A hybrid transport-diffusion method for 2D transport problems with diffusive subdomains

Reduced order models for thermal radiative transfer problems based on moment equations and data-driven approximations of the Eddington tensor

“…For the model developed here, the Eddington tensor is computed from approximate solution data to the TRT problem generated with radiation-diffusion models. It has been previously shown that the solution of the Boltzmann transport equation computed with a scattering source term evaluated by a diffusion solution yields a sufficiently accurate shape function for estimation of the Eddington tensor in linear problems [73,74]. An extension of this idea to the nonlinear TRT problem is to use the material temperatures evaluated with a radiation-diffusion model to compute the opacity and emission source in the radiative transfer equation (RTE).…”

Multischeme transport with upwinding for Rattlesnake code

“…Multischeme transport is a concept in which the spatial solution domain is divided into subdomains where various discretization schemes with different angular, space, energy resolutions can be applied [1][2][3][4][5][6][7][8]. It is noted that we stop using the name previously use in Rattlesnake methods development, multiscale, to avoid confusions in multiphysics environment, where multiscale is frequently used in materials modeling.…”

“…Multischeme transport is closely related with transport scheme adaptation [6,8], in which schemes are applied on sub-domains adaptively based on a posterior indicator. Scheme adaptation assumes that homogenization equivalence has been done on the analytical transport equation and is thus scheme-independent.…”

“…Weak forms of these interface conditions will be discussed. The interface condition for coupling SN-PN, or hybrid SN-PN has been studied in the past [1][2][3][4][5][6][7][8]. This report includes the SN-PN interface condition with upwinding that was developed in [1] for completeness and extend to the cases of all other coupling types except with LS schemes.…”