The fluid forces on a single cylinder in cross flow are measured experimentally by strain gauges. The drag and lift coefficients of the cylinder are measured with momentum injection of various direction and magnitude. The results show that the drag coefficient of the cylinder is reduced with momentum injection. For higher Reynolds numbers, the magnitude of momentum injection must be increased to maintain the effectiveness of momentum injection. The influence of the drag coefficient is reduced when the angle of momentum injection is increased, and then the lift coefficient is varied obviously.

This research shows an experimental set-up of measuring forces acting on single cylinder in cross flow provided by a water tunnel. Water was also released at various directions from the cylinder surface to study the effect of momentum injection on cylinder forces. The fluid forces on the cylinder was measured by a strain gauge bonded on long-thin plat which is connected to the cylinder. The drag and lift coefficients of the cylinder were measured with momentum injection of various direction and magnitude. Experimental results show that the drag coefficient is effectively reduced with momentum injection at streamwise direction. Negative drag coefficient (propulsion) can be obtained if the magnitude of momentum inject is large enough. When the momentum injection has cross-stream component, lift force is obtained with its value depending on the magnitude of momentum injection. For higher Reynolds number, the magnitude of momentum injection has to be increased to maintain the effectiveness of momentum injection.