Reproduction of wind velocity history in a multiple fan wind tunnel

An actively controlled wind tunnel for simulating the atmospheric boundary layer is described. The air flows are generated by 99 frequency-controlled fans arranged in a 9 wide by 11 high matrix. Various fluctuating flows can be reproduced in this wind tunnel by altering the input data of the fans through computer control. In this paper the method used to reproduce the wind velocity history is described. Some experiments are carried out to investigate the basic performance of the wind tunnel. The simulations of velocity histories of the intermittent turbulent flow and fully developed turbulent flow are also carried out.