scholarly journals A diffuse domain method for two-phase flows with large density ratio in complex geometries

2020 ◽  
Vol 907 ◽  
Author(s):  
Zhenlin Guo ◽  
Fei Yu ◽  
Ping Lin ◽  
Steven Wise ◽  
John Lowengrub
Keyword(s):  
Density Ratio ◽  
Complex Geometries ◽  
Two Phase Flows ◽  
Two Phase ◽  
Large Density ◽  
Domain Method ◽  
Large Density Ratio

Abstract

scholarly journals Phase-field-based lattice Boltzmann modeling of large-density-ratio two-phase flows

2018 ◽  
Vol 97 (3) ◽  
Author(s):  
Hong Liang ◽  
Jiangrong Xu ◽  
Jiangxing Chen ◽  
Huili Wang ◽  
Zhenhua Chai ◽  
...  
Keyword(s):  
Phase Field ◽  
Lattice Boltzmann ◽  
Density Ratio ◽  
Two Phase Flows ◽  
Two Phase ◽  
Large Density ◽  
Large Density Ratio ◽  
Lattice Boltzmann Modeling

A Preconditioned Implicit Free-Surface Capture Scheme for Large Density Ratio on Tetrahedral Grids

2012 ◽  
Vol 11 (1) ◽  
pp. 215-248 ◽  
Author(s):  
Xin Lv ◽  
Qingping Zou ◽  
D.E. Reeve ◽  
Yong Zhao
Keyword(s):  
Free Surface ◽  
Density Ratio ◽  
Three Dimensional ◽  
Integration Scheme ◽  
Two Phase ◽  
Fully Implicit ◽  
Large Density ◽  
Multi Stage ◽  
Tetrahedral Grids ◽  
Large Density Ratio

AbstractWe present a three dimensional preconditioned implicit free-surface capture scheme on tetrahedral grids. The current scheme improves our recently reported method [10] in several aspects. Specifically, we modified the original eigensystem by applying a preconditioning matrix so that the new eigensystem is virtually independent of density ratio, which is typically large for practical two-phase problems. Further, we replaced the explicit multi-stage Runge-Kutta method by a fully implicit Euler integration scheme for the Navier-Stokes (NS) solver and the Volume of Fluids (VOF) equation is now solved with a second order Crank-Nicolson implicit scheme to reduce the numerical diffusion effect. The preconditioned restarted Generalized Minimal RESidual method (GMRES) is then employed to solve the resulting linear system. The validation studies show that with these modifications, the method has improved stability and accuracy when dealing with large density ratio two-phase problems.

LBM Application in Two-Phase Fluid Flow with Large Density Ratio

2012 ◽  
Vol 476-478 ◽  
pp. 871-875
Author(s):  
Qing Ming Chang ◽  
Yin Kai Yang ◽  
Jing Yuan ◽  
Xia Chen ◽  
Min Zhang
Keyword(s):  
Gravity Wave ◽  
Numerical Solutions ◽  
Density Ratio ◽  
Surface Tension Force ◽  
Analytic Solutions ◽  
Lattice Boltzmann Model ◽  
Two Phase ◽  
Large Density ◽  
Large Density Ratio ◽  
Parasitic Currents

In this paper, a stable lattice Boltzmann model (LBM) based on non-ideal gases is presented for simulation of incompressible two-phase flows with large density ratio. To reduce the parasitic currents across the interface and correspondingly increase the numerical stability, the stress and potential forms of the surface tension force is employed. The applications to a stationary bubble and capillary-gravity wave with density ratio 1000 are given to verify this model. The numerical solutions is agree well with analytic solutions of the Laplace's law and capillary-gravity wave.

Efficient two-phase mass-conserving level set method for simulation of incompressible turbulent free surface flows with large density ratio

2016 ◽  
Vol 136 ◽  
pp. 212-227 ◽  
Author(s):  
J.M. Cubos-Ramírez ◽  
J. Ramírez-Cruz ◽  
M. Salinas-Vázquez ◽  
W. Vicente-Rodríguez ◽  
E. Martinez-Espinosa ◽  
...  
Keyword(s):  
Free Surface ◽  
Level Set Method ◽  
Level Set ◽  
Density Ratio ◽  
Free Surface Flows ◽  
Two Phase ◽  
Surface Flows ◽  
Large Density ◽  
Large Density Ratio

A Novel Numerical Scheme for Outlet Boundary Conditions in Large Density Ratio Lattice Boltzmann Model

2016 ◽  
Author(s):  
Long Li ◽  
Yongwen Liu
Keyword(s):  
Boundary Condition ◽  
Lattice Boltzmann ◽  
Numerical Scheme ◽  
Density Ratio ◽  
Two Phase ◽  
Droplet Shape ◽  
Large Density ◽  
Large Velocity ◽  
Large Density Ratio ◽  
Outlet Boundary Condition

In the past decades, the Lattice Boltzmann method has gained much success in variety fields especially in multiphase flow, porous media flow, and other complex flow, and become a promising method for computational fluid dynamic (CFD). The outlet boundary condition (OBC) and its numerical scheme are critical issues in CFD, which may influence the accuracy and stability of the calculation. The common OBCs i.e. Neumann boundary condition (NBC), extrapolation boundary condition (EBC), and convection boundary condition (CBC), which have been widely investigated in single-phase LB model, have rarely been investigated in multiphase LB model. The previous research on the OBCs for two-phase LB model only aims at small density ratio. While in most industrial applications, the density ratio often ranges from a hundred to a thousand, and a large density ratio would bring some problems such as parasitic current and bad stability in LB method. Lee and Fischer have proposed an improved LB model which is suitable for large density ratio two-phase flow. In order to assess the OBCs for large density ratio LB model, the OBCs are investigated. And it is found that the existing OBC numerical scheme cannot be directly applied to the large density ratio LB model. In present study, a novel numerical scheme for the OBCs is proposed assuming that the outlet velocity is gained by the outlet boundary condition instead of the momentum equation which is an improvement of previous scheme, and it can be used in large density ratio LB model. The performance of the proposed OBC scheme is examined for different density ratios. The results show that the proposed OBC scheme could converge in a stable manner. Comparing with the reference flow condition, the CBC scheme shows a better performance than the NBC scheme and the EBC scheme. The NBC scheme would lead a large droplet deformation, large velocity peaks at the outlet, and large errors for both small and large density ratio. And the EBC scheme keeps a good droplet shape, but it would lead large velocity peaks at the outlet and large error when large density ratio is considered. The CBC scheme always shows superior performance including a good droplet shape, smooth outlet velocity profile, and small errors no matter whether the density ratio is small or large. Hence the CBC scheme could be applied in large density ratio LB model for the outlet boundary condition, which has a good accuracy and stability in the calculation.

Standard WCSPH for Free-Surface Multi-Phase Flows with a Large Density Ratio

2018 ◽  
Vol 01 (02) ◽  
pp. 1840001 ◽  
Author(s):  
Sauro Manenti
Keyword(s):  
Free Surface ◽  
Density Ratio ◽  
Computational Cost ◽  
Computational Effort ◽  
Dynamic Features ◽  
Particle Volume ◽  
Two Phase ◽  
Large Density ◽  
Large Density Ratio ◽  
Multi Phase

The standard weakly compressible Smoothed Particle Hydrodynamics (WCSPH) is successfully applied to multi-phase problems involving fluids with similar densities, but when density ratio increases at some order of magnitude, serious instability phenomena occur at the interface. Several remedies have been proposed based on numerical correctives that deviate from standard formulation, increasing the algorithm complexity and, sometimes, the computational cost. In this study, the standard SPH has been adapted to treat free-surface multi-phase flows with a large density ratio through a modified form of the governing equations which is based on the specific volume (i.e. the inverse of particle volume) instead of density: the former is continuous across the fluid interface while the latter is not and generates numerical instability. Interface sharpness is assured without cohesion forces; kernel truncation at the interface is avoided. The model, relatively simple to implement, is tested by simulating two-phase dam breaking for two configurations: kinematic and dynamic features are compared with reference data showing good agreement despite the reduced computational effort.

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