Flow characteristics around a rotating grooved circular cylinder with grooved of different depths
- 193 Downloads
The present paper describes the flow characteristics around a rotating grooved circular cylinder with grooves of different depths. The surface structure of a circular cylinder was varied by changing the depths of 32 arc grooves on the surface. The surface pressure on the cylinder is measured for theRe range of from 0.4×105 to 1.8×105 and for rotations of from 0 to 4500 rpm. The drag coefficient of a grooved cylinder increases as the spin rate ratio α (= rotational speed of the cylinder surface/uniform velocity) increases forRe>1.0×105. As the groove depth increases, the drag coefficient of a grooved cylinder is independent from the spin rate ratio α. The direction of the lift force of a smooth cylinder is opposite to the Magnus force forRe>1.0×105. However, the direction of the lift force of a grooved cylinder is the same as that of the Magnus force for allRe>1.0×105. As the groove depth increases, the increase in the slope of the lift coefficient becomes small. These phenomena are related to the positions of the flow separation points, which are clarified from the pressure distribution and flow visualization by the spark tracing method. In addition, in the present study, the flow around a rotating grooved cylinder is clarified by flow visualization.
KeywordsRotating cylinder Spark tracing method Fluid force Pressure distribution
Unable to display preview. Download preview PDF.
- Aoki, K., Shimada, T. and Takayama, S., Flow Characteristics around Circular Cylinder with Arc Grooves, Proc 7th Asian Symposium on Visualization, Singapore, (2003).Google Scholar
- Gushchin, V. A., Kostomarov, A. V. and Matyushin, P. V., 3D Visualization of the Separated Fluid Flows, Journal of Visualization, 7-2 (2004), 143–150.Google Scholar
- Swanson, W. M., The Magnus Effect: A Summary of Investigations to Date, Transactions of ASME, 83 (1961), 461–470.Google Scholar
- Takayama, S., and Aoki, K., Pressure Response Characteristics of a Measurement System for a Rotating Cylinder, Proc the school of engineering of Tokai University. 43-1 (2003), 73–77 (in Japanese).Google Scholar