2019
Session ID : OS3-20
Conference information
Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 07, 2019 - November 08, 2019
Drag coefficient with holes
Details
Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 07, 2019 - November 08, 2019
The purpose of this study is to obtain drag coefficient of a circular plate with holes. Effects of holes on the drag coefficient are not understood sufficiently yet, however, there are some data about annular plates which show higher value than the circular plate. The drag coefficient shows larger value with larger the ratio of inner and outer diameters. It is strange from the definition of the pressure drag based on the difference between the high pressure in the front stagnation region and the low pressure in the rear separated region. Since there is no difference in pressure at the center of the annular plate because of hole, it is assumed to be a small drag. However, the fact is opposite. The following is a possibility. The test plate is falling in water according to the equation of motion. The change in speed of the plate is measured by a high-speed CCD camera. The experiments were carried out in a water tank. The plate was released from beneath the still water surface, and then, it fell down according to the equation of motion. The drag coefficient Cd of disk with holes is obtained.
