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Nalu-Wind and OpenFAST: A high-fidelity modeling and simulation environment for wind energy. Milestone ECP-Q2-FY19
The goal of the ExaWind project is to enable predictive simulations of wind farms comprised of many megawatt-scale turbines situated in complex terrain. Predictive simulations will require computational fluid dynamics (CFD) simulations for which the mesh resolves the geometry of the turbines and captures the rotation and large deflections of blades. Whereas such simulations for a single turbine are arguably petascale class, multi-turbine wind farm simulations will require exascale-class resources. The primary physics codes in the ExaWind project are Nalu-Wind, which is an unstructured-grid solver for the acoustically incompressible Navier-Stokes equations, and OpenFAST, which is a whole-turbine simulation code. The Nalu-Wind model consists of the mass-continuity Poisson-type equation for pressure and a momentum equation for the velocity. For such modeling approaches, simulation times are dominated by linear-system setup and solution for the continuity and momentum systems. For the ExaWind challenge problem, the moving meshes greatly affect overall solver costs as reinitialization of matrices and recomputation of preconditioners is required at every time step. This milestone represents the culmination of several parallel development activities towards the goal of establishing a full-physics simulation capability for modeling wind turbines operating in turbulent atmospheric inflow conditions. The demonstration simulation performed in this milestone is the first step towards the "ground truth" simulation and includes the following components: neutral atmospheric boundary layer inflow conditions generated using a precursor simulation, a hybrid RANS/LES simulation of the wall-resolved turbine geometry, hybridization of the turbulence equations using a blending function approach to transition from the atmospheric scales to the blade boundary layer scales near the turbine, fluid-structure interaction (FSI) that accounts for the complete set of blade deformations (bending, twisting and pitch motion, yaw and tower displacements) by coupling to a comprehensive turbine dynamics code (OpenFAST). The use of overset mesh methodology for the simulations in this milestone presents a significant deviation from the previous efforts where a sliding mesh approach was employed to model the rotation of the turbine blades. The choice of overset meshes was motivated by the need to handle arbitrarily large deformations of the blade and to allow for blade pitching in the presence of a controller and the ease of mesh generation compared to the sliding mesh approach. FSI and the new timestep algorithm used in the simulations were developed in partnership with the A2e High-Fidelity Modeling project. The individual physics components were verified and validated (V%V) through extensive code-to-code comparisons and with experiments where possible. The detailed V&V efforts provide confidence in the final simulation where these physics models were combined together even though no detailed experimental data is available to perform validation of the final configuration. Taken together, this milestone successfully demonstrated the most advanced simulation to date that has been performed with Nalu-Wind.
ECP Final Design Report - VTK-m Contribution (WBS 2.3.4.13)
An short overview, status, and accomplishments of the VTK-m contribution are provided.
FY19Q2 report for ATDM AD projects to ECP
Performance to Plan highlights are provided.
ECP External Review - Sandia National Laboratories ATDM (WBS X.X.X.X)(KPP-2)
Accomplishments to date are provided for several programs: SPARC for Virtual Flight Testing; EMPIRE for Electromagnetic Plasma Physics; and the Science Challenge Problem Description.
ATDM ST Projects to ECP (Q3 FY2019 Report)
Accomplishments and progress are reported for quarter 3, FY2019.
ATDM AD projects to ECP (Q3 FY2019 Report)
The four key emission models necessary for B-dot cavity physics and DSMC (Direct Simulation Monte Carlo) collision models for Argon background gas have been implemented and tested. A series of B-dot simulations have been performed with vacuum, gas fill, and gas fill with space-charge limited emission models. Results are being validated against NIF experimental data. These were presented at the mid-term panel review. The ATS-1 L2 milestone is dependent on this milestone and is similarly on track. The mid-term review occurred at SNL on 5/15/2019. Target problems at the requisite scale and of interest to this Milestone have been defined and will be run during Q4.
Towards Use of Mixed Precision in ECP Math Libraries
The use of multiple types of precision in mathematical software has the potential to increase its performance on new heterogeneous architectures. The xSDK project focuses both on the investigation and development of multiprecision algorithms as well as their inclusion into xSDK member libraries. This report summarizes current efforts on including and/or using mixed precision capabilities in the math libraries Ginkgo, heFFTe, hypre, MAGMA, PETSc/TAO, SLATE, SuperLU, and Trilinos, including KokkosKernels. It contains both numerical results from libraries that already provide mixed precision capabilities, as well as descriptions of the strategies to incorporate multiprecision into established libraries.
ECP Milestone Memo WBS 2.3.4.13 ECP/VTK-m FY19Q3 [MS-19/08] Point Movement STDA05-19
The milestone tasks and completion proofs are provided.
ATDM AD projects to ECP Report (Q3 FY2020)
The SPARC team has completed much of the workflow development needed for the coupled and uncoupled analyses needed to support our flight test validation work. The SPARC team has continued to make progress on development activities to support unsteady, full reentry vehicle aero analysis, which have focused on turbulence modeling, uniform mesh refinement, in-situ visualization (with the Paraview/Catalyst team), and performance analysis. The SPARC team is making solid progress towards our Q4 goal of demonstrating an improved Wall Modeled Large Eddy Simulation (WMLES) capability for standard geometries using high-order finite difference, discontinuous Galerkin, and low-dissipation finite volume methods. The SPARC team has met the minimum completion criteria for parts of the L1, including documenting performance and scaling of SPARC on Trinity, Sierra and Astra, and performing runs for the flight test validation case.
Why We Need Strategies for Working Remotely: the Exascale Computing Project (ECP) Panel Series.
Abstract not provided.
ExaLearn – GenTen Tensor Software ECP Milestone
The objective of this milestone was to finish integrating GenTen tensor software with combustion application Pele using the Ascent in situ analysis software, partnering with the ALPINE and Pele teams. Also, to demonstrate the usage of the tensor analysis as part of a combustion simulation.
MTT maintenance/deployment on ECP platforms [Poster]
Abstract not provided.