Characterization & Improvement of Low Speed Wind Tunnel

Universiti Teknologi PETRONAS (UTP) is having three low speed wind tunnels for researches and demonstration. Wind Tunnel II is designed and fabricated to provide flow visualization applications and 1/10 model studies. Preliminary tests have shown high unacceptable turbulence intensity in the test section. The wind tunnel is re-designed with many added improvements and modifications. This paper describes the design, fabrication, characterization, and validation tests of the wind tunnel. The validation criteria involve CFD simulation and experimental tests. The computational simulation is carried out by modeling with GAMBIT, FLUENT and ANSYS software. CFD simulation has proved its superiority as a powerful tool for design and analysis with considerably reduced time and cost. The experimental tests involve flow visualization and measurements by hot-wire anemometry. In the first stage, the turbulence intensity level, for the entire velocity range is measured to be around 10% near the walls reduced to around 3% at the central portion of the test section. The modifications of the inlet nozzle, the test section and the fan section have reduced the turbulence intensity level to be less than 1% in the test section. Good agreement between the test results and the simulation results are obtained after the modifications.
Keywords: Turbulence, Wind Tunnel, CFD Simulation, Honeycomb.