An alternative approach to experimental simulation of wind characteristics in urban environments

The classical Counihan vortex generators for wind-tunnel simulations of the atmospheric boundary layer (ABL) flow were redesigned to experimentally simulate natural wind characteristics in urban environments. Three redesigned (truncated) vortex generators, a castellated barrier wall and a fetch of roughness elements were employed to reproduce a lower portion of the neutrally stratified ABL developing above an urban type terrain. A hot-wire anemometry system was used to measure mean velocity and velocity fluctuations. Investigated parameters were mean velocity, turbulence intensity, integral length scale of turbulence, and power spectral density of velocity fluctuations. Experimental results indicate that the truncated vortex generators developed for this study can be successfully employed in urban ABL part-depth wind-tunnel simulations, as they compare well with commonly applied empirical models and wind specifications for urban type terrain given in the ESDU 74031 data sheets.