A Method for Generating Streamwise Velocity Disturbance in Low-Speed Wind Tunnel

Abstract

A method of wind tunnel testing is proposed for generating streamwise velocity disturbance in low Reynolds number flows. When a model moves along the free stream at a constant speed, the effective turbulence intensity for the translating model can be adjusted through the change in the relative velocity between the free stream and the model. The feasibility of the proposed method is experimentally verified in a wind tunnel with a linear motion mechanism installed in the test section. The experiment shows that the effective turbulence intensity for the translating model increases when the model moves along the free stream. Agreement in the lift coefficients between the tests with and without using the linear-motion mechanism confirms the feasibility of the proposed method. The experimental range available in turbulence intensity can be extended using the model streamwise translation. Moreover, a stepwise gust can be generated while the turbulence intensity remains almost constant when the model moves against the free stream.