Level-Set Based Sharp Interface Method for Dendrite Solidification

2003 ◽  
Author(s):  
Yi Yang ◽  
Linhbao Tran ◽  
H. Udaykumar
Keyword(s):  
Level Set ◽  
Sharp Interface ◽  
Sharp Interface Method ◽  
Dendrite Solidification

A Sharp Interface Method for Compressible Multi-Phase Flows Based on the Cut Cell and Ghost Fluid Methods

2017 ◽  
Vol 9 (5) ◽  
pp. 1052-1075 ◽  
Author(s):  
Xiao Bai ◽  
Xiaolong Deng
Keyword(s):  
Level Set ◽  
Sharp Interface ◽  
Reconstruction Method ◽  
Topological Change ◽  
Sharp Interface Method ◽  
Cut Cell ◽  
Straight Line ◽  
Variable Domains ◽  
Mixing Method ◽  
Multi Phase

AbstractA new sharp interface method with the combination of Ghost Fluid Method (GFM) and Cut Cell scheme is developed to study compressible multi-phase flows with clear interfaces. Straight-line cutting is applied on the cells passed by the interface. A new real-ghost mixing method is presented and applied around the cut cells to deal with very small cut cells. A cut face reconstruction method similar to volume of fluid is applied to deal with topological change problems. A high order Level Set (LS) method is applied to evolve the free interface, with the Level Set velocities from exact Riemann solver on the cut faces. Various 1D and 2D numerical examples are tested to show the robustness and ability of the present method in wide flow variable domains. This method benefits from cut cell on the sharp interface description, shows good conservation performance, and does not have the topological change difficulty of the full cut cell method presented in Chang, Deng & Theofanous, J. Comput. Phys., 242 (2013), pp. 946–990.

Comparison of Sharp Interface and Smoothed Profile Methods for Laminar Flow Analysis Over Stationary and Moving Boundaries

2014 ◽  
Author(s):  
Fazlolah Mohaghegh ◽  
John Mousel ◽  
H. S. Udaykumar
Keyword(s):  
Drag Coefficient ◽  
Immersed Boundary Method ◽  
Flow Analysis ◽  
Sharp Interface ◽  
Wake Flow ◽  
Immersed Boundary ◽  
Particulate Flows ◽  
Sharp Interface Method ◽  
Smoothed Profile Method ◽  
Coarse Grids

This study is a comparison of two techniques for simulation of particulate flows on fixed Cartesian grids: Sharp interface Method (SIM) (Udaykumar et al., 2001, 2002, 2003) and a modified version of Immersed Boundary Method (Peskin, 1977) (IBM) known as Smoothed Profile Method (SPM) (Nakayama and Yamamoto, 2005; Luo et. al, 2009). Different cases were studied includes flow over one or two moving and stationary particles. Predictions of the drag coefficient shows that SPM and SIM are very close to the experiments. SIM slightly under-predicts the value of the drag coefficient while SPM has a small over-estimation. Moreover, SPM is more accurate on coarse grids. However, with refinement of the grid SIM approaches the exact values very fast leading to better results on fine grids. Flow pattern and vortex structures of SPM and SIM are almost the same. Both methods are capable of analyzing the wake flow. Unlike SIM, SPM is able to simulate the flow when two particles are in contact. When two particles are in motion and are very close in a way that the two interfaces overlap, SPM shows a repulsion force between two spheres which reduces the accuracy in comparison with SIM. However, SPM can achieve the collision of two particles without problem.

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