A Cut-Cell Based Ghost Fluid Method for Multi-Component Compressible Flows

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Liu, C. (2020). A Cut-Cell Based Ghost Fluid Method for Multi-Component Compressible Flows. Unc Charlotte Electronic Theses And Dissertations.
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Abstract

Multi-material compressible flows are observed in several applications of practical relevance including combustion, cavitation and shock lithotripsy. To solve such flows numerically with improved efficiency and accuracy, the use of the Ghost Fluid Method (GFM) and its derivatives have been adopted widely. However, certain drawbacks of the ghost fluid approach such as overheating errors, and the appearance of unphysical oscillations of density and pressure are well known and have been documented in the literature. In this work, a cut-cell based GFM approach is proposed to accurately solve for the fluid state at the multi-material interface, while the location of the interface is tracked by a second-order level set scheme. The modified GFM was implemented in IMPACT, a multi-material, shock-physics code. The improvements to the GFM are validated through a wide range of simulations including multi-material flow problems, 1D shock problems, 2D shock-induced bubble collapse in water/air and the 2D Richtmyer-Meshkov instability. In addition, the efficiency of the numerical solver is improved with the implementation of a blocked-structured Adaptive Mesh Refinement (AMR) scheme. We find the AMR implementation enhances computational efficiency, while improving the mass conservation properties of the level set scheme.

Details
Author

Liu, Chen

Title

A Cut-Cell Based Ghost Fluid Method for Multi-Component Compressible Flows

Physical Description

1 online resource (88 pages) : PDF

Date

2020

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

Multi-material compressible flows are observed in several applications of practical relevance including combustion, cavitation and shock lithotripsy. To solve such flows numerically with improved efficiency and accuracy, the use of the Ghost Fluid Method (GFM) and its derivatives have been adopted widely. However, certain drawbacks of the ghost fluid approach such as overheating errors, and the appearance of unphysical oscillations of density and pressure are well known and have been documented in the literature. In this work, a cut-cell based GFM approach is proposed to accurately solve for the fluid state at the multi-material interface, while the location of the interface is tracked by a second-order level set scheme. The modified GFM was implemented in IMPACT, a multi-material, shock-physics code. The improvements to the GFM are validated through a wide range of simulations including multi-material flow problems, 1D shock problems, 2D shock-induced bubble collapse in water/air and the 2D Richtmyer-Meshkov instability. In addition, the efficiency of the numerical solver is improved with the implementation of a blocked-structured Adaptive Mesh Refinement (AMR) scheme. We find the AMR implementation enhances computational efficiency, while improving the mass conservation properties of the level set scheme.

Genre

masters theses

Subjects--Topics

Fluid mechanics

Degree

M.S.

Keywords

CFD
Compressible Flow
Ghost Fluid Method
Level Set Method
Multiphase Flow

Subject Area

Mechanical Engineering

Advisor(s)

Ramaprabhu, Praveen

Committee Members

Cherukuri, Harish
Deng, Shaozhong

Degree Note

Thesis (M.S.)--University of North Carolina at Charlotte, 2020.

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Rights Holder Information

Copyright is held by the author unless otherwise indicated.

Identifier

Liu_uncc_0694N_12621

Permalink

http://hdl.handle.net/20.500.13093/etd:2263