Effect of bevel angle of three-layer parallel plate on hydrodynamic performances of otter-board

The effect of bevel angle of three-layer parallel plate of otter-board on hydrodynamic performances is investigated by model wind tunnel test. Four otter-board models are designed with four different bevel angles (8°, 10°, 12° and 14°) , and tested under the wind speed 28 m / s in wind tunnel. Model experiment is conducted to obtain the drag coefficients Cx, the lift coefficient Cy, the pitch moment coefficient Cm, the center of pressure coefficient Cp and calculated the lift-drag ratio Cy/Cx. The result shows that the maximum lift coefficient and the maximum lift-drag ratio of the otter-board model with a bevel angle 12 degree is higher, there is 2.598(a=65°) and 2.607(a=37.5°); For comparison in stability of otter-board, the stability of the otter-board model with the bevel angle 8 degree is better by the comparative analysis of Cm and Cp, the absolute value of Cm is 0.174 and the minimum variation coefficient of Cp is 4.37%. The results can offer reference for the structural optimization design of trawl otter-board.