English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A data-driven projection-based reduced-order model (ROM) for nonlinearthermal radiative transfer (TRT) problems is presented. The TRT ROM isformulated by (i) a hierarchy of low-order quasidiffusion (aka variableEddington factor) equations for moments of the radiation intensity and (ii) thenormalized Boltzmann transport equation (BTE). The multilevel system of momentequations is derived by projection of the BTE onto a sequence of subspaceswhich represent elements of the phase space of the problem. Exact closure forthe moment equations is provided by the Eddington tensor. A Petrov-Galerkin(PG) projection of the normalized BTE is formulated using a proper orthogonaldecomposition (POD) basis representing the normalized radiation intensity overthe whole phase space and time. The Eddington tensor linearly depends on thesolution of the normalized BTE. By linear superposition of the POD basisfunctions, a low-rank expansion of the Eddington tensor is constructed withcoefficients defined by the PG projected normalized BTE. The material energybalance (MEB) equation is coupled with the effective grey low-order equationswhich exist on the same dimensional scale as the MEB equation. The resultingTRT ROM is structure and asymptotic preserving. A detailed analysis of the ROMis performed on the classical Fleck-Cummings (F-C) TRT multigroup test problemin 2D geometry. Numerical results are presented to demonstrate the ROM'seffectiveness in the simulation of radiation wave phenomena. The ROM is shownto produce solutions with sufficiently high accuracy while using low-rankapproximation of the normalized BTE solution. Essential physicalcharacteristics of supersonic radiation wave are preserved in the ROMsolutions.

A Reduced-Order Model for Nonlinear Radiative Transfer Problems Based on  Moment Equations and POD-Petrov-Galerkin Projection of the Normalized  Boltzmann Transport Equation