Modeling scalar dispersion in urban environments
Abstract/Contents
- Abstract
- The expansion of High Performance Computing (HPC) capabilities is allowing Computational Fluid Dynamics (CFD) methods to be applied to model dispersion in urban areas. The problem of dispersion in such environments is of growing concern to governmental organizations and first responders interested in mitigating the effects of a terrorist attack or intentional release of a harmful substance. The fundamental physical phenomena underlying the dispersion processes to be modeled is that of turbulent mixing and transport. The processes are inherently of a multi-scale nature as releases proceed from localized sources to envelop larger areas. Adding to the modeling challenge within an urban environment is that complex geometries create strong anisotropies which traditional reduced-order modeling approaches fail to capture. In the first portion of this work, the computational infrastructure is assembled to enable simulations of dispersion in real urban environments. An Oklahoma City validation case is presented and compared with available experimental tracer data. Next, high-fidelity Direct Numerical Simulations (DNS) and Large-Eddy Simulations (LES) of dispersion in "building block" geometries are performed. The results are used to study dispersion flow physics within an urban-like canopy from the building to neighborhood scales. Additionally, the high-fidelity datasets are used to evaluate and drive improvements in the Reynolds-Averaged Navier-Stokes (RANS) modeling approach. Algebraic models are shown to yield an improved representation of the turbulent scalar flux as compared to the standard Schmidt number approach. It is shown that these scalar flux models can be combined with eddy-viscosity type turbulence closures when a better representation of normal Reynolds stress anisotropy is provided. The v2-f model is adapted to provide such a representation and improvement is demonstrated in predicting the scalar field from a point source release.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Philips, David Alexander |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering |
| Primary advisor | Iaccarino, Gianluca |
| Thesis advisor | Iaccarino, Gianluca |
| Thesis advisor | Monismith, Stephen Gene |
| Thesis advisor | Shaqfeh, Eric S. G. (Eric Stefan Garrido) |
| Advisor | Monismith, Stephen Gene |
| Advisor | Shaqfeh, Eric S. G. (Eric Stefan Garrido) |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | David Alexander Philips. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by David Alexander Philips
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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