Experimental investigation of unsteady flow over a cylinder model with three plates perpendicular to it

In this research, the experimental investigation of unsteady flow around a cylinder model with three plates perpendicular to it has been discussed. This study has been done at different speeds, primary model angle of attacks and length ratios. The results show that the model has steady and unsteady oscillation and rotational motions. These types of behaviors depend on the plate’s length ratio, primary object angle of attack, and free stream velocity. The model has damping motion around an angle of 60 degree, at low speed and length ratio. The greatest oscillational or rotational flow has appeared at initial angle of attack of 0 degree. In low length ratio, the regime of motion is oscillations that it changed to rotational motion when the length ratio and free stream velocity increase. The variation of angular velocity at length ratio of 1 and 4, with respect to time, are accompanied with reduction of vibrations range per motion. Also, over time, the vibrational velocity of the model is reduced. In addition, the results show that by increasing the Reynolds Number, Strouhal number becomes constant.