Two-degree-of-freedom bionic tail fin

Abstract

The invention provides a two-degree-of-freedom bionic tail fin comprising four parts, namely, a paddle frame groove, a paddle frame, blades and a transmission gear. Blade shafts of the blades are inserted in blade shaft holes in the paddle frame, the blades are connected with the paddle frame through a shutter type structure, and the blades can rotate around the shafts in the paddle frame. The paddle frame reciprocates in the paddle frame groove. The depth of the paddle frame groove is slightly smaller than the width of the upper border of the paddle frame. The upper border of the paddle frame is hidden in the paddle frame groove, and the paddle frame is prevented from being impacted by front currents, so that the water resistance received by the paddle frame structure during propelling is directly reduced. The tail fin can be specially implemented in single-paddle, double-paddle, multi-paddle-group manners and the like and has the advantages of efficient propelling, ship control, reduction of hydrodynamic noise, reduction of cavitation effects, ship hiding and the like.

Description

technical field [0001] The invention relates to a hull propulsion device, in particular to a two-degree-of-freedom bionic tail fin, which belongs to the technical field of paddle structures. Background technique [0002] At the present stage, among the propulsion methods adopted by ships of various sizes, no matter which propulsion method has certain disadvantages. Take the propeller propulsion method as an example: the propeller has a non-negligible axial area, and when the speed of the propeller is extremely high, its propulsion efficiency will decrease instead. The propellers are connected by shafting. During the rapid propulsion of the propeller, the hydrodynamic noise generated is also very large. The propeller also has a cavitation effect, that is, when the propeller speed reaches a certain value, bubbles overflow on the water-absorbing surface of the blade. The higher the speed of the propeller, the more serious the cavitation effect. The cavitation effect of the ...

AI Technical Summary

Problems solved by technology

The cavitation effect of the propeller will not only distort the water flow, make the blade idling, reduce the propulsion efficiency of the blade, but also may cause the appearance of strong shock waves and cause corrosion of the surface of the blade

For submarines, what is more serious is the generation of a large number of cavitation bubbles, causing the submarine to drag a trail and generate very large cavitation noise, which can easily reveal the position of the submarine.

Traditional wooden paddles do reciprocating motion. When reaching the limit position and returning in the opposite direction, the water will have as much resistance as the propulsion force, and the work done to overcome the restoring force is also very much, so wooden paddles can only be used for small personal boat

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