Roughness estimation for wind-load simulation experiments

Wind Engineers engaged in wind tunnel simulation experiments for the assessment of wind loads on low-rise structures have to cope with the problem of how to reproduce the pertinent flow parameters characterizing the atmospheric surface layer. Seldom are field observations available, and for the majority of the cases the simulation is therefore not based directly on observed flow quantities at the building site. Instead the Wind Engineer must assess visually the roughness of the terrain at the building site and match it with a particular class from an existing terrain classification. The latter provides then a measure of the roughness in the form of the roughness length that can be used to provide an estimate of the turbulence parameters of the flow to be reproduced in the laboratory using basic principles. The proposed method to obtain these parameters can be easily adapted for a user-friendly electronic evaluation with the prescribed roughness length.