Numerical Simulation of Hydrodynamics and Reaeration over a Stepped Spillway by the SPH Method

Hang Wan,Jingjie Feng,Carlo Gualtieri,Huixia Yang,Ran Li

doi:10.3390/w9080565

Hang Wan, Jingjie Feng + Show 3 more

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https://doi.org/10.3390/w9080565

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Abstract

Aerated flows are characterized by complex hydrodynamics and mass-transfer processes. As a Lagrangian method, smoothed particle hydrodynamics (SPH) has a significant advantage in tracking the air-water interface in turbulent flows. This paper presents the application of an SPH method to investigate hydrodynamics and reaeration over stepped spillways. In the SPH method, the entrainment of dissolved oxygen (DO) is studied using a multiphase mass transfer SPH method for reaeration. The numerical results are compared with the hydrodynamics data from Chanson and DO data from Cheng. The simulation results show that velocity distribution and the location of free-surface aeration inception agree with the experimental results. Compared with the experimental results, the distribution of DO concentration over the stepped spillway is consistent with the measurement results. The study shows that the two-phase DO mass transfer SPH model is reliable and reasonable for simulating the hydrodynamics characteristics and reaeration process.

Highlights

Predicting the aeration process has great significance for assessing the dissolved oxygen (DO)concentration, which is critical for the self-purification of polluted water [1]
The study shows that the two-phase DO mass transfer smoothed particle hydrodynamics (SPH) model is reliable and reasonable for simulating the hydrodynamics characteristics and reaeration process
The two-phase SPH mass transfer model accurately computes the reaeration of DO on the stepped spillway

Summary

Introduction

Predicting the aeration process has great significance for assessing the dissolved oxygen (DO)concentration, which is critical for the self-purification of polluted water [1]. The stepped spillway, as a type of important hydraulic structure, exhibits the dual functions of energy dissipation and the reaeration process. Few researchers paid attention to the mass transfer process between air and water over the spillway, until such analyses were conducted by Moog [6], and experiments were conducted by Cheng [7,8]). The range of the mass transfer between air and water is limited to a search radius. Computing and analyzing the mass transfer, the particle types of different phases should be defined. The critical function is employed within the scope of the search defined with different symbols. The critical function is employed within the scope of the radius. search radius.

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