Method for measuring jet trajectory length air displacement of outer edge of model nappe under low-air-pressure environment

Abstract

The invention discloses a method for measuring the jet trajectory length air displacement of the outer edge of model nappe under the low-air-pressure environment. The method adopts a depression tank,firstly a measuring area is set, then a distance testing beam stretching across the front part of the model nappe is arranged in the measuring area, and thus the lower edge line of the distance testing beam is adjacent to the outer edge line of the model nappe; a camera is adopted to record the flow state of the model nappe located on the inclined front part of the distance testing beam; and a vacuum is formed in the depression tank, the flow state of the model nappe located on the inclined front part of the distance testing beam is online observed, if the phenomenon of splashing of a large number of water drops or the model nappe crossing the beam occurs, the distance between the lower edge line of the distance testing beam and the outer edge line of the model nappe is horizontally adjusted till the lower edge line of the distance testing beam is adjacent to the outer edge line of the model nappe, and the horizontal movement distance of the distance testing beam is the jet trajectorylength air displacement of the outer edge of the model nappe under the air pressure. The jet trajectory length air displacement of the outer edge of the model nappe under the low-air-pressure environment is measured by horizontally adjusting the position of the distance testing beam, the principle is simple and clear, the phenomenon is intuitive, and the cost is low.

Description

technical field [0001] The invention belongs to the technical field of dam engineering hydraulic tests, in particular to a method for measuring the aerial displacement of the outer edge of a water tongue of a low-pressure environment model. Background technique [0002] Southeastern Tibet is an important energy base for future hydropower development. In the study of flood discharge safety of high dams on the plateau, the movement trajectory of the discharge tongue is the basic data for determining whether the water tongue can be effectively returned to the groove, atomization prediction calculation, and energy dissipation and anti-scour design. Therefore, it is necessary to carry out research on how much the movement trajectory of the discharge water tongue is affected by the low air pressure, and whether the influence magnitude is within the range of the existing design safety factor. At present, some numerical simulation results point out that every time the ambient air p...

AI Technical Summary

Problems solved by technology

[0004] The pitch value fitted by the maximum pressure when the water tongue impacts the water cushion includes two parts: the air span and the water span, and it is difficult to effectively measure the influence of low air pressure on the model water span.

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