Simulation of prescribed boundary flow conditions in a multiple controlled fan wind tunnel

The development of a method to simulate desired approach flow characteristics in a multiple controlled fan wind tunnel (MCFWT) is described. A MCFWT uses flow control techniques to impart the desired turbulence characteristics in a wind tunnel in lieu using a roughness grid upwind of the test section to generate a boundary layer. In contrast to other MCWFT techniques, the proposed approach (a) relies on the direct simulation of scaled wind speed and direction records collected during field experiments and (b) implements a closed-loop proportional-integral-derivative controller to modulate the wind speed and control the longitudinal turbulence characteristics. A case study is presented using a 1:10 scale model of the Institute for Business & Home Safety Research Center Full-Scale Test Facility. Simulation of marine, open and suburban approach boundary layer flow yields good agreement between the model and measured values, including mean velocity and turbulence intensity profiles, integral length scales and power spectra. Control of longitudinal and lateral fluctuations is considered herein. Good agreement between the target and measured vertical turbulence intensity profiles was also achieved after the longitudinal and lateral turbulence profiles were obtained through the proposed approach.