Influence of main-panel angle on the hydrodynamic performance of a single-slotted cambered otter-board

摘要

The effect of the main-panel angle of a single-slotted cambered otter-board was investigated using engineering models in a wind tunnel.Three different angles (0°,6°,and 12°) were evaluated at a wind speed of 28 m/s.Parameters measured included:drag coefficient Cx,lift coefficient Cy,pitch moment coefficient Cm,center of pressure coefficient Cp,and the lift-drag ratio Cy/Cx,over a range of angle of attack (0°-70°).These coefficients were used in analyzing the differences in the performance among the three otter-board models.Results showed that the maximum lift coefficient Cy of the otter-board model with a main-panel angle of 0° was highest (1.875 at α =25°).However,when the angle of attack was smaller (0 ＜ α ＜ 22.5°),the lift coefficient of the otter-board increased as the angle of the main-panel increased.The maximum Cy/Cx of the otter-board with a main-panel angle of 12° was highest (7.417 at α =2,5°),and the lift-drag ratio increased when the angle of the main-panel increased within the angle of attack at small angles (0 ＜ α ＜ 12.5°).A comparative analysis of Cm and Cp showed that the stability of the otter-board with a main-panel angle of 0° is better than those of the other models.Therefore,the comparative analysis of Cm and Cp,shows that a larger angle of the main-panel can reduce the stability of single-slotted otter-board.The findings of this study offer useful reference data for the structural optimization of otter-boards for trawling.