Drag force and pressure distribution on cylindrical protuberances immersed in a turbulent channel flow

An experimental investigation of the drag and pressure distribution on several circular cylinders of different length-to-diameter ratios immersed in a turbulent channel flow has been conducted. Also, much of the published literature concerning velocity gradient flow about circular cylinders was reviewed. It was found that the flow field differed from that obtained on an infinite-length cylinder immersed in a uniform flow mainly because the stagnation-pressure gradient produced a secondary flow toward the low-pressure base region. In addition, deflection of the streamlines over the free end of the cylinder induced an additional secondary flow up the leading edge toward the free end. The point on the leading edge from which the secondary flows originated (the maximum pressure region) moved up the cylinder with increasing length-to-diameter ratio. A secondary flow was also formed at the trailing edge of the cylinder. Its direction was from the base toward the free end. The pressure distributions around the cylinders were similar in shape to those obtained by other investigators over infinite-length cylinders at much lower Reynolds numbers.