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Filtering by: Has journal Discrete and Continuous Dynamical Systems Remove constraint Has journal: Discrete and Continuous Dynamical Systems Advisor Palmer, Todd S. Remove constraint Advisor: Palmer, Todd S.

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  • Extending the discrete maximum principle for the IMC equations

    Creator:
    Talbot, Paul W.
    Abstract:
    The implicit Monte Carlo (IMC) method [16] for radiative transfer, developed in 1971, provides numerical solutions to the tightly-coupled, highly-nonlinear radiative heat transfer equations in many physical situations. Despite its popularity, there are instances of overheating in the solution for particular choices of time steps and spatial grid sizes. To...
    Resource Type:
    Masters Thesis
    Full Text:
    discretized in steps, and implicit differencing is often used to approx­ imate continuous time. While

  • Discrete Ordinates Radiation Transport using High-Order Finite Element Spatial Discretizations on Meshes with Curved Surfaces

    Creator:
    Woods, Douglas N.
    Abstract:
    We spatially discretize the Sn transport equation using the high-order (HO) discontinuous finite element method (DFEM) on HO meshes. Previous work provided a proof-of-concept for this spatial discretization method in X-Y geometry. Included in the present work, we derive a spatial discretization for the Sn transport equation in both X-Y...
    Resource Type:
    Dissertation
    Full Text:
    many physical systems. A few examples are nuclear reactors [3], medical radiation treatments [4], and

  • Advanced Deterministic Phonon Transport Techniques for Predicting Spectral Thermal Conductivity in Homogeneous and Heterogeneous Media

    Creator:
    Harter, Jackson R.
    Abstract:
    We present a deterministic spectral method to predict equilibrium temperature distributions, heat flux, and thermal conductivity in homogeneous and heterogeneous media. We solve the Boltzmann transport equation in a second order spatial, self-adjoint angular flux formulation. We implemented this method into the radiation transport code Rattlesnake, built using the MOOSE...
    Resource Type:
    Dissertation
    Full Text:
    continuous finite element method with unstructured meshes, and the angular variable is discretized with the

  • Accelerated Deterministic Phonon Transport in Lithium Aluminate with Interfacial Scattering Treatment

    Creator:
    Whitman, Nicholas H.
    Abstract:
    We present a method for deterministically solving the consistent temperature and frequency dependent phonon radiative transport problem. We use the single relaxation time (SRT) approximation in the Self-Adjoint Angular Flux (SAAF) form with discrete ordinates (S_N) angular discretization method and continuous finite element method (CFEM) for spatial discretization. Included are...
    Resource Type:
    Dissertation
    Full Text:
    discretized using the continuous finite element method and angu- larly discretized using the discrete

  • Diffusion Accelerated Implicit Monte Carlo via Nonlinear Elimination for Thermal Radiative Transfer

    Creator:
    Lam, Adam Q.
    Abstract:
    In this dissertation, we derive and implement a new transport-diffusion hybrid algorithm for solving thermal radiative transfer (TRT) problems. Using the method of nonlinear elimination (NLEM), the TRT system of equations can be written in terms of a transport equation with the absence of scattering and a diffusion equation. The...
    Resource Type:
    Dissertation
    Full Text:
    Carlo transport solver and a linear- continuous discretization for the diffusion equation. For problems

  • Coarse mesh and one-cell block inversion based diffusion synthetic acceleration

    Creator:
    Kim, Kang-Seog
    Abstract:
    DSA (Diffusion Synthetic Acceleration) has been developed to accelerate the SN transport iteration. We have developed solution techniques for the diffusion equations of FLBLD (Fully Lumped Bilinear Discontinuous), SCB (Simple Corner Balance) and UCB (Upstream Corner Balance) modified 4-step DSA in x-y geometry. Our first multi-level method includes a block...
    Resource Type:
    Dissertation
    Full Text:
    continuous diffusion equation derived from the asymptotic analysis, and avoids void cell calculation. We

  • A General Purpose Agent-Based Blackboard Optimization Method Applied to Sodium Fast Reactor Design and Analysis

    Creator:
    Stewart, Ryan H.
    Abstract:
    We present a novel multi-objective optimization methodology built upon a multi-agent blackboard framework. This multi-agent blackboard system (MABS) synthesizes blackboard architectures, multi-agent environments, and optimization theory. The blackboard architecture creates the framework for initializing, storing, and solving a multi-objective optimization problem. Multiple agents allow for an optimization problem to be...
    Resource Type:
    Dissertation
    Full Text:
    continuous or discrete and are used to create a unique design. Each design is used to determine the values

  • An Exploration of Used Fuel Sharing in Multi-Reactor Power Plants

    Creator:
    Lilley, Benjamin C.
    Abstract:
    Nuclear fuel management is an optimization problem on many levels. Finding “viable” solutions for the core reload design problem is difficult without expert knowledge and software automation. Small modular reactors with a shared used fuel pool demonstrate a novel opportunity for fuel cycle optimization. A Python package was developed and...
    Resource Type:
    Dissertation
    Full Text:
    used to search the core reload design space for a two-reactor system, with and without used fuel

  • Investigation of the IRWST flow patterns during a simulated station blackout experiment on the OSU APEX facility

    Creator:
    Strohecker, Mark F.
    Abstract:
    The OSU/APEX thermal hydraulic test facility models the passive safety systems of the Westinghouse AP600 advanced light water reactor design. Numerous experiments have been performed to test these systems, the one of focus here is the station blackout scenario. This experiment simulated the complete loss of AC power to all...
    Resource Type:
    Masters Thesis
    Full Text:
    system, the passive safety systems, and parts of the non-safety grade chemical and volume control

  • Reduced Order Modeling of Radiation Diffusion Kinetics via Proper Generalized Decomposition

    Creator:
    Alberti, Anthony L.
    Abstract:
    In this dissertation, we attempt to overcome the "curse of dimensionality" inherent to radiation diffusion kinetics problems by employing a novel reduced order modeling technique known as proper generalized decomposition (PGD). After verifying a proposed PGD algorithm and associated solvers through various tests, we explore its performance for computing reduced-order...
    Resource Type:
    Dissertation
    Full Text:
    Systems of Equations and PGD Algorithms for Neutron Diffusion Kinetics