Effects of turbulence intensity and integral length scale on an asymmetric airfoil at low Reynolds numbers.

摘要

In the thesis, the performance of an asymmetric, high-lift S1223 airfoil has been investigated at Reynolds numbers 55,000, 75,000, and 100,000. The airfoil was tested in a quasi-isotropic turbulent flow generated using orificed perforated plates. The independent effects of the turbulence intensity were examined at a constant integral length scale. The stall of the airfoil is delayed by increasing the turbulence intensity. The wake of the airfoil becomes narrower and the strength of the shedding vortices was reduced, which indicates a suppression of the boundary layer of the airfoil. The independent roles of integral length scale were examined at turbulence intensity of 4.1% and 9.5%. At Tu=4.1% with increasing the integral length scale, the stall of the airfoil is delayed, and wider wakes have been observed at the stall region. At Tu=9.5%, the effects of turbulence scale become subtle.