Mitigating the ray effect in radiative transport equation simulations

by Prof. Min Tang

Tuesday May 27, 2025, 11:15 AM → 12:15 PM Europe/Paris

Amphi Schwartz (IMT)

The Discrete Ordinates Method (DOM) is the most widely used
velocity discretization method for simulating the radiative transport
equation. However, the ray effect is a long-standing drawback of DOM. In
benchmark tests that exhibit the ray effect, we observe low regularity in
the velocity variable of the solution. To address this issue, we introduce
randomness into the velocity discretization and propose two methods: the
Random Ordinate Method and Random Source Iteration, to mitigate the ray
effect. Compared to other strategies proposed in the literature for
mitigating the ray effect, these two methods offer several advantages:1 )
the computational cost is comparable to that of DOM; 2) they are simple and
require minimal changes to existing codes; 3) they are easily parallelizable
and independent of the problem setup. Numerical tests demonstrate the
reduction in computational cost compared to classical methods, as well as
their effectiveness in mitigating the ray effect.