TURBULENCE STATISTICS IN THE DEVELOPING URBAN BOUNDARY-LAYER

摘要

Since most scale-model studies of obstacle arrays are fairly limited in fetch, it can be expected that the internal boundary layer will likely be in a state of dis-equilibrium, with non-dimensional shear S > 1. If one measures the friction velocity using the slope method, the value of u* determined will be larger than the value obtained from Reynolds stress correlation, by as much as 50-70%. Only in very long fetch obstacle arrays (x/H > 200) does the non-dimensional shear approach unity so that u* can be accurately determined from a mean velocity profile.