An asymptotic-preserving spectral method based on the radon transform for the PN approximation of radiative transfer

Thumbnail Image
Date
2018-01-01
Authors
Peterson, Lindsey
Major Professor
Advisor
James A. Rossmanith
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Authors
Research Projects
Organizational Units
Organizational Unit
Mathematics
Welcome to the exciting world of mathematics at Iowa State University. From cracking codes to modeling the spread of diseases, our program offers something for everyone. With a wide range of courses and research opportunities, you will have the chance to delve deep into the world of mathematics and discover your own unique talents and interests. Whether you dream of working for a top tech company, teaching at a prestigious university, or pursuing cutting-edge research, join us and discover the limitless potential of mathematics at Iowa State University!
Journal Issue
Is Version Of
Versions
Series
Department
Mathematics
Abstract

The equation of radiative transfer is an integro-differential equation in a five-dimensional phase space for the specific intensity of a radiation field. The equation models the transport of the radiation field, the energy loss due to absorption, the energy gain due to emission, and the redistribution of energy due to scattering. In the PN approximation, the specific intensity is replaced by a truncated spherical harmonics expansion, which results in replacing the five-dimensional integro-differential equation by a three-dimensional system of coupled partial differential equations. The resulting system of PDEs is hyperbolic, although the system becomes a parabolic heat equation in the vanishing mean-free path limit (i.e., the scattering dominated regime). A desirable feature of numerical methods for the PN system is that they remain stable and accurate if we fix the mesh parameters and take the vanishing mean-free path limit — in the literature this has been dubbed the “asymptotic-preserving” property. In this work, we develop a Chebyshev pseudo-spectral method for solving the PN system. The time-stepping is done using an L-stable scheme that guarantees that the overall numerical method is asymptotic-preserving. In the multidimensional implementation of the method, we make use of the Radon transform to reduce the computational complexity of the matrix inversion. Several numerical tests are presented in order to demonstrate the feasibility of the resulting method.

Comments
Description
Keywords
Citation
DOI
Source
Subject Categories
Copyright
Wed Aug 01 00:00:00 UTC 2018