envelopes based on large eddy simulations (LESs) and a Eulerian multiphase model. The present method utilizes the concept of the multiphase model to deal with rain and wind, and both wind and rain motions as well as their interactions are treated under the Euler frame, which can significantly reduce the complexity in evaluations of WDR and simplify boundary condition treatments. Besides these advantages, unsteady-state WDR information such as the transient catch ratio of WDR, the spatial and temporal distributions of rain intensity, etc., can be predicted by the LES. A validation study shows that the simulation results agree well with the available experimental data, verifying the accuracy of the simulation approach based on the Eulerian multiphase model and LES. Furthermore, a LES of WDR on the 508-m-high Taipei 101 Tower was performed to illustrate the application of the present method and to investigate WDR on a tall building. Both the transient and time-averaged WDR results are presented and discussed, demonstrating that the present approach can provide more information on WDR than the existing methods.