Vortex Flow Control over a Delta Wing Using Leading-edge Rudder

Cai and Chng developed a vortex shedding theory for quasi-streamlined body in which the trailing edge is modified to form a base cavity. The flow control technology by using a leading-edge rudder to manipulate vortex shedding over a flat-plate delta wing is studied based on the previous research. Various rudders are installed at 12.5% chord line of the delta wing with a 48° sweep angle. The relative angle between rudders and delta wing is 42° . The experiments are performed in a low speed wind tunnel at angles of attack varying from 40° to 60° for the delta wing with a rudder and 0° to 70° for the delta wing alone. The test wind speed is 50m/s and the Reynolds number is 2.74×10 6 based on the root chord of the delta wing. Modal experiments are carried out for further study on low-frequency characteristic. The results contain dynamic force measured by a six-component internal strain-gage balance and first four modes measured by acceleration transducers. The wind tunnel experiments have confirmed that at high angles of attack, controlling rudders with specific wavy edge are able to improve drag oscillation characteristics and contribute to the aerodynamic efficiency.