Wind-Driven Rain

Wind-Driven Rain

In areas around the world where downpours or sudden rain events are common, it is essential to understand the impact this can have on roofing and pedestrianised areas.

WINDTECH conducts CFD or wind tunnel testing combined with CFD to accurately quantify the amount of rain that impacts each area of a development. Statistical analysis of meteorological data is combined with results from testing in WINDTECH’s boundary layer wind tunnel facilities. The results from this testing can then be integrated into the CFD software as boundary conditions.

Results are presented in a report, identifying areas where rain fall accumulates due to wind flow and rain fall intensity in the form of wind driven rain contour plots.

Similar studies can be carried out for wind driven snow or wind driven sand.

Case Study: Central Embassy, Bangkok , Thailand

A wind driven rain analysis was undertaken for the Central Embassy development in Bangkok, Thailand using a hybrid wind tunnel and CFD approach to quantify the amount of rain that impacts the roof and surrounding areas of the development.

Wind driven rain “catch ratio” contours were presented for each of the outdoor/semi-indoor pedestrian regions, as well as wetted surface contours for the ground level. The modelling included the rain properties for the Bangkok region as well as the wind flow throughout the development for four predominant wind directions.

Central Embassy, Bangkok, Thailand – 3D CFD wetted surfaces contour throughout the development and its neighboring regions for an annual rain-fall event.