Active control of turbulence for an atmospheric boundary layer model in a wind tunnel

Many types of meteorological and boundary layer wind tunnels have been used for a long time to simulate the atmospheric effects on large structures and the transport of air pollutants. In addition, a few actively controlled wind tunnels have been proposed to obtain more realistic effects on structures. New types of multiple-fan wind tunnels have been developed in our laboratory. To produce the required wind turbulence in the tunnels, fans and oscillating airfoils were controlled independently by a computer. Statistical parameters, such as mean wind velocity, turbulence intensity, turbulence scale and power spectral density profiles in a boundary layer, were satisfactorily reproduced in the tunnel. In addition to these parameters, a Reynolds stress profile was achieved and corresponding coherent motions were observed in the boundary-layer flow. (C) 1999 Elsevier Science Ltd. All rights reserved.