Title page for ETD etd-08242006-093842


Type of Document Master's Thesis
Author Srivastava, Anurag
URN etd-08242006-093842
Title Stabilized Explicit Time Integration for Parallel Air Quality Models
Degree Master of Science
Department Computer Science
Advisory Committee
Advisor Name Title
Sandu, Adrian Committee Chair
Ribbens, Calvin J. Committee Member
Tafti, Danesh K. Committee Member
Keywords
  • Explcit time-stepping
  • Runge Kutta Chebyshev
  • STEM
  • Air Quality Models
  • Supercomputing
  • Parallel Computing
Date of Defense 2006-08-18
Availability unrestricted
Abstract
Air Quality Models are defined for prediction and simulation of air pollutant concentrations over a certain period of time. The predictions can be used in setting limits for the emission levels of industrial facilities. The input data for the air quality models are very large and encompass various environmental conditions like wind speed, turbulence, temperature and cloud density.

Most air quality models are based on advection-diffusion equations. These differential equations are moderately stiff and require appropriate techniques for fast integration over large intervals of time. Implicit time stepping techniques for solving differential equations being unconditionally stable are considered suitable for the solution. However, implicit time stepping techniques impose certain data dependencies that can cause the parallelization of air quality models to be inefficient.

The current approach uses Runge Kutta Chebyshev explicit method for solution of advection diffusion equations. It is found that even if the explicit method used is computationally more expensive in the serial execution, it takes lesser execution time when parallelized because of less complicated data dependencies presented by the explicit time-stepping. The implicit time-stepping on the other hand cannot be parallelized efficiently because of the inherent complicated data dependencies.

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