Wind-driven rain is defined as the quantity of rain that passes through a plane with
defined orientation in the atmosphere. It is well known that rain water (wind-driven rain)
causes more than 90% critical damage to buildings. As the most important boundary
condition, wind-driven rain has significant effect on the accuracy of hygrothermal building
component simulation. The existing wind-driven rain estimation approaches have limits.
They are either: 1) over simplified and cannot capture comprehensive essential effects,
or 2) too complicate to perform. The aim of the present study is to develop a new winddriven
rain model, WDR-Pdr model. Field measurement, CFD (Computational Fluid
Dynamics) simulation and statistical analysis are used in this study. By using WDR-Pdr
model wind driven rain on building façades in street canyon can be estimated. During
the study of the wind-driven rain model, more influencing factors such as the density
of buildings and the arrangements of the surrounding buildings are taken into account.
Based on observations and statistical analysis, the correlation between wind pressure
and wind-driven rain was studied out. As a result, a new parameter, wind pressure
Pdr, is used in this new model which is in conjunction with M.Grosso's wind pressure
model. As a parametric model, WDR-Pdr model is convenient to use and it economize
the complicated processes of CFD simulation and data processing.