عنوان مقاله [English]
One of the main applications of wind tunnels is to produce a controllable and steady flow with minimum turbulence intensity in its working section. Instabilities and separation of flow in the inlet and outlet of the contraction are the main factors in increasing turbulence intensity in the test section. Forced transition using a trip strip is a suitable method for turbulence reduction in wind tunnels. In this investigation, subsonic wind tunnel experiments were conducted to study the effect of a tripped boundary layer on pressure distribution in the contraction region of the tunnel. Measurements were performed by installing a trip strip at four different positions in the convex portion of the contraction. The results show that installation of the trip strips has a significant effect on both turbulence and pressure distribution. The reduction in free stream turbulence and wall static pressure distribution was significantly affected with the location of the trip strip. For example, at X/L=0.79, the unfavorable pressure gradient is weaker and the instabilities are less than at other positions. Consequently, for this position, the lowest amount of turbulence intensity in the test section is obtained.