Research On Mechanical Properties And Structural Optimization Of The Otter Board

In order to meet the development needs of fishery modernization,the improvement of fishing gear is an indispensable part of it,and the otter board is the main attachment to provide the horizontal tension of trawl nets.The use of double-slotted curved otter board helps to increase the lift coefficient and lift-to-drag ratio of the otter board,and the otter board opening is advantageous for reducing the back vortex of the otter board,increasing the hydrodynamic performance of the otter board,and improving the operational stability of the otter board.In order to study the hydrodynamic performance of the small trawler otter boards,This paper mainly uses numerical simulation to control the single change of the parameters such as the angle of attack,speed,slit size,aspect ratio,and de-operation level of the double-slotted rectangular curved otter board under certain parameters.To study the influence of its changes on the hydrodynamic performance of trawl nets;Control the single change of the parameters of the vertical V-shaped curved otter board,such as the angle of attack,aspect ratio,folding angle and deflection angle,and study the influence of the change on the hydrodynamic performance of the otter board.The numerical results show that the lift coefficient and lift-drag ratio of the otter board increase first and then decrease with the increase of the angle of attack.The best lift-to-drag ratio occurs when the angle of attack is about 10°;The performance has no significant effect;the lift coefficient generally increases with the increase of the slit size.When the slit size is larger than 50 mm,the lift coefficient does not change significantly,and the lift-to-drag ratio increases first and then decreases with the increase of the slit size;When the lift coefficient reaches the maximum,the corresponding angle of the otter board with different aspect ratio decreases with the increase of the aspect ratio.At the same time,the peak of the lift coefficient increases first and then decreases with the increase of the aspect ratio.When the aspect ratio is about 0.6,the peak of the lift coefficient reaches the maximum;The hydrodynamic performance of mid-level operations is significantly better than that of bottom-level operations.The lift-to-drag ratio of the vertical V-shaped curved mesh plate appears at an angle of attack of about 13 °;the lift coefficient and lift-to-drag ratio increase with the increase of the aspect ratio;the lift-to-drag ratio increases first and then increases with the increase of the bending angle The trend of the decrease is that when the folding angle is about 6 °,the lift-to-drag ratio is the largest;the lift coefficient and the lift-to-drag ratio increase first and then decrease with the increase of the deflection angle,and the drag coefficient is basically unchanged;Steel and drag steel are connected,and the stress concentration becomes more obvious as the angle of attack increases.The results of this study can provide a more reliable reference for the structural optimization design of the same type of small trawler otter board in the future.