A method for locating the separation point of shock train
A separation point and shock wave technology, applied in the testing of machines/structural components, instruments, measuring devices, etc., can solve the problem that a large amount of schlieren image data has not been effectively used, and achieve the effect of improving the utilization rate of research
Active Publication Date: 2019-01-11
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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[0004] Aiming at the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a method for locating the separation point of the shock train, so as to solve the problem that usually only a small number of images of typical flow characteristics in schlieren are used to display the shock train structure and For the qualitative analysis of the law of motion, a large amount of schlieren image data has not been effectively utilized. This method extracts and calculates the position of the separation point in the schlieren image and gives accurate coordinates to achieve a large number of schlieren images. Quantitative digital processing of schlieren data to improve utilization of schlieren image data
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[0018] In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the embodiments and the drawings, and the content mentioned in the embodiments does not limit the present invention.
[0019] The method for locating the separation point of the shock train of the present invention includes the steps of setting the gray matrix analysis range, calculating and analyzing the column vector characteristics of the gray matrix, establishing the criterion, and capturing and locating the gray vector in the image that matches the wall separation feature , Use its characteristic point coordinates as the separation point coordinates to realize the location of the separation point; the specific steps are as follows:
[0020] 1) Select the analysis window and extract the grayscale matrix of the window to ensure that any position that the shock train separation point can reach is within the window;
[0021] 2) Based ...
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The invention discloses a positioning method for a shock train separation point, and the method is used for the technology of supersonic / high sound velocity flow field schlieren visualization. The method comprises the steps: extracting the gray scale of a schlieren image, analyzing the features of a separation point column vector, capturing and locating a gray scale vector according with the features in the image, determining the coordinates of a feature point, enabling the coordinates to serve as the coordinates of the separation point, and completing the positioning of the separation point. According to the invention, a calculation model of wall surface separation point gray scale features is given, and the method can be used for precisely capturing a separation position of a shock train at any moment, achieves the digitalized quantitative processing of batch schlieren data, and greatly improves the utilization rate of schlieren image data in the research area.
Description
Technical field [0001] The invention belongs to the technical field of supersonic flow field measurement and display technology, and specifically refers to a shock string separation point positioning method used in supersonic flow field schlieren display. Background technique [0002] Shock train is a kind of complex flow phenomenon with shock wave / surfacing layer interference as the main feature in the process of supersonic / hypersonic airflow during deceleration and pressurization. The mutual interference between the shock wave and the boundary layer causes the morphology of the boundary layer to change, resulting in separation and reattachment, forming an extremely complex shock train or pseudo-shock structure in the pipeline. This kind of flow structure is widely present in the air-breathing hypersonic aircraft inlet / isolation section, supersonic wind tunnel diffuser and supersonic jet device, and its flow characteristics are closely related to the aerodynamic design and perfo...
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IPC IPC(8): G01M9/06
CPCG01M9/06
Inventor 王成鹏薛龙生程川焦运徐培程克明
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS