CFD modeling of the wind-driven rain distribution over a small hill and valley and comparison with full-scale measurements

Full-scale measurements have shown that variations in wind-driven rainfall (WDR) distribution over small-scale topographic features such as small hills and valleys can be quite large. Therefore, these variations should be taken into account in e.g. catchment hydrology, runoff and erosion studies and in the design of rainfall monitoring networks. Full-scale measurements however are expensive and time-consuming. A few researchers have attempted numerical modeling but model validation is rather scarce. This paper presents 2D Computational Fluid Dynamics simulations to determine the wind-driven rainfall (WDR) distribution over a small isolated hill and in a valley. Validation is performed by comparing the numerical results with fullscale measurements. It is shown that the CFD simulations can provide a good indication of the WDR distribution over these types of small-scale topography.