63 citations · 357 across the 53 of their papers we have counts for
55 papers
A Hyperbolic Neural Closure for M1 Radiation Transfer
Bongseok Kim, Jiahao Zhang, Johannes Krotz +3
In radiation transfer simulations, an M1 method achieves substantial computational savings by replacing the full angular transport equation with a low-order moment system. Because…
Curvilinear coordinates and curvature in radiative transport
Johannes Krotz, Ryan G. McClarren
We derive a general expression for the streaming term in radiative transport equa- tions and other transport problems when formulated in curvilinear coordinates, emphasizing coordi…
Using Deep Operators to Create Spatio-temporal Surrogates for Dynamical Systems under Uncertainty
Jichuan Tang, Patrick T. Brewick, Ryan G. McClarren +1
Spatio-temporal data, which consists of responses or measurements gathered at different times and positions, is ubiquitous across diverse applications of civil infrastructure. Whil…
Fast, Accurate Numerical Evaluation of Incomplete Planck Integrals
Whit Lewis, Ryan G. McClarren
Methods for computing the integral of the Planck blackbody function over a finite spectral range, the so-called incomplete Planck integral, are necessary to perform multigroup radi…
Collision-Based Hybrid Method for Two-Dimensional Neutron Transport Problems
Ben Whewell, Ryan G. McClarren
A collision-based hybrid method for the discrete ordinates approximation of the multigroup neutron transport equation is developed for two-dimensional time-dependent problems. At e…
Numerical Robustness of PINNs for Multiscale Transport Equations
Alexander Jesser, Kai Krycki, Ryan G. McClarren +1
We investigate the numerical solution of multiscale transport equations using Physics Informed Neural Networks (PINNs) with ReLU activation functions. Therefore, we study the analo…
A review of low-rank methods for time-dependent kinetic simulations
Lukas Einkemmer, Katharina Kormann, Jonas Kusch +2
Time-dependent kinetic models are ubiquitous in computational science and engineering. The underlying integro-differential equations in these models are high-dimensional, comprised…
The non-equilibrium Marshak wave problem in non-homogeneous media
Nitay Derei, Shmuel Balberg, Shay I. Heizler +3
We derive a family of similarity solutions to the nonlinear non-equilibrium Marshak wave problem for an inhomogeneous planar medium which is coupled to a time dependent radiation d…
A multi-fidelity adaptive dynamical low-rank based optimization algorithm for fission criticality problems
C. Scalone, L. Einkemmer, J. Kusch +1
Computing the dominant eigenvalue is important in nuclear systems as it determines the stability of the system (i.e. whether the system is sub or supercritical). Recently, the work…
A unified theory of the self-similar supersonic Marshak wave problem
Menahem Krief, Ryan G. McClarren
We present a systematic study of the similarity solutions for the Marshak wave problem, in the local thermodynamic equilibrium (LTE) diffusion approximation and in the supersonic r…
Self-similar solutions for the non-equilibrium nonlinear supersonic Marshak wave problem
Menahem Krief, Ryan G. McClarren
Similarity solutions to the nonlinear non-equilibrium Marshak wave problem with a time dependent radiation driving source are presented. The radiation transfer model used is the gr…
A Hybrid Monte Carlo, Discontinuous Galerkin method for linear kinetic transport equations
Johannes Krotz, Cory D. Hauck, Ryan G. McClarren
We present a hybrid method for time-dependent particle transport problems that combines Monte Carlo (MC) estimation with deterministic solutions based on discrete ordinates. For sp…
Uncertainty benchmarks for time-dependent transport problems
William Bennett, Ryan G. McClarren
Verification solutions for uncertainty quantification are presented for time dependent transport problems where , the scattering ratio, is uncertain. The method of polynomial ch…
Reducing Spatial Discretization Error with Linear Discontinuous Source Tilting in Iterative Quasi-Monte Carlo for Neutron Transport
Samuel Pasmann, Ilham Variansyah, C. T. Kelley +1
Recently, iterative Quasi-Monte Carlo (iQMC) was introduced as a new method of neutron transport which combines deterministic iterative methods and quasi-Monte Carlo simulation for…
iQMC: Iterative Quasi-Monte Carlo for k-Eigenvalue Neutron Transport Simulations
Samuel Pasmann, Ilham Variansyah, C. T. Kelley +1
The Iterative Quasi-Monte Carlo method, or iQMC, replaces standard quadrature techniques used in deterministic linear solvers with Quasi-Monte Carlo simulation for more accurate an…
A Collision-Based Hybrid Method for the BGK Equation
Minwoo Shin, Cory D. Hauck, Ryan G. McClarren
We apply the collision-based hybrid introduced in \cite{hauck} to the Boltzmann equation with the BGK operator and a hyperbolic scaling. An implicit treatment of the source term is…
An effective initial particle sampling technique for Monte Carlo reactor transient simulations
Ilham Variansyah, Ryan G. McClarren
We propose a technique to effectively sample initial neutron and delayed neutron precursor particles for Monte Carlo (MC) simulations of typical off-critical reactor transients. Th…
High-fidelity treatment for object movement in time-dependent Monte Carlo transport simulations
Ilham Variansyah, Ryan G. McClarren
We investigate the use of time-dependent surfaces in Monte Carlo transport simulation to accurately model prescribed, continuous object movements. The performance of the continuous…
Development of MC/DC: a performant, scalable, and portable Python-based Monte Carlo neutron transport code
Ilham Variansyah, J. P. Morgan, Jordan Northrop +2
We discuss the current development of MC/DC (Monte Carlo Dynamic Code). MC/DC is primarily designed to serve as an exploratory Python-based MC transport code. However, it seeks to…
Benchmark solutions for radiative transfer with a moving mesh and exact uncollided source treatments
William Bennett, Ryan G. McClarren
The set of benchmark solutions used in the thermal radiative transfer community suffer some coverage gaps, in particular nonlinear, non-equilibrium problems. Also, there are no non…
A Quasi-Monte Carlo Method with Krylov Linear Solvers for Multigroup Neutron Transport Simulations
Sam Pasmann, Ilham Variansyah, C. T. Kelley +1
In this work we investigate replacing standard quadrature techniques used in deterministic linear solvers with a fixed-seed Quasi-Monte Carlo calculation to obtain more accurate an…
Variable Dynamic Mode Decomposition for Estimating Time Eigenvalues in Nuclear Systems
Ethan Smith, Ilham Variansyah, Ryan McClarren
We present a new approach to calculating time eigenvalues of the neutron transport operator (also known as eigenvalues) by extending the dynamic mode decomposition (DMD) to all…
Multigroup Neutron Transport using a Collision-Based Hybrid Method
Ben Whewell, Ryan G. McClarren, Cory D. Hauck +1
A collision-based hybrid algorithm for the discrete ordinates approximation of the neutron transport equation is extended to the multigroup setting. The algorithm uses discrete ene…
A sweep-based low-rank method for the discrete ordinate transport equation
Zhuogang Peng, Ryan G. McClarren
The dynamical low-rank (DLR) approximation is an efficient technique to approximate the solution to matrix differential equations. Recently, the DLR method was applied to radiation…