A spire array for generating thick turbulent shear layers for natural wind simulation in wind tunnels

Investigates use of an array of spires, located at the entrance to the working section of a conventional wind tunnel, as a means of generating thick shear layers with properties similar to those of the neutrally-stable atmospheric wind. Compares data obtained in the shear layers created by sucharrays of spires with some available atmospheric data. Modifications to thespire design and a range of spire sizes have been tested and the resulting shear layer properties compared. Sufficient information and experience has been obtained to apply the technique to tunnel tests of urban structures in which shear layers of predetermined depth and power low velocity distribution are required.