Design of Low Reynolds Number Airfoils with Trips

A design philosophy for low Reynolds number airfoils that judiciously combines the tailoring of the airfoil pressure distribution using a transition ramp with the use of boundary-layer trips is presented. Three airfoils with systematic changes to the shape of the transition ramp have been designed to study the effect of trips on the airfoil performance. The airfoils were wind-tunnel tested with various trip locations and at Reynolds numbers of 100,000 a nd 300,000 to assess the effectiveness of the design philosophy. The results show that the design philosophy was successfully used in integrating a boundary-layer trip from the outset in the airfoil design process. For the Reynolds numbers and the range of airfoil shapes considered, however, airfoils designed with trips do not hold any clear advantage over airfoils designed for good performance in the clean condition.