Publications

Crockatt, Michael M.; Shadid, John N.; Conde, Sidafa C.; Pawlowski, Roger P.; Mabuza, Sibu M.

Abstract not provided.

Conde, Sidafa C.

Abstract not provided.

Mechanics Research Communications

Sondak, David; Smith, Thomas M.; Pawlowski, Roger P.; Conde, Sidafa C.; Shadid, John N.

The variational multiscale (VMS) formulation is used to develop residual-based VMS large eddy simulation (LES) models for Rayleigh-Bénard convection. The resulting model is a mixed model that incorporates the VMS model and an eddy viscosity model. The Wall-Adapting Local Eddy-viscosity (WALE) model is used as the eddy viscosity model in this work. The new LES models were implemented in the finite element code Drekar. Simulations are performed using continuous, piecewise linear finite elements. The simulations ranged from Ra=106 to Ra=1014 and were conducted at Pr=1 and Pr=7. Two domains were considered: a two-dimensional domain of aspect ratio 2 with a fluid confined between two parallel plates and a three-dimensional cylinder of aspect ratio 1/4. The Nusselt number from the VMS results is compared against three dimensional direct numerical simulations and experiments. In all cases, the VMS results are in good agreement with existing literature.

Crockatt, Michael M.; Shadid, John N.; Conde, Sidafa C.; Pawlowski, Roger P.; Mabuza, Sibu M.

Abstract not provided.

Journal of Computational Physics

Miller, Sean M.; Cyr, E.C.; Shadid, John N.; Kramer, R.M.J.; Phillips, Edward G.; Conde, Sidafa C.; Pawlowski, Roger P.

Multi-fluid plasma models, where an electron fluid is modeled in addition to multiple ion and neutral species as well as the full set of Maxwell's equations, are useful for representing physics beyond the scope of classic MHD. This advantage presents challenges in appropriately dealing with electron dynamics and electromagnetic behavior characterized by the plasma and cyclotron frequencies and the speed of light. For physical systems, such as those near the MHD asymptotic regime, this requirement drastically increases runtimes for explicit time integration even though resolving fast dynamics may not be critical for accuracy. Implicit time integration methods, with efficient solvers, can help to step over fast time-scales that constrain stability, but do not strongly influence accuracy. As an extension, Implicit-explicit (IMEX) schemes provide an additional mechanism to choose which dynamics are evolved using an expensive implicit solve or resolved using a fast explicit solve. In this study, in addition to IMEX methods we also consider a physics compatible exact sequence spatial discretization. This combines nodal bases (H-Grad) for fluid dynamics with a set of vector bases (H-Curl and H-Div) for Maxwell's equations. This discretization allows for multi-fluid plasma modeling without violating Gauss' laws for the electric and magnetic fields. This initial study presents a discussion of the major elements of this formulation and focuses on demonstrating accuracy in the linear wave regime and in the MHD limit for both a visco-resistive and a dispersive ideal MHD problem.

Conde, Sidafa C.; Mabuza, Sibu M.; Shadid, John N.; Cyr, Eric C.; Smith, Thomas M.; Pawlowski, Roger P.

Abstract not provided.

Conde, Sidafa C.; Shadid, John N.; Gottlieb, Sigal G.; Grant, Zachary G.; Fekete, Imre F.

Abstract not provided.

Conde, Sidafa C.; Shadid, John N.; Imre, Fekete I.

Abstract not provided.

Mabuza, Sibusiso M.; Shadid, John N.; Conde, Sidafa C.; Cyr, Eric C.; Smith, Thomas M.; Pawlowski, Roger P.; Kuzmin, Dmitri K.

Abstract not provided.

Ober, Curtis C.; Pawlowski, Roger P.; Conde, Sidafa C.; Kalashnikova, Irina; Phipps, Eric T.; Phillips, Edward G.; Mota, Alejandro M.; Phlipot, Greg [.; Ridzal, Denis R.; Hansen, Michael A.; Fisher, Travis C.

Abstract not provided.

Bettencourt, Matthew T.; Kramer, Richard M.; Cartwright, Keith C.; Phillips, Edward G.; Ober, Curtis C.; Pawlowski, Roger P.; Swan, Matthew S.; Kalashnikova, Irina; Phipps, Eric T.; Conde, Sidafa C.; Cyr, Eric C.; Ulmer, Craig D.; Kordenbrock, Todd H.; Levy, Scott L.; Templet, Gary J.; Hu, Jonathan J.; Lin, Paul L.; Glusa, Christian A.; Siefert, Christopher S.; Glass, Micheal W.

This report documents the outcome from the ASC ATDM Level 2 Milestone 6358: Assess Status of Next Generation Components and Physics Models in EMPIRE. This Milestone is an assessment of the EMPIRE (ElectroMagnetic Plasma In Realistic Environments) application and three software components. The assessment focuses on the electromagnetic and electrostatic particle-in-cell solu- tions for EMPIRE and its associated solver, time integration, and checkpoint-restart components. This information provides a clear understanding of the current status of the EMPIRE application and will help to guide future work in FY19 in order to ready the application for the ASC ATDM L 1 Milestone in FY20. It is clear from this assessment that performance of the linear solver will have to be a focus in FY19.

Pawlowski, Roger P.; Phillips, Edward G.; Shadid, John N.; Lin, Paul L.; Cyr, Eric C.; Conde, Sidafa C.; Bettencourt, Matthew T.; Phipps, Eric T.; Trott, Christian R.

Abstract not provided.

Pawlowski, Roger P.; Phillips, Edward G.; Shadid, John N.; Cyr, Eric C.; Conde, Sidafa C.; Bettencourt, Matthew T.; Phipps, Eric T.; Bond, Stephen D.; Trott, Christian R.

Abstract not provided.

Ober, Curtis C.; Pawlowski, Roger P.; Kalashnikova, Irina; Conde, Sidafa C.; Cyr, Eric C.

Abstract not provided.

Mayr, Matthias M.; Cyr, Eric C.; Shadid, John N.; Pawlowski, Roger P.; Wildey, Timothy M.; Scovazzi, Guglielmo S.; Zeng, Xianyi Z.; Phillips, Edward G.; Conde, Sidafa C.

Abstract not provided.

Mayr, Matthias M.; Cyr, Eric C.; Shadid, John N.; Pawlowski, Roger P.; Wildey, Timothy M.; Scovazzi, Guglielmo S.; Zeng, Xianyi Z.; Phillips, Edward G.; Conde, Sidafa C.

Abstract not provided.

Miller, Sean M.; Cyr, Eric C.; Shadid, John N.; Conde, Sidafa C.; Phillips, Edward G.

Abstract not provided.

Conde, Sidafa C.; Gottlieb, Sigal G.; Shadid, John N.

Abstract not provided.

Pawlowski, Roger P.; Bartlett, Roscoe B.; Bettencourt, Matthew T.; Carleton, James B.; Conde, Sidafa C.; Cyr, Eric C.; Kim, Kyungjoo K.; Mota, Alejandro M.; Perego, Mauro P.; Shadid, John N.; Sjaardema, Gregory D.; Toth, Alexander R.; Bradley, Andrew M.; Spotz, William S.; Ober, Curtis C.; Kalashnikova, Irina

Abstract not provided.