特殊な間隙を有する長方形板の空力特性について

概要

論文の詳細を見る
Flat plate standing perpendicularly in the wind receives large drag because of the flow separation from the plate edge and the following large eddy region. This eddy region, called wake, is affected by the boundary condition around the plate, and then affects the drag force. In this study, the aerodynamic characteristics of the rectangular flat plate with a special opening were experimentally investigated at the various boundary conditions. The model plate was manufactured as a sliding shutter by the company O and the company K. The opening ratio of the plate is about 18 percent. According to the experiment, the drag coefficient of the specimen did not vary from the same plate but without the opening. Drag coefficient in the case of no boundary, specimen in the uniform flow, is 1.19, which is somewhat higher than the value 1.12 of the thin rectangular flat plate. The difference is seemed to be caused by the thickness and the edge shape of the plate. In the worst boundary condition, the flat plate placed on the center of the large wall, the drag coefficient reachs to 1.59, which is 34 percent larger than the value in the case of no boundary. However, if a kind of wind shutter is placed behind the model, the drag force acting to the model becomes almost negligible. Pressure oscillating phenomena are also researched, and it is tried to explain the frequency by the Kármán vortices and Helmholts resonance.
琉球大学工学部の論文