Timothy Michael Wildey

Adjoint Based a posteriori Error Estimation in Drekar::CFD

This document summarizes the results from a level 3 milestone study within the CASL VUQ effort. It demonstrates the capability to perform adjoint-based a posteriori error estimation within Drekar::CFD. The a posteriori error estimates require the solution of a (linear) adjoint problem in a higher order approximation space with data chosen based on the quantity of interest. The a posteriori error estimates are verified using an analytical solution to a laminar flow problem. Finally, the framework is demonstrated on the TH-M Test Case #2 involving a 3-dimensional axisymmetric sudden expansion with a moderate Reynolds numbers ( 5000).

Thermal hydraulic simulations, error estimation and parameter sensitivity studies in Drekar::CFD

This report describes work directed towards completion of the Thermal Hydraulics Methods (THM) CFD Level 3 Milestone THM.CFD.P7.05 for the Consortium for Advanced Simulation of Light Water Reactors (CASL) Nuclear Hub effort. The focus of this milestone was to demonstrate the thermal hydraulics and adjoint based error estimation and parameter sensitivity capabilities in the CFD code called Drekar::CFD. This milestone builds upon the capabilities demonstrated in three earlier milestones; THM.CFD.P4.02 [12], completed March, 31, 2012, THM.CFD.P5.01 [15] completed June 30, 2012 and THM.CFD.P5.01 [11] completed on October 31, 2012.

A comparison of adjoint and data-centric verification techniques.

This document summarizes the results from a level 3 milestone study within the CASL VUQ effort. We compare the adjoint-based a posteriori error estimation approach with a recent variant of a data-centric verification technique. We provide a brief overview of each technique and then we discuss their relative advantages and disadvantages. We use Drekar::CFD to produce numerical results for steady-state Navier Stokes and SARANS approximations. 3