| The ski-jump energy dissipations are widely used in various water-discharging buildings.In order to increase the rapid dissipation of the discharge energy,different types of flip buckets have emerged.The old empirical formulas aren't suitable to be applied to describe the hydraulic characteristics of complex flip bucket.At present,domestic and foreign scholars mainly use theoretical formula derivation,model test and numerical simulation to study the hydraulic characteristics of the new energy dissipation.This paper firstly introduces the numerical simulation theory and method of ski-jump energy dissipation,and proposes a new type of lengthwise disorderly differential flip bucket for the problem that the ordinary differential flip bucket water tongue only has lateral spread.The main researches and the conclusions of this paper are as follows:(1)Following the design principle of the differential flip bucket,based on the downstream slope ratio and the curve of the original overflow weir,a new type lengthwise disorderly differential flip bucket with five different heights and low angles were designed.The high arc radius were also different.The original continuous selection of the engineering example was numerically simulated according to the check flood level and the design flood level.The calculated top flow velocity was basically consistent with the formula estimate,which verifies the feasibility of numerical simulation being applied to the new energy dissipation research.(2)Five kinds of new two-dimensional cross-sections of new type differential flip bucket were draw in CAD software,then imported them into Gambit software to stretch,and then 3D modelings were imported into ICEM CFD software for meshing.After quality checked,the meshes were calculated in the Fluent software.The post-processing software Tecplot was used to draw the water tongue flow diagram,the turbulent kinetic energy and the turbulent energy dissipation rate contour map of different profiles,and the Origin software was used to compare the pressure on the central axis of the high and low ridges and their boundary.(3)The water surface lines of the new energy dissipations were studied,the two high-canopy water tongues with the same width and width were set in the same model,and the picks were basically the same.The height of the pick is reduced with the decrease of the height of the high ridge,and the different height of high and low ridges are effective to increase the flushing area of the downstream riverbed by the discharge.The new ridge with a radius of 6m and 7m have farther water inlet points,which is beneficial to protect the foundation of the weir.(4)The turbulent kinetic energy and the turbulent energy dissipation rate of the new type of flip bucket were found.The excessively high and low ridge angles will cause the turbulent energy distribution to be affected by the shape of the high ridge.While the high ridge angle is32.51°,the new type flip bucket has a more uniform continuous strip-like turbulent energy distribution and a relatively small amount of turbulent energy.In addition,as the difference value between the height and the low angle is reduced,the distribution of the turbulent energy dissipation rate on the Y-axis is gradually reduced,and the difference of the pick-angle angle between 7° and 15° will cause the turbulent energy consumption under the high or low ridge.(5)The central axis pressure of the high ridge of the new type lengthwise disorderly shank is basically less than the central axis pressure of the low ridge,and the pressure of the high and low ridge boundary line are between them.High ridge radius which are too large or too small will cause large pressure,and a moderately high ridge will help to protect the drained building.The new type flip bucket with a radius of 6m and a high ridge angle of32.51° has the lowest pressure at the junction of the high and low ridges,and its maximum pressure value is farthest from the site. |
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