Vertical structure and physical processes of the Madden‐Julian oscillation: Linking hindcast fidelity to simulated diabatic heating and moistening
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Nicholas P. Klingaman↗
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Results for “simulation fidelity”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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High Fidelity 3D Simulations of Discharge in Helium/Nitrogen Including Photonic Effects.
Abstract not provided.
Moore, Christopher Hudson↗
AI Deep Learning Tool for High-Fidelity Physics Simulations of Nuclear Reactor Systems
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22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Toward High Fidelity LES Simulations of 5 x 5 PWR Fuel Bundle with Mixing Vane
The present work illustrates one example of a computational fluid dynamics (CFD) application in the nuclear engineering field. Since CFD is one of the most powerful tools available at the actual state of the art that could in principle help and assist the design process, a compromise should be established between the accuracy of the CFD numerical model (RANS - LES - DNS) and the computational cost of the simulations. In this spirit, this work will present the computational results from two different CFD model categories, Large Eddy Simulations (LES) and Reynolds-averaged Navier-Stokes (RANS) models. Both treat the flow turbulence issue in two separate ways, which differ mostly in the resolution of the turbulence statistics and the computational cost. The single-phase hydraulic problem presented involves the steady-state turbulent flow field modelling and resolution around a scaled PWR mixing vane grid, designed by Westinghouse and tested by Texas A and M University. The role of the mixing vane/spacer grid is to enhance the turbulent mixing and hence heat transfer of the core coolant around fuel bundles, thus increasing the departure of nucleate boiling-critical heat flux (DNB-CHF) point, as well as important structural functions for the rods bundles. The authors numerically studied the flow field characteristics at the region downstream of the spacer grids and validated their results to particle imagery velocimetry (PIV) measurements. Dominguez and Hassan performed two-dimensional time resolved PIV (TR-PIV) measurements within a 5 x 5 PWR rod bundle with spacer-grids that utilized a matching index of refraction (MIR) approach. Their averaged data showed a rather uniform direction velocity profile after the spacer grid while the downstream illustrated a no slip wall profile. The available PIV flow field experimental results from Texas A and M show complex structures of the flow field downstream the mixing vanes with the formation of secondary flows that tend to enhance the turbulent heat transfer, due to the mixing vanes geometry itself. Computational results will be validated with the available experimental data.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Kinetic Plasma Simulation Capabilities in the MOOSE Framework: Verification of Particle-Particle Collisions
High-fidelity simulations of complex plasma systems allow researchers to gain key insights into and understanding of these systems. To facilitate massively parallel high-fidelity plasma simulations, finite-element-based particle-in-cell capabilities are being developed within the open-source Multiphysics Object-Oriented Simulation Environment (MOOSE) based framework called Software for Advanced Large-scale Analysis of MAgnetic confinement for Numerical Design, Engineering & Research (SALAMANDER). While SALAMANDER’s primary objective is modeling edge plasmas and plasma-facing components in fusion devices, the particle-in-cell capabilities being developed are general and will support modeling low-temperature plasmas as well. Previously, collisionless magnetostatic simulation capabilities have been verified with the two-stream and Dorey-Guest-Harris instabilities, and single particle motion. Collisions were implemented using the direct simulation Monte Carlo method, and verification of this capability will be presented here several verification problems: relaxation of a randomly initialized gas to a Maxwellian distribution, Fourier heat flow, and comparison of reaction rates to both analytic calculations and those calculated using a multi-term Boltzmann solver.
70 - PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Rotorcraft Research at the NASA Vertical Motion Simulator
In the 1970 s the role of the military helicopter evolved to encompass more demanding missions including low-level nap-of-the-earth flight and operation in severely degraded visual environments. The Vertical Motion Simulator (VMS) at the NASA Ames Research Center was built to provide a high-fidelity simulation capability to research new rotorcraft concepts and technologies that could satisfy these mission requirements. The VMS combines a high-fidelity large amplitude motion system with an adaptable simulation environment including interchangeable and configurable cockpits. In almost 30 years of operation, rotorcraft research on the VMS has contributed significantly to the knowledge-base on rotorcraft performance, handling qualities, flight control, and guidance and displays. These contributions have directly benefited current rotorcraft programs and flight safety. The high fidelity motion system in the VMS was also used to research simulation fidelity. This research provided a fundamental understanding of pilot cueing modalities and their effect on simulation fidelity.
Aponso, Bimal Lalith↗
Application of the Most Likely Extreme Response Method for Wave Energy Converters: Preprint
Extreme loads are often a key cost driver for wave energy converters (WECs). As an alternative to exhaustive Monte Carlo or long-term simulations, the most likely extreme response (MLER) method allows mid- and high-fidelity simulations to be used more efficiently in evaluating WEC response to events at the edges of the design envelope, and is therefore applicable to system design analysis. The study discussed in this paper applies the MLER method to investigate the maximum heave, pitch, and surge force of a point absorber WEC. Most likely extreme waves were obtained from a set of wave statistics data based on spectral analysis and the response amplitude operators (RAOs) of the floating body; the RAOs were computed from a simple radiation-and-diffraction-theory-based numerical model. A weakly nonlinear numerical method and a computational fluid dynamics (CFD) method were then applied to compute the short-term response to the MLER wave. Effects of nonlinear wave and floating body interaction on the WEC under the anticipated 100-year waves were examined by comparing the results from the linearly superimposed RAOs, the weakly nonlinear model, and CFD simulations. Overall, the MLER method was successfully applied. In particular, when coupled to a high-fidelity CFD analysis, the nonlinear fluid dynamics can be readily captured.
16 TIDAL AND WAVE POWER↗
Development of a High-Fidelity CLARREO Pathfinder Simulator
CLARREO Pathfinder is a hyperspectral instrument designed to resolve reflectance of solar radiation from Earth in the wavelength range of 350 nm to 2300 nm with an uncertainty of 0.3% (k=2) or less. Its success will demonstrate CLARREO’s ability to provide on-orbit SI-Traceable calibration of measured spectral reflectance with an advanced accuracy. The CLARREO pathfinder simulator has been developed to generate high-fidelity inter-calibration event data products that can be used for pre-launch inter-calibration algorithm study. A high-fidelity simulation for CLARREO inter-calibration events includes computationally intensive radiative transfer calculations for observations within each individual collocation footprint. A principal component based radiative transfer model is incorporated in the simulator to enable an ultra-fast forward simulation, ensuring a low latency data processing for month- to year-long intercalibration events. This paper introduces the design and development of the CLARREO pathfinder simulator and some of its applications for inter-calibration matching error evaluation.
Wan Wu↗
White paper on plasma simulation
Increases in computer power combined with improved algorithms have considerably improved the ability of simulations to model plasma experiments. Higher fidelity simulations with more complete physics treatment and better resolution have improved our understanding of the physics controlling the performance of these experiments. For example, in inertial confinement fusion (ICF) simulations of indirect drive ignition targets and capsules can now include the broad range of perturbation sources, including surface imperfections, engineering features and drive asymmetries together in a fully 3D geometry. These have significantly improved the ability of simulations to match a suite of experimental observations across a range of targets.1-3 Simulations of direct drive targets and magnetically driven targets have also increased in fidelity and realism. The US is the leader in its capabilities to perform plasma simulations. This leadership has highly important implications for national security as well as future energy security and economic competitiveness.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Testing the Exploration Conops (Excon) Mockup Suit in Lunar Analog Environments in 2022
Understanding how to effectively train for Extravehicular Activities (EVAs) for Artemis missions is critical. Developing high-fidelity simulation environments is important for Artemis mission preparation. Because the actual Lunar exploration environment cannot be fully replicated on Earth, it is paramount to determine where and how to properly train the Artemis team. Tasked by the new Extravehicular Activity and Human Surface Mobility Program(EHP), a team of stakeholders from engineering, flight operations, human health and performance, astromaterials and science, and the crew office worked together to perform EVAs in 3 simulated lunar environments. The overall focus for this test series was developing the capability to perform Artemis simulated EVAs in high-fidelity, full-scale environments. This test series was broken into 3 distinct tests titled after the EHP integrated test team: Joint EVA Test Team (JETT). The test locations are planned to serve as Artemis training sites and were selected because of their relevance to the expected Artemis Lunar terrain. JETT1was conducted near Kilbourne Holeby El Paso, Texas and focused on hardware development and checkout. JETT2 was conducted in the Icelandic Highlands and began the transition towards EVA concept operations(con-ops), risks and technology.JETT3 was conducted near SP Crater by Flagstaff Arizona and focused on simulating the Artemis III mission with a simulated Houston based Flight Control Team (FCT) and a Science Mission Directorate (SMD) science team. All three JETT tests utilized the Excon mockup space suit. The Excon mockup suit is a light-weight, unpressurized Exploration Extravehicular Mobility Unit (xEMU)simulator. While it cannot replicate the feel of working within a pressurized suit, it does introduce similar volume constraints and some of the mobility programing to simulate the user experience in the xEMU. Overall, the JETT testing was able to create a simulated Lunar EVA and have two subjects perform full scale operations in line with Artemis III mission expectations. Future work is planned to continue to improve the simulation quality of Lunar EVA simulations.
spacesuit↗
Testing the Exploration ConOps (ExCon) Mockup Suit in Lunar Analog Environments in 2022
Understanding how to effectively train for Extravehicular Activities (EVAs) for Artemis missions is critical. Developing high-fidelity simulation environments is important for Artemis mission preparation. Because the actual Lunar exploration environment cannot be fully replicated on Earth, it is paramount to determine where and how to properly train the Artemis team. The overall focus for this test series was developing the capability to perform Artemis simulated EVAs in high-fidelity, full-scale environments. This test series was broken into three distinct tests titled after the EVA & Human Surface Mobility (HSM) Program (EHP) integrated test team: Joint EVA & HSM Test Team (JETT). The test locations are planned to serve as Artemis training sites and were selected because of their relevance to the expected Artemis Lunar terrain. JETT1 was conducted near Kilbourne Hole by El Paso, Texas and focused on hardware development and checkout. JETT2 was conducted in the Icelandic Highlands and began the transition towards EVA concept of operations (con-ops), risks and technology. JETT3 was conducted near SP Crater by Flagstaff, Arizona and focused on simulating the Artemis III mission including a Houston based Flight Control Team (FCT) and a Science Mission Directorate (SMD) science team. All three JETT tests utilized the Exploration Concept of Operations (ExCon) mockup space suit. The ExCon mockup suit is a lightweight, unpressurized Exploration Extravehicular Mobility Unit (xEMU) simulator. While it cannot replicate the feel of working within a pressurized suit, it does introduce similar volume constraints and some of the mobility programing to simulate the user experience in the xEMU. Overall, the JETT testing was able to create a simulated Lunar EVA and have two subjects perform full scale operations in line with Artemis III mission expectations. Future work is planned to continue to improve the simulation quality of Lunar EVA simulations.
spacesuit↗
Testing the Exploration Conops (Excon) Mockup Suit in Lunar Analog Environments in 2022
Understanding how to effectively train for Extravehicular Activities (EVAs) for Artemis missions is critical. Developing high-fidelity simulation environments is important for Artemis mission preparation. Because the actual Lunar exploration environment cannot be fully replicated on Earth, it is paramount to determine where and how to properly train the Artemis team. The overall focus for this test series was developing the capability to perform Artemis simulated EVAs in high-fidelity, full-scale environments. This test series was broken into three distinct tests titled after the EVA & Human Surface Mobility (HSM) Program (EHP) integrated test team: Joint EVA & HSM Test Team (JETT). The test locations are planned to serve as Artemis training sites and were selected because of their relevance to the expected Artemis Lunar terrain. JETT1 was conducted near Kilbourne Hole by El Paso, Texas and focused on hardware development and checkout. JETT2 was conducted in the Icelandic Highlands and began the transition towards EVA concept of operations (con-ops), risks and technology. JETT3 was conducted near SP Crater by Flagstaff, Arizona and focused on simulating the Artemis III mission including a Houston based Flight Control Team (FCT) and a Science Mission Directorate (SMD) science team. All three JETT tests utilized the Exploration Concept of Operations (ExCon) mockup space suit. The ExCon mockup suit is a lightweight, unpressurized Exploration Extravehicular Mobility Unit (xEMU) simulator. While it cannot replicate the feel of working within a pressurized suit, it does introduce similar volume constraints and some of the mobility programing to simulate the user experience in the xEMU. Overall, the JETT testing was able to create a simulated Lunar EVA and have two subjects perform full scale operations in line with Artemis III mission expectations. Future work is planned to continue to improve the simulation quality of Lunar EVA simulations.
spacesuit↗
Integrated Tokamak modeling: When physics informs engineering and research planning
Modeling tokamaks enables a deeper understanding of how to run and control our experiments and how to design stable and reliable reactors. We model tokamaks to understand the nonlinear dynamics of plasmas embedded in magnetic fields and contained by finite size, conducting structures, and the interplay between turbulence, magneto-hydrodynamic instabilities, and wave propagation. This tutorial guides through the components of a tokamak simulator, highlighting how high-fidelity simulations can guide the development of reduced models that can be used to understand how the dynamics at a small scale and short time scales affects macroscopic transport and global stability of plasmas. It discusses the important role that reduced models have in the modeling of an entire plasma discharge from startup to termination, the limits of these models, and how they can be improved. It discusses the important role that efficient workflows have in the coupling between codes, in the validation of models against experiments and in the verification of theoretical models. Finally, it reviews the status of integrated modeling and addresses the gaps and needs towards predictions of future devices and fusion reactors.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Flight simulation - A vital and expanding technology in aircraft development
Flight simulation, both ground and in-flight, is experiencing major technological improvement and growth. The increased capabilities are providing new opportunities for support of the aircraft development process. The development of faster digital computers, improved visual displays, better motion systems and increased interest in simulation fidelity has improved the ground simulator to the point where it accomplishes a major portion of the aircraft development before work on the flight article begins. The efficiency of the ground simulator as a forecaster for the flight testing phase is becoming well established. In-flight simulation is properly being used to bridge the gap between the ground simulator and the flight test article. Simulation provides the vital link between analysis, aerodynamic tests, and subsystem tests and the flight test article. This paper describes the latest advances in flight simulation and its increasing role in the aircraft development process.
Reynolds, P. A.↗
3D modeling of the Staged Z-pinch with the FLASH code
The Staged Z-pinch (SZP) fusion concept is a magneto-inertial compression scheme developed by Magneto-Inertial Fusion Technologies, Inc. (MIFTI), in which small amounts of fusion fuel are brought to fusion-relevant conditions by passing multi-million amperes strong current through a cylindrical shell of high atomic number material. One- and two-dimensional modeling performed by MIFTI with the MACH2 code, suggests that net fusion energy gain can be achieved when currents in the 10 million amperes range compress a 50%-50% mixture of deuterium and tritium gas. In this project we enhance and use the FLASH code to execute high-fidelity, simulations of various SZP configurations, a collaboration between the Flash Center for Computational Science at the University of Rochester and the Laboratory for Laser Energetics, and MIFTI. FLASH is a high-performance computing, multi-physics, radiation magnetohydrodynamic (MHD) code with extended physics capabilities, which is developed at the Flash Center. The goal of this project is to assess the shell/fuel stability of the pinch to two- and three-dimensional MHD instabilities and to utilize FLASH’s extended physics capabilities to understand how extended-MHD effects impact implosion dynamics and plasma conditions at stagnation. The project is a natural extension of an ongoing collaborative effort between MIFTI and the Flash Center through the U.S. DOE Advanced Research Projects Agency-Energy (ARPA-E) BETHE program and can provide MIFTI with simulation capabilities that are currently beyond their reach with MACH2. Ultimately, MIFTI wants FLASH to become one of their simulation workhorses for reliable, high-fidelity SZP platform design. During the project, the Flash Center team developed a suite of in one- and two-dimensional FLASH simulations to model different variants of the SZP platform, performed code-to-code comparisons with MACH2, and used the FLASH code to design and model SZP experiments like the Double Eagle experiments that MIFTI recently performed. Also, the Flash Center team developed the capabilities of FLASH to be able to do three-dimensional simulations of pulsed-power experiments with the code for the first time. Two publications from this effort are currently under review and two more are in preparation. MIFTI has also committed to the use of FLASH for future SZP simulation efforts.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Quantum Simulation of Polarized Light-Induced Electron Transfer with a Trapped-Ion Qutrit System
Electron transfer within and between molecules is crucial in chemistry, biochemistry, and energy science. Here this study describes a quantum simulation method that explores the influence of light polarization on electron transfer between two molecules. By implementing precise and coherent control among the quantum states of trapped atomic ions, we can induce quantum dynamics that mimic the electron-transfer dynamics in molecules. We use three-level systems (qutrits), rather than traditional two-level systems (qubits), to enhance the simulation efficiency and realize high-fidelity simulations of electron-transfer dynamics. We treat the quantum interference between the electron coupling pathways from a donor with two degenerate excited states to an acceptor and analyze the transfer efficiency. We also examine the potential error sources that enter the quantum simulations. The trapped-ion systems have favorable scalings with system size compared to those of classical computers, promising access to richer electron-transfer simulations.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
A study of the characteristics and the simulation of the planetary radiation environment
Characteristics of radiant flux in vicinity of earth, method for simulating distribution of flux, and effect of approximations on simulation fidelity
SIMULATION↗