Emerging Technologies for FETCH2 Jeff Gomes Applied Modelling and Computation Group (AMCG) Severe Accident Subproject Meeting 14/11/2011

Outline  Multi-Physics Software Suite;  Next-Generation Multiphase Flow Dynamic core (synergy between projects within AMCG);  Emerging Multi-Physics Technologies.

AMCG: Multi-Physics Software Suite Fluidity (Multiphase) EVENT (Radiation Transpot) FETCH (coupled Multiphase and RT) Fluidity-ICOM (CFD, single phase, multi-material) Fluidity-Multiphase (CMFD) VGeST (DEM, FEMDEM) Radiant (RT) FETCH-2 (couples multiphase, RT and structural response) Legacy Fissile solutions, porous media matrix, reactors; Compressible (with phase change) and incompressible flows; Simple structural mechanics response (i.e., limited stress failure criteria); Quad/Hex finite elements with CV representation of scalar fields (no parallel adaptivity); Add an adaptivity library which performs topological operations on the mesh, and mesh movement, to optimise the size and shape of elements in response to error measures Working robustly and efficiently in parallel Also building an adjoint to the model for data assimilation, sensitivity studies and goal-based error estimation Make use of open source solutions for solvers, preconditioners, I/O, visualisation, etc Multi-Physics Models Finite/Discrete Element Methods; Particle modelling (Newton Law) and structural mechanics (material engineering – stress modelling); One-/Two-Way coupling with Fluidity; Used in coastal defence, reservoir fractures and particle flows applications; But can be potentially used in nuclear engineering (geological waste repository and stress-induced core fractures and degradation in reactors)

Page 4 AMCG: Multi-Physics Software Suite

Research & Development: Emerging Technologies (Improving Modelling Functionality)

R&D (Cross-Cutting activities), AMCG New Dynamic Core for multiphase flow in Fluidity FP7/THINS: Discretisation Methods FP7/GoFastR & EPSRC-SA: Safety Assessment in reactors (severe accident scenarios) EPSRC- MBase/B&W: Criticality in Fissile Solutions Qatar Petroleum/Shell New Model for Reservoir Simulator FETCH2

Lower frame shows the domain decomposition which has been optimised to balance the load based on number of nodes and minimised edge cut Emerging Technologies: Mesh Adaptivity and Domain Decomposition

Page 8 Movie Emerging Technologies: Mesh Adaptivity and Domain Decomposition – lock-exchange problem (P1DGP2 balance element)

Compressible high-resolution control volume advection methods combined with moving and adaptive meshes; Limiting schemes to ensure conservative and bounded solutions; Arbitrary number of materials can be tracked. Emerging Technologies: Multi-Material Interface Tracking (moving and adaptative meshes)

Emerging Technologies: Multi-Material Interface Tracking (3 materials)

Page 11 ‘donor’ mesh ‘target’ mesh ‘super mesh’ and mapping from donor mesh Following construction of the supermesh we are able to perform projection operations to achieve conservative, bounded (etc…) interpolation schemes. 2D: Farrell et al., D: Farrell, Maddison, 2009 Emerging Technologies: Conservative interpolation – crucial for many applications with mesh adaptivity and coupled models

FEM Emerging Technologies: Finite/Discrete Element Methods (FEMDEM) DEM+

Emerging Technologies: Finite/Discrete Element Methods (FEMDEM) Land-slide and Idealised coastal defence

Emerging Technologies: Finite/Discrete Element Methods (FEMDEM) Idealised coastal defence accropode blocks; Study of stress-induced fractures for different block designs.

 One-/Two-way coupling of Fluids and Solids (Capturing Interactions)  In Fluidity, solid is treated as fluid (multiphase flow)  1 mesh for the domain (fluid), 1 mesh for solid: user-friendly as it is easy to generate the meshes of complex solids  Usage of Conservative Interpolation in order to obtain solid's location on the fluids mesh  Exchange of momentum and location between solids and fluid at each time-step  Introducing third phase: Air (acting as a surface) Emerging Technologies: Immersed-Body Method (Fluid-Solid Interaction Modelling)

Re=5k Re=1k Immersed- Body Method

Emerging Technologies: Immersed-Body Method (Fluid-Solid Interaction Modelling)

Emerging Technologies: Thermo-Chemical Modelling Initial generic chemical modelling framework for geochemistry application (funded by QCCRSC Programme) for oil/gas reservoirs, CO 2 sequestration and storage aquifers (PhD student); Chemical kinetics and thermodynamic equilibrium; In order to improve of our understanding of a set of SA phenomenology we need a sophisticated thermo- chemical model framework within (or coupled to) FETCH2 with a reliable chemical-kinetics library covering: Chemical reactions and advanced thermodynamics (EOS  phase change);

Back-up Slides

 Code repository;  Automatic and continuous verification & validation;  More than 100 verification & validation test-cases for RT;  More than 1000 verification & validation test-cases for CFD (including unit-tests);  Large number of benchmark tests for the coupled formulation (e.g., TRACY, SILENE, CRAC, SUPO, HTR, Shipping-port reactor and other AIEA –based tests)  Full documentation;  International training (e.g., B&W, LANL, Y12, open-source community, etc) Research & Development Model and Software Quality Assurance

Research & Development Model and Software Quality Assurance