Suppress Numerical Oscillations in Transient Mixed Flow Simulations with a Modified HLL Solver

Transition between free-surface and pressurized flows is a crucial phenomenon in many hydraulic systems. During simulation of such phenomenon, severe numerical oscillations may appear behind filling-bores, causing unphysical pressure variations and computation failure. This paper reviews existing os...

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Bibliographic Details
Published in:Water (Basel) 2020-05, Vol.12 (5), p.1245
Main Authors: Mao, Zhonghao, Guan, Guanghua, Yang, Zhonghua
Format: Article
Language:English
Subjects:
Hydraulic flow
Numerical analysis
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Summary:Transition between free-surface and pressurized flows is a crucial phenomenon in many hydraulic systems. During simulation of such phenomenon, severe numerical oscillations may appear behind filling-bores, causing unphysical pressure variations and computation failure. This paper reviews existing oscillation-suppressing methods, while only one of them can obtain a stable result under a realistic acoustic wave speed. We derive a new oscillation-suppressing method with first-order accuracy. This simple method contains two parameters, Pa and Pb, and their values can be determined easily. It can sufficiently suppress numerical oscillations under an acoustic wave speed of 1000 ms−1. Good agreement is found between simulation results and analytical results or experimental data. This paper can help readers to choose an appropriate oscillation-suppressing method for numerical simulations of flow regime transition under a realistic acoustic wave speed.
ISSN:2073-4441
2073-4441
DOI:10.3390/w12051245