Features of the flow over a rotating circular cylinder at different spin ratios and Reynolds numbers: Experimental and numerical study

.In this study, the characteristics of the flow in a rotating circular cylinder are investigated experimentally and numerically. The hot-wire anemometry is used to measure the mean velocity and turbulent intensity of the flow, also the k- SST model is used to extract the numerical results. The diameter of the cylinder is considered to be 20mm. The effect of Reynolds number ( Re ) in the range of (5900 Re 11800) and the spin ratio () in the range of (00.525) on the characteristics of the flow wake such as time-averaged velocity, turbulence intensity, higher-order central moments of the hot-wire velocity signals (i.e. skewness factor), Strouhal number, drag coefficient and flow pattern have been investigated. According to the experimental results, the cylinder rotation has led to change in the mean and fluctuation velocity profiles and the velocity reduction region has become smaller by increasing the Reynolds number. Furthermore, the symmetry of the flow is broken as the rotation ratio increases. Also, by increasing the rotation ratio, the positions of the stagnation and separation points are changed. It is found that with increasing the rotation ratio, the drag coefficient and the velocity reduction parameters are decreased.