A novel diffuse-interface model and numerical methods for compressible turbulent two-phase flows and scalar transport
Abstract/Contents
- Abstract
- Compressible two-phase flows and the transport of scalars in two-phase flows have a wide range of applications in natural and engineering processes. In this thesis we first present a novel diffuse-interface model for the simulation of compressible two-phase flows. We start with the baseline five-equation model that consists of equations for the transport of volume fraction, mass of each phase, momentum, and total energy. It is known that this model cannot be used with a non-dissipative scheme as is, and the direct solution of these equations with a dissipative scheme results in artificial diffusion of the interface which results in poor accuracy. We, therefore, propose interface-regularization (diffusion--sharpening) terms to this five-equation model in such a way that the resulting model can now be used with a non-dissipative central scheme, and the model also maintains the discrete conservation of mass of each phase, momentum, and total energy of the system. For stable numerical simulations of compressible flows, it is known that a discrete entropy condition needs to be satisfied, and the discrete conservation of kinetic energy alone is not a sufficient condition, unlike in incompressible flows. To achieve this, we first propose discrete consistency conditions between the numerical fluxes, and then present a set of numerical fluxes--which satisfies these consistency conditions--that results in an exact discrete conservation of kinetic energy and approximate conservation of entropy (a KEEP scheme) in the absence of pressure work, viscosity, and thermal diffusion effects. Next, we also propose a novel scalar-transport model for the simulation of scalar quantities in two-phase flows. In a two-phase flow, the scalar quantities typically have very different diffusivities in the two phases, which results in effective confinement of the scalar quantities in one of the phases, in the time scales of interest. This confinement of the scalars leads to the formation of sharp gradients of the scalar concentration values at the interface and could result in artificial numerical leakage of the scalar and negative values for the scalar concentration values, presenting a serious challenge for its numerical simulations. To overcome this challenge, we propose a new consistent scalar-transport model that prevents artificial numerical leakage of the scalar at the interface. The proposed model also maintains the positivity property of the scalar concentration field, a physical realizability requirement for the simulation of scalars. Finally, we present numerical simulations to verify and validate the models presented in this work in a wide range of settings and regimes, spanning laminar to turbulent flows; and assess the accuracy, robustness, and scalability of the models.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Suresh, Suhas Jain |
|---|---|
| Degree supervisor | Moin, Parviz |
| Thesis advisor | Moin, Parviz |
| Thesis advisor | Lele, Sanjiva K. (Sanjiva Keshava), 1958- |
| Thesis advisor | Mani, Ali, (Professor of mechanical engineering) |
| Thesis advisor | Urzary Lobo, Javier, 1982- |
| Degree committee member | Lele, Sanjiva K. (Sanjiva Keshava), 1958- |
| Degree committee member | Mani, Ali, (Professor of mechanical engineering) |
| Degree committee member | Urzary Lobo, Javier, 1982- |
| Associated with | Stanford University, Department of Mechanical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Suhas Jain Suresh. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2022. |
| Location | https://purl.stanford.edu/kj049bf7436 |
Access conditions
- Copyright
- © 2021 by Suhas Jain Suresh
- License
- This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).
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