Evaluation of flow characteristics in the NUS-HDB Wind Tunnel

A new low-speed boundary-layer wind tunnel has been designed and constructed at the National University of Singapore. A series of flow-characteristic evaluations were performed in this wind tunnel to determine the uniformity of flow and to verify its adequacy to simulate the atmospheric boundary layer for wind load studies on structures. This paper presents the results of mean velocity measurements in the empty tunnel using a Pitot-static tube, and measurements of mean and fluctuating velocities and flow characteristics in a simulated boundary layer using a hot-wire anemometer. The measurements of mean velocity in the empty-tunnel condition showed a two-dimensional uniform velocity distribution and low turbulence intensities. The simulation of natural wind in urban terrain was carried out using the Counihan simulation method that consists of a castellated barrier wall, quarter-elliptic wedge spires and roughness elements. The simulated results were found to compare well with the atmospheric data for urban terrain at a scale of 1:375.