On the Vertical Wind Velocity Distribution over the City and Roughness of the Buildings. ( The Experiment by Models I )

Abstract

The vertical distribution of mean wind velocity over the city was fitted to the logarithmic law as follows:
u=(u_∗/k) ln ((z-d)/z₀)
where u_∗, k, z₀ and d denote the friction velocity, Kármán’s const., roughness length and zero plane displacement, respectively.
On the relation between the roughness parameter (d and z₀) and the roughness on the ground carried out the experiment by models in the atmosphere. The models are the boxes made of the wood, 200 × 60 × 30 cm in size. This models were stood at an intervals of some distance at right angle to the wind direction and measured the wind velocity behind the box by small cup anemometers. From the results, d and z₀ are proportional to the height of the model but vary with D as are shown in Fig. 5 and Fig. 6.