抄録
Our aim is to optimize the aerodynamic shape of airships, which cruise at high Reynolds number. A cryogenic wind tunnel is used to achieve the desired flow. In the present paper we discuss the drag coefficient for airship models incorporating suction slots, for the purpose of boundary layer control. The pressure distributions on the models are measured over a wide range of Reynolds number for various suction discharges. By integrating the pressure distributions, it was found that the profile drag could be reduced using boundary layer control as low as the theoretical limit. Furthermore, the flow patterns around the models can be classified into four categories. The relationship between suction and surface velocity was also examined, which is critical in understanding drag reduction.
