Experimental and numerical investigation of the length ratio and angle of attack effects on dynamic behavior of two plates perpendicular to the cylinder

In this study, experimental and analytical unsteady flow around a cylinder model with rotational degrees of freedom is discussed. Experimental studies at different speeds and angles of attack for two cylinder models with different length ratios have been done. Meanwhile the analyses of numerical technique known as vortex panel method have been used. Analytical and experimental results show that the rotational and vibrational motion and a combination of these behaviors occur. These types of behaviors depend on ratio of length plates to cylinder radius, primary object angle of attack and free stream velocity. At different speeds and at all angles of attack for a length of less than 1, the model has vibrational Motion around a specific angle. This angle for cylinder with two plates is 90 degrees. Generally, the model tends to vibrational motion at low angles of attack with increasing length ratio and free stream velocity occurs and by increasing the Primary angle of attack is the desire to vibration motion around a specific angle. Also, in free stream velocity 10(□(m/sec)) and Higher, for length ratio 4, the model had a steady rotational motion. In addition, angular velocity models and Strouhal number on rotational motion is calculated. The results show that Strouhal Number is a fixed amount, by increasing the Reynolds Number.