Effects of Side Walls on Pipe Inlet Flow(Drag Reduction by Separated Flow Control Using Ring Shaped Small Obstacle)

Journal of Fluid Science and Technology

Koichi TSUJIMOTO¹  Toshihiko SHAKOUCHI¹  Toshitake ANDO¹  Hiroyuki YAMAMOTO¹ 

[1] Graduate School of Engineering, Mie University;

关键词: pipe inlet flow;    flow separation;    flow control;    drag reduction;    lda;   

DOI  :  10.1299/jfst.4.468

来源: DOAJ

【 摘 要 】

The flow from a wide space into a pipe has a large annular separated vortex region just after the inlet corner. This vortex region produces large flow resistance, or drag, in this kind of flow. To reduce the drag, a means to control flow in order to suppress the vortex region is needed. In this study, a simple method to reduce the drag of the pipe inlet flow by mounting a small ring-shaped obstacle instead of a bell-mouth has been proposed and examined. The effects of the side-walls and their offset distance on drag reduction were also examined. The small offset distance corresponds to the case in which the pipe inlet is placed near the bottom or corner of the tank. The distributions of pressure and velocity components in the axial direction at several cross-sections were measured, and a visualized flow pattern of the water flow just after the pipe inlet was examined. The effects of the small ring-shaped obstacle on drag reduction were also examined. It was clarified that the inlet loss (drag) coefficient was reduced by a maximum of about 90 percent by mounting the ring-shaped obstacle.

【 授权许可】

Unknown