Numerical assessment of turbulence effect on the evaluation of wind-driven rain specific catch ratio

The present study aims to evaluate the importance of wind turbulence when performing droplet trajectory numerical simulations. Turbulence effect on Wind-Driven Rain is studied by calculating the specific catch ratio of 1 mm droplets for an isolated low-rise building windward surface under a 5 m/s normal wind. An Eulerian Second Moment Closure and a Lagrangian one-way coupling models are used to calculate the airflow field and the droplet trajectories respectively. Results show that turbulence has a negligible effect considering the whole windward wall but can substantially modify the value of the specific catch ratio in the case of Wind-Driven Rain gauges.