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Asymmetric underwater cavitation edge feature and motion parameter extraction method

A technology of water entry cavitation and edge features, applied in image data processing, instruments, calculations, etc., can solve problems such as propeller damage, propeller resistance limitation, erosion, etc., and achieve the effect of saving time and energy

Pending Publication Date: 2021-02-26
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Cavitation around the hull propellers can cause severe erosion, damage to the propellers and limited propeller drag

Method used

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  • Asymmetric underwater cavitation edge feature and motion parameter extraction method
  • Asymmetric underwater cavitation edge feature and motion parameter extraction method
  • Asymmetric underwater cavitation edge feature and motion parameter extraction method

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Embodiment Construction

[0028] In order to make the technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the drawings in the embodiments of the present invention:

[0029] In order to realize the specific implementation process of this method, an image system for the water-entry cavitation experiment is built, as shown in Figure 9 As shown, wherein the high-speed camera 5 is placed at an appropriate distance directly in front of the experimental water tank 1, and one end is connected with the computer 4; Experimental image processing of vacuoles. The following examples illustrate the present invention's water-entry cavity edge features and the specific method of motion parameter extraction and analysis:

[0030] The experimental images of four different horizontal initial velocities of the ball entering the water are selected for analysis and research...

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Abstract

The invention discloses an asymmetric underwater cavitation edge feature and motion parameter extraction method. The method comprises the steps of performing gray scale transformation and histogram equalization on an underwater cavitation image to obtain an enhanced image; carrying out edge detection on the enhanced image by adopting a Canny edge detection operator; screening the edge coordinatesof the underwater cavitation bubbles of the enhanced image, and unifying the coordinate values of the edge coordinates under different working conditions; analyzing batch extraction and data of edge features and motion parameters of the underwater cavitation bubbles, and acquiring the change process of the horizontal displacement of the lowest point of the underwater small ball at different horizontal speeds along with time by automatically extracting the motion parameters of the small ball and drawing a graph; asymmetric underwater cavitation edge features and motion parameters can be compared and analyzed through a graph drawn through a program, it is proved that the method can provide technical support for an underwater cavitation experiment, a large amount of time and energy are saved,and the experiment is effectively promoted to be carried out.

Description

technical field [0001] The invention relates to the field of ships and ocean engineering, in particular to a method for extracting edge features and motion parameters of an asymmetric water-entry cavity. Background technique [0002] When the structure enters the water at a certain initial velocity, a cavity will be formed around it, which is called the water entry cavity. The creation and collapse of cavities has a great influence on the structure. The cavitation created around the hull propellers can cause severe erosion, damage to the propellers and limited propeller drag. But cavitation also has a side that can be used. For example, the supercavitation torpedo drag reduction technology uses naturally occurring supercavitation to reduce the wetted area, thereby achieving the purpose of reducing frictional resistance. Therefore, it is of great practical significance to study the edge characteristics and motion parameters of water-entry cavitation bubbles. [0003] At pr...

Claims

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Application Information

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IPC IPC(8): G06T7/13G06T5/40G06T7/181
CPCG06T7/13G06T7/181G06T5/40G06T2207/10016
Inventor 孙铁志申建张桂勇王恒史崇镔
Owner DALIAN UNIV OF TECH