Experimental Investigation On Vortex Induced Vibrations Of Bio-Cylinders Based On A Harbor Seal Vibrissa

In this study,an inhomogeneous surface cylinder based on seaport sealing contacts was studied to reduce suppress vortex shedding.The three sealed whisker-based bionic cylinder models(ie,Models #1,#2,and #3)have different undulating wa velengths.These tests took place in the wind tunnel of the Joint Laboratory of Wind Tunnels and Waves at Harbin Institute of Technology in China.According to the hydrodynamic diameter(Dh)and the inlet flow velocity,the wind tunnel experiment was performed under Reynolds number Re?50000.These tests took place in the wind tunnel of the Joint Laboratory of Wind Tunnels and Waves at Harbin Institute of Technology in China.The control effects of the amplitude of acceleration and flow structures during t he period of VIV around the cylinders on the biological surface were studied and compared with the amplitude of acceleration and flow structures of the baseline cylinders.In addition to measuring amplitude of acceleration using an acceleration transducer,a Digital Particle Image Velocimetry(PIV)system was used to quantify the flow-to-fluid structure to evaluate the validity of the bio surface cylindrical model.The results show that the bionic non-uniform surface distribution can suppress the vortex induced vibration(VIV)in some situation.When the VIV excited,the amplitude of acceleration of the bionic cylinder model #1 is higher than that of the baseline circular cylinder model at the 0° wind attack angle.While the amplitude of acceleration decreased when the wind attack angle is 45°.The PIV system was used to measure the flow structure of the test model #1 at 0° wind attack angle.And it was found that in the wake behind the bio surface cylinder,the TKE level at the attack angle of 0 degrees is significantly reduced,indicating that Lower turbulence levels near the wake.