Hydraulic jump and choking of flow in pipe with a change of slope  

作　　者：Rui Zeng S.Samuel Li 

机构地区：[1]Department of Building,Civil and Environmental Engineering,Concordia University,Montreal,Canada

出　　处：《Journal of Hydrodynamics》2022年第6期1044-1066,共23页水动力学研究与进展B辑（英文版）

基　　金：received financial support from the Natural Sciences and Engineering Research Council of Canada through Discovery Grants held by S.S.Li.

摘　　要：This paper investigates hydraulic jumps in sloping pipes by means of wall-resolved large eddy simulation(LES).The purpose is to achieve an improved understanding of jump behaviours driven by pipe discharge and slope.The LES model predicts the hydraulic jump as a 3-D two-phase flow,with air as the gas phase and water as the liquid phase.The predictions yield instantaneous velocity and pressure fields as well as fluid volume fraction.The instantaneous flow variables allow ensemble averages,which quantify the internal structures and integral properties of the hydraulic jump.The predicted instantaneous velocity shows spectra in consistency with the well-known Kolmogorov−5/3 law.The ensemble averages of air and water velocities,free-surface profile,roller length and aeration length,compare well with available experimental data.The jump behaviours are complex.Some aspects such as free-surface fluctuation and jump-toe oscillation resemble the classical hydraulic jump on horizontal floors.Others like the 3-D distributions of core jet,vorticity and aeration are much more complicated.Depending on the pipe discharge and slope,the resulting jump can be a complete or an incomplete jump.The incomplete hydraulic jump causes choked flow downstream.This has severe consequences on drainage conditions in sewer pipes laid on sloping terrain.This paper proposes using the Okubo-Weiss parameter as a new way to subtly delineate the region of hydraulic jump.It is much more efficient and less ambiguous,compared with traditional visual inspections.

关 键 词：Hydraulic jump sloping pipe two-phase bubbly flow large eddy simulation(LES) choking of flow Okubo-Weiss parameter 

分 类 号：TV651.1[水利工程—水利水电工程]