scholarly journals Numerical Simulation of Cavitation and Aeration in Discharge Gated Tunnel of a Dam Based on the VOF Method

2011 ◽  
Vol 110-116 ◽  
pp. 2754-2761
Author(s):  
Razieh Jalalabadi ◽  
Norouz Mohammad Nouri
Keyword(s):  
Numerical Simulation ◽  
Cavitation Erosion ◽  
Vof Method ◽  
Bubbly Flows ◽  
Hydraulic Structures ◽  
Cavitating Flows ◽  
Effective Protection ◽  
Two Phase ◽  
Cavitation Inception ◽  
Numerical Studies

Cavitation, usually known as a destructive phenomenon, involves turbulent unsteady two-phase flow. Having such features, cavitating flows have been turned to a challenging topic in numerical studies and many researches are being done for better understanding of bubbly flows and proposing solutions to reduce its consequent destructive effects. Aeration may be regarded as an effective protection against cavitation erosion in many hydraulic structures, like gated tunnels. The paper concerns numerical simulation of flow in discharge gated tunnel of a dam using RNG model coupled with the volume of fluid (VOF) method and the zone which is susceptible of cavitation inception in the tunnel is predicted. Then a vent is considered in the mentioned zone for aeration and the numerical simulation is done again to study the effects of aeration. The results show that aeration is an impressively useful method to exclude cavitation in mentioned tunnels.

CFD Modeling of Two-Phase Gas-Liquid Slug Flow Using VOF Method in Microchannels

2009 ◽  
Author(s):  
A. Mehdizadeh ◽  
S. A. Sherif ◽  
W. E. Lear
Keyword(s):  
Numerical Simulation ◽  
Liquid Film ◽  
Slug Flow ◽  
Thin Liquid Film ◽  
Liquid Films ◽  
Vof Method ◽  
Cfd Modeling ◽  
Two Phase ◽  
Mesh Resolution ◽  
Gas Volume

Despite of the fact that numerical simulation of two-phase flows in microchannels has been attempted by many investigators, most efforts seem to have failed in correctly capturing the flow physics, especially the slug flow regime characteristics. The presence of a thin liquid film in the order of 10 μm around the bubble (sometimes called gas pocket or gas slug) may be a contributing factor to the above difficulty. Typically, liquid films have a significant effect on the flow field. Thus, there is a strong motivation to employ numerical simulation methods in order to avoid some of the experimental difficulties. In this paper, the characteristics of two-phase slug flows in microchannels are calculated with the help of the Volume-of-Fluid (VOF) method. Formation of the slugs for different superficial velocities, Capillary numbers, and gas volume fractions are investigated. The minimum mesh resolution required to capture the liquid film surrounding the gas bubble is reported employing a dynamic mesh adaption methodology with interface tracking. Results are shown to be in good agreement with experimental data and empirical correlations.

Solitary wave breaking on sloping beaches: 2-D two phase flow numerical simulation by SL-VOF method

2001 ◽  
Vol 20 (1) ◽  
pp. 57-74 ◽  
Author(s):  
Stephan Guignard ◽  
Richard Marcer ◽  
Vincent Rey ◽  
Christian Kharif ◽  
Philippe Fraunié
Keyword(s):  
Numerical Simulation ◽  
Solitary Wave ◽  
Wave Breaking ◽  
Two Phase Flow ◽  
Vof Method ◽  
Phase Flow ◽  
Two Phase

scholarly journals On the Two-phase Fractional Stefan Problem

2020 ◽  
Vol 20 (2) ◽  
pp. 437-458 ◽  
Author(s):  
Félix del Teso ◽  
Jørgen Endal ◽  
Juan Luis Vázquez
Keyword(s):  
Free Boundary ◽  
Stefan Problem ◽  
Free Boundary Problems ◽  
Classical Problem ◽  
Nonlocal Diffusion ◽  
Two Phase ◽  
Boundary Problems ◽  
Numerical Studies ◽  
The One ◽  
Evolution Type

AbstractThe classical Stefan problem is one of the most studied free boundary problems of evolution type. Recently, there has been interest in treating the corresponding free boundary problem with nonlocal diffusion. We start the paper by reviewing the main properties of the classical problem that are of interest to us. Then we introduce the fractional Stefan problem and develop the basic theory. After that we center our attention on selfsimilar solutions, their properties and consequences. We first discuss the results of the one-phase fractional Stefan problem, which have recently been studied by the authors. Finally, we address the theory of the two-phase fractional Stefan problem, which contains the main original contributions of this paper. Rigorous numerical studies support our results and claims.

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