Level Set, Phase-Field, and Immersed Boundary Methods for Two-Phase Fluid Flows

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Haobo Hua ◽  
Jaemin Shin ◽  
Junseok Kim

In this paper, we review and compare the level set, phase-field, and immersed boundary methods for incompressible two-phase flows. The models are based on modified Navier–Stokes and interface evolution equations. We present the basic concepts behind these approaches and discuss the advantages and disadvantages of each method. We also present numerical solutions of the three methods and perform characteristic numerical experiments for two-phase fluid flows.

2011 ◽  
Vol 69 (4) ◽  
pp. 842-858 ◽  
Author(s):  
Yibao Li ◽  
Eunok Jung ◽  
Wanho Lee ◽  
Hyun Geun Lee ◽  
Junseok Kim

2017 ◽  
Vol 34 (3) ◽  
pp. 709-724 ◽  
Author(s):  
Amirmahdi Ghasemi ◽  
R. Nikbakhti ◽  
Amirreza Ghasemi ◽  
Faraz Hedayati ◽  
Amir Malvandi

Purpose A numerical method is developed to capture the interaction of solid object with two-phase flow with high density ratios. The current computational tool would be the first step of accurate modeling of wave energy converters in which the immense energy of the ocean can be extracted at low cost. Design/methodology/approach The full two-dimensional Navier–Stokes equations are discretized on a regular structured grid, and the two-step projection method along with multi-processing (OpenMP) is used to efficiently solve the flow equations. The level set and the immersed boundary methods are used to capture the free surface of a fluid and a solid object, respectively. The full two-dimensional Navier–Stokes equations are solved on a regular structured grid to resolve the flow field. Level set and immersed boundary methods are used to capture the free surface of liquid and solid object, respectively. A proper contact angle between the solid object and the fluid is used to enhance the accuracy of the advection of the mass and momentum of the fluids in three-phase cells. Findings The computational tool is verified based on numerical and experimental data with two scenarios: a cylinder falling into a rectangular domain due to gravity and a dam breaking in the presence of a fixed obstacle. In the former validation simulation, the accuracy of the immersed boundary method is verified. However, the accuracy of the level set method while the computational tool can model the high-density ratio is confirmed in the dam-breaking simulation. The results obtained from the current method are in good agreement with experimental data and other numerical studies. Practical/implications The computational tool is capable of being parallelized to reduce the computational cost; therefore, an OpenMP is used to solve the flow equations. Its application is seen in the following: wind energy conversion, interaction of solid object such as wind turbine with water waves, etc. Originality/value A high efficient CFD approach method is introduced to capture the interaction of solid object with a two-phase flow where they have high-density ratio. The current method has the ability to efficiently be parallelized.


Author(s):  
Guangfa Yao

Immersed boundary method has got increasing attention in modeling fluid-solid interaction using computational fluid dynamics due to its robustness and simplicity. It simulates fluid-solid interaction by adding a body force in the momentum equation without a body conforming mesh generation involved. Different immersed boundary methods have been presented and applied to solve fluid flow with immersed solid bodies. The main difference between these immersed boundary methods is how the body force is calculated. In this paper, a new immersed boundary method is proposed. The body force is calculated based on the volume fraction of the solid body immersed in fluid. Compared to the existing and similar methods, the new method develops a mechanism to calculate the body force and thereby more accurately resolve the physics on the solid-fluid interface. The solid body is represented using a level set that facilitates the calculation of the solid volume fraction. The body force derivation is presented and the method is validated against the test cases with existing analytical solutions or well established numerical solutions. A good match was reached.


Author(s):  
Guangfa Yao

Abstract Immersed boundary methods have gained increasing attention in modeling fluid-solid body interaction using non-body conforming computational fluid dynamics, due to their robustness and simplicity. They usually do this by adding a body force term in the momentum equation. The magnitude and direction of this body force ensure that the boundary condition on the solid-fluid interface is satisfied without invoking complicated body-conforming numerical methods to impose the boundary condition. The body force is usually calculated and imposed using some interpolation or extrapolation around the solid-fluid interface. It can also be calculated based on the solid volume fraction in the cells around the solid-fluid interface. Therefore, it is critical to have a robust method to represent or track arbitrary solid bodies immersed in a fluid field and facilitate the needed interpolation, extrapolation, or calculation of solid volume fraction. To that end, the level set method has been used as a robust method to represent and track arbitrary solid bodies in a fluid field. In the presented paper, the level set based approaches used to handle arbitrary solid bodies in a fluid field are reviewed, and a new higher order method is presented to resolve the solid-fluid interface using the given level sets at each grid point.


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