| The research on siltation promotion measures has very important theoretical and practical significance in river bank protection,land reclamation and other projects,and the research on siltation promotion measures with high siltation promotion and high practicality is not waiting for me.This paper proposes a perforated silt accelerating plate structure.Through the water tank test,a three-dimensional perforated silt accelerating plate numerical model is established based on the RNG k-? turbulence model to analyze different flow rates,open porosity,number of holes,and plate spacing.The change characteristics of the velocity field,turbulence field,bed surface shear stress,and deceleration rate around the perforated silt-promoting plate under the plate combination form,the main conclusions are as follows:(1)Under the same opening rate,different numbers of openings have little effect on the flow velocity in front of the silt-promoting plate with openings,and the flow velocity distribution law is basically the same.The effect of double water depth is relatively small,and the water depth of ten times is basically restored to stability,and the range of action of a single perforated plate is about ten times of water depth.When the number of holes is the same under different opening ratios,the flow velocity in front of the plate increases with the increase of the opening ratio.Within three times of the water depth behind the plate,when the opening ratio is 30%and 40%,the flow velocity ratio near the bottom is 46%,56%is small and the area with high flow velocity is distributed on the surface layer.(2)In terms of water level,recirculation zone,and deceleration effect of a single perforated silt promotion plate with different opening rates,the change of water level basically shows a linear increase with the decrease of opening rate,and the backflow strength after the plate gradually weakens with the increase of opening rate.The height of the recirculation zone decreases with the increase of the opening rate.The deceleration effect is different under different aperture ratios.When the aperture ratio is 30%and the number of holes is 5,the overall deceleration effect is the best,and the formula for the optimal aperture ratio and aperture area is fitted.(3)Under different flow rates,the maximum bottom flow velocity and the maximum surface flow velocity basically showed a linear increase trend with the increase of the flow rate.The change of the flow rate has no obvious effect on the length and width of the return zone after the opening of the silt-promoting plate.The water level drop and pressure difference before and after the plate increase with the increase of the flow rate and increase rapidly.The turbulence parameter and bed surface shear force increase with the increase of the flow rate,the increase is slow when the flow rate is 0.06 m3/s,and the increase is obvious when the flow rate exceeds 0.06 m3/s.In terms of the deceleration effect of different flow rates,when the flow rate is less than 0.036 m3/s,the effect of arranging the silt-promoting plate with openings is worse,and better deceleration effects can be achieved after the front plate of the plate exceeds 0.036 m3/s.(4)The analysis of the flow field around the silt-promoting plate with five different openings and two different combinations shows that the change of the plate spacing has little effect on the flow velocity field.In terms of turbulence,the flow field around the silt-promoting plate with openings is analyzed.,The maximum turbulence intensity appears near the second plate at a distance of 6 times the plate height(6L)and 8 times the plate height(8L)between the perforated plates.In terms of deceleration effect,both the combination A plate and the combination B plate can have a better deceleration effect in front of the plate.When the plate spacing is 8L,the combination A plate and the combination B plate have the same deceleration effect,and the plate spacing 6L-8L is recommended. |
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