A5077924445- Gas Dynamics and Kinetic Theory
- Planetary Science and Exploration
- Astro and Planetary Science
- Computational Fluid Dynamics and Aerodynamics
- Spacecraft and Cryogenic Technologies
- Probabilistic and Robust Engineering Design
- Diamond and Carbon-based Materials Research
- Particle Dynamics in Fluid Flows
- Granular flow and fluidized beds
- Landslides and related hazards
- Fluid Dynamics and Turbulent Flows
- High-pressure geophysics and materials
- Rocket and propulsion systems research
- Nuclear Engineering Thermal-Hydraulics
- Tunneling and Rock Mechanics
- Vehicle emissions and performance
- Space Satellite Systems and Control
- Surface Roughness and Optical Measurements
- Electrohydrodynamics and Fluid Dynamics
- Heat Transfer Mechanisms
- Semiconductor materials and devices
- Optical Polarization and Ellipsometry
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- Fluid Dynamics and Heat Transfer
Marshall Space Flight Center
2021-2024
CFD Research Corporation (United States)
2021-2024
Jacobs (United States)
2021-2022
GeoCento (United Kingdom)
2022
University of Michigan
2016-2017
Purdue University West Lafayette
2010-2016
Goddard Space Flight Center
2012
Vantage View (United States)
2012
Radiant Research (United States)
1991
Chalmers University of Technology
1977
Revised parameters for variable soft sphere (VSS) and Lennard-Jones (L-J) (6-12) models are presented eight common gases in the temperature range 20–2200 K. The new based on a critical review of experimental measurements ab-initio calculations shear viscosity self-diffusion coefficients. optimized assessed relative to thermal conductivity. Results indicate most significant improvements VSS model occur when considering lighter where repulsive forces more important. agreement with transport...
View Video Presentation: https://doi.org/10.2514/6.2022-1808.vid Rocket plume-surface interaction is a multi-phase, complex discipline characterized by plume flow physics, erosion and ejecta dynamics. To provide critical data for the validation of predictive modeling capabilities, an inert-gas, subscale ground test has been designed, with one phase focused on cratering another structure behavior. Using supersonic, heated N2 jet impinging onto six different mechanical regolith simulants,...
ABSTRACT A number of studies have been carried out by other researchers into cleaning deviated holes. However, the results to date do not provide clear operational recommendations. research programme that addresses hole is in progress using Field-scale equipment. Experimental obtained from circulating water and HEC polymer-based pills. The experimental are complemented mathematical modelling. comparison inclined equipment show only transport cuttings initiated at lower flow rates when...
The Gravity and Extreme Magnetism Small Explorer (GEMS) will realize its scientific objectives through high sensitivity linear X-ray polarization measurements in the 2-10 keV band. GEMS polarimeters, based on photoelectric effect, provide a strong response with quantum efficiency over broad band-pass by novel implementation of time projection chamber (TPC). This paper discuss basic principles TPC polarimeter describe details mechanical electrical design flight polarimeter. We present...
Uncertainty quantification in the hypersonic flow regime offers valuable information to determine physical models need of improvement and assist design vehicles flight experiments. Here we present results uncertainty analysis based on polynomial chaos method flowfield surface heat flux under typical blunt-body reentry conditions. The NASA Langley Aerothermodynamic Upwind Relaxation Algorithm code [Cheatwood, F., Gnoffo, P., Manual for (LAURA), TM 4674, 1996.], was used axisymmetric...
We consider squeeze-film gas damping during microbeam motion away and toward a substrate as it occurs opening closing of RF switches other MEMS devices with moving components. The numerical solution the gas-damping problem in two-dimensional geometries is obtained based on Boltzmann?ES-BGK equation. difference force between downward- upward-moving beam gap-to-width ratio 34 shown to vary from little 5% for low velocities 0.1 m s?1 more than 200% at 2.4 s?1. For constant velocity magnitude...
The effect of intermolecular potentials on compressible, planar flow in slip and transitional regimes is investigated using the direct simulation Monte Carlo method. Two interaction models, variable hard sphere (VHS) Lennard-Jones (LJ) are first compared for subsonic supersonic Couette flows argon at temperatures 40, 273, 1,000 K, then regime ranging from Knudsen numbers (Kn) 0.0051 to 1. binary scattering model elastic potential proposed recently [A. Venkattraman A. Alexeenko, “Binary...
Uncertainty quantification (UQ) in the hypersonic flow regime offers valuable information to determine physical models need of improvement and assist design vehicles flight experiments. Here we present results UQ analysis based on polynomial chaos method flowfield surface heat flux uncertainty under typical blunt-body re-entry conditions. The NASA Langley code, LAURA, was used for axisymmetric CFD calculations chemically reacting over FIRE-II configuration. A third order (PC) using...
Plume-surface interaction (PSI) effects during propulsive landing are a major risk factor in the development of larger human class Mars and Moon landers. The NASA/MSFC Fluid Dynamics Branch is applying framework PSI simulation tools to predict plume impingement flow, plume-induced erosion cratering, debris transport deliver environments NASA commercial customer projects. Loci/CHEM program applied predicting flow with high-fidelity moving body capabilities for lander terminal descent...
View Video Presentation: https://doi.org/10.2514/6.2022-2319.vid As part of the Game Changing Development (GCD) Program funded by NASA's Space Technology Mission Directorate (STMD), development simulation capability for prediction extra-terrestrial plume surface interaction (PSI) environments has been undertaken Fluid Dynamics Branch at NASA/MSFC. The GCD PSI Project, planned to be completed over a four year period, contains Predictive Simulation Capability (PSC) Element focused on creating...
View Video Presentation: https://doi.org/10.2514/6.2022-1693.vid Plume-surface interactions between a rocket plume and the lunar surface will be studied in-situ during two of NASA's upcoming Commercial Lunar Payload Services Program missions. The payload, Stereo Cameras for Plume-Surface Studies (SCALPSS), employ multiple-camera photogrammetry system to obtain stereo images regolith before, during, after significant erosion subsequent crater formation. evaluation measurement capabilities...
The trailing-edge region of turbine airfoils is difficult to cool. In this study, CFD conjugate analysis based on the shear-stress transport (SST) turbulence model used study flow and heat transfer in a triple-impingement cooling configuration. Parameters studied include pressure drop across configuration (1, 2, 3, 4, 5 bars), coefficient hot-gas side (2,000, 4,000, 6,000 W/m2-K). all cases with analysis, temperature coolant at inlet passage 673 K, external 1,755 static exit 25 bars....
As part of the Game Changing Development (GCD) Program funded by NASA’s Space Technology Mission Directorate (STMD), development simulation capability for prediction extra-terrestrial plume surface interaction (PSI) environments has been undertaken Fluid Dynamics Branch at NASA/MSFC. The Predictive Simulation Capability (PSC) Element is focused on creating reliable and accurate PSI in Martian (~650 Pa) Lunar (vacuum) ambient environments. In this paper, an overview brief status one area...
The forced harmonic oscillator (FHO) model is an attractive choice for implementation into DSMC due to its higher accuracy over the LarsenBorgnakke (L-B) model, and fact that it still analytic expression. comes with complexity, several factors which may adversely affect simulations in particular must be addressed. Detailed balance, round-off errors, anharmonic energy limitations, all require some slight modification or cut-off values case of errors order ensure within simulations. In...
Unsteady, direct simulation Monte Carlo/particle-in-cell simulations of rocket plume expansions into the magnetosphere at geostationary Earth orbit are presented for three thruster pulse durations: 0.1, 1.4, and 9.9 s. The chemical ejects hydrazine combustion products a mass flow rate , number densities is computed as function time distances up to 35 km from thruster. reaches steady-state operation 1 downstream before shut off 1.4 s, reached far 20 s duration. An analytic expression free...
The effect of molecular models on viscosity and thermal conductivity calculations is investigated. Direct Simulation Monte Carlo (DSMC) method for rarefied gas flows used to simulate Couette Fourier as a means obtaining the transport coefficients. Experimental measurements argon (Ar) provide baseline comparison over wide temperature range 100–1,500 K. variable hard sphere (VHS), soft (VSS), Lennard-Jones (L-J) have been implemented into parallel version Bird's one-dimensional DSMC code,...
Unsteady, direct simulation Monte Carlo (DSMC)-particle-in-cell (PIC) simulations of rocket plume expansions into the magnetosphere at geostationary Earth orbit (GEO) are presented for three thruster pulse durations: 0.1 s, 1.4 and 9.9 s.The chemical ejects hydrazine combustion products a mass flow rate 4.5 × 10 -4 kg/s, number densities computed as function time distances up to 35 km from thruster.The reaches steady-state operation 1 downstream before is shut off reached far 20 s...