Ship model four-degree-of-freedom rotary arm test device and method

Abstract

A ship model four-freedom-degree rotating arm test device comprises a rotatable rotating arm and a measuring mechanism between the rotating arm and a ship model. The measuring mechanism comprises a middle base fixedly connected with a rotating arm trailer, heaving rods penetrate through the middle base and can vertically slide, a linear displacement sensor is installed on a base plate at the lower ends of the heaving rods, a counterweight is connected to the upper end of the base plate through a steel wire rope, a four-component force measuring sensor is connected to the lower end of the base plate and fixedly connected with a longitudinal swing base, the longitudinal swing base is rotationally provided with a longitudinal swing shaft connected with a rotational potentiometer, the longitudinal swing shaft is fixedly connected with a middle frame, and the middle frame is connected with a heeling angle adjusting mechanism. The invention further provides a test method, wherein according to the method, water power in the longitudinal direction, water power in the transverse direction, water power during rolling and water power during yawing are measured through rotating arm tests under five test working conditions, and then the water power derivative is worked out through corresponding maneuvering motion equations. According to the ship model four-freedom-degree rotating arm test device and the test method, trim angle measurement and heaving displacement measurement of the ship model and water power measurement of the ship model in four motion directions can be achieved, and the handling quality of a ship in the four motion directions can be forecasted.

Description

Technical field [0001] The present invention relates to the technical field of restrained ship model testing, in particular to a ship model swing arm test used to measure the hydrodynamic characteristics of the ship model when it moves in a circular motion, and in particular to a ship model swing arm test used to measure the ship model's heave displacement and trim attitude change during the rotation process. A test device for the hydrodynamic force of the ship model in four directions of motion (including longitudinal, lateral, roll, and bow) and the method of obtaining the hydrodynamic derivative through the test device. Background technique [0002] The restraint model test is currently the most widely used method to obtain the hydrodynamic derivative of a ship. It uses mechanical constraints to force the ship model to perform prescribed motions, such as linear motion and rotational motion. During the model test, the ship model is systematically changed. Motion parameters are ...

AI Technical Summary

Problems solved by technology

[0003] At present, most of the maneuverability predictions in still water at home and abroad use the two-degree-of-freedom or three-degree-of-freedom maneuvering equations, that is, the three hydrodynamic maneuvering equations of longitudinal force X, lateral force Y, and yaw moment N. However, due to the , ships with a high center of gravity (such as large container ships, ro-ro ships, etc.) have a large turning heel, and with the simulation technology research of maneuvering control under real sea conditions, this three-degree-of-freedom maneuvering motion equation cannot fully predict the high-speed ship and high-speed ship. The maneuverability of the center of gravity ship. Therefore, for the ship model jib test of the high-speed ship and the high center of gravity ship, in addition to the normal movement of the ship model with the yaw angle, it is also necessary for the ship model to be able to move freely in the vertical and pitch directions. At the same time, the variable heel hydrodynamic test can also be carried out. At present, there is no measuring device for the four-degree-of-freedom maneuverability cantilever test of the ship model, and due to the limited internal control of the ship model and the limited installation conditions of the cantilever pool, this is required. The arm test measuring device is not easy to be too large, which increases the design difficulty of the arm test measuring device

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