This dissertation work is aimed at improving the capability and confidence in a modernized and improved version of Los Alamos National Laboratory's coupled atmospheric and wild- land fire dynamics model, Higrad-Firetec. Higrad is the hydrodynamics component of this large eddy simulation model that solves the three dimensional, fully compressible Navier- Stokes equations, incorporating a dynamic eddy viscosity formulation through a two-scale turbulence closure scheme. Firetec is the vegetation, drag forcing, and combustion physics portion that is integrated with Higrad. The modern version of Higrad-Firetec incorporates multiple numerical methodologies and high performance computing aspects which combine to yield a unique tool capable of augmenting theoretical and observational investigations in order to better understand the multi-scale, multi-phase, and multi-physics, phenomena in- volved in coupled atmospheric and environmental dynamics. More specifically, the current work includes extended functionality and validation efforts targeting component processes in coupled atmospheric and wildland fire scenarios. Since observational data of sufficient quality and resolution to validate the fully coupled atmosphere-wildfire scenario simply does not exist, we instead seek to validate components of the full prohibitively convoluted pro- cess. This manuscript provides first, an introduction and background into the application space of Higrad-Firetec. Second we document the model formulation, solution procedure, and a simple scalar transport verification exercise. Third, we perform a validate model results against observational data for time averaged flow field metrics in and above four idealized forest canopies. Fourth, we carry out a validation effort for the non-buoyant jet in a crossflow scenario (to which an analogy can be made for atmosphere-wildfire interactions) comparing model results to laboratory data of both steady-in-time and unsteady-in- time metrics. Finally, an extension of model multi-phase physics is implemented, allowing for the representation of multiple collocated fuels as separately evolving constituents lead- ing to differences resulting rate of spread and total burned area. In combination these efforts demonstrate improved capability, increased validation of component functionality, and unique applicability the Higrad-Firetec modeling framework. As a result this work provides a substantially more robust foundation for future new, more widely acceptable investigations into the complexities of coupled atmospheric and wildland fire behavior. / A Dissertation submitted to the Program in Geophysical Fluid Dynamics in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2013. / November 12, 2013. / Atmospheric, Collocated Fuels, Fuel Heterogeneity, Numerical Modeling, Wildfire / Includes bibliographical references. / Doron Nof, Professor Directing Thesis; Eric Chicken, University Representative; Rodman R. Linn, Committee Member; Ming Ye, Committee Member; Ruby Krishnamurti, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_185162 |
| Contributors | Sauer, Jeremy A. (authoraut), Nof, Doron (professor directing thesis), Chicken, Eric (university representative), Linn, Rodman R. (committee member), Ye, Ming (committee member), Krishnamurti, Ruby (committee member), Program in Geophysical Fluid Dynamics (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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