Nathaniel Morgan

Los Alamos National Laboratory
• Computational Physics Division, 2010 - present
• Applied Physics Division, 2005 - 2010
• Theoretical Division, 2003
• Engineering Sciences and Applications Division, 2001-2002

• Computational physics, mathematics, and engineering.
• Research interests range from computer science to creating transformative numerical methods suitable for predicative simulations of multidimensional high-speed flows with shocks, contact discontinuities, disparate materials, complex strength models, and diverse equations of state.
• Developing high-order discontinuous Galerkin (DG) methods for simulating large deformation flows, and on creating an explicit gas and solid dynamics code that is performant on super computers built with heterogeneous processors such as GPUs

Recent Journal Papers

• E. Lieberman, N. R. Morgan, D. J. Luscher, and D. E. Burton, A higher-order Lagrangian discontinuous Galerkin hydrodynamic method for elastic-plastic flows, Journal of Computers and Mathematics with Applications, 8/2018; DOI: 10.1016/j.camwa.2018.08.020
• X. Liu, N. R. Morgan, and D. E. Burton, Lagrangian discontinuous Galerkin hydrodynamic methods in axisymmetric coordinates, Journal of Computational Physics, 07/2018; 373; DOI: 10.1016/j.jcp.2018.06.073
• N. R. Morgan, X. Liu, and D. E. Burton, Reducing spurious mesh motion in Lagrangian finite volume and discontinuous Galerkin hydrodynamic methods, Journal of Computational Physics, 06/2018; 372; DOI: 10.1016/j.jcp.2018.06.008
• V. Chiravalle and N. R. Morgan, A 3D Lagrangian cell-centered hydrodynamic method with higher-order reconstructions for gas and solid dynamics, Journal of Computers and Mathematics with Applications, 06/2018; DOI: 10.1016/j.camwa.2018.06.011
• A. Barlow, N. R. Morgan, M. Shashkov, Constrained optimization framework for interface-aware sub-scale dynamics discrete closure model for multimaterial cells in Lagrangian cell-centered hydrodynamics. Journal of Computers and Mathematics with Applications, 06/2018; DOI: 10.1016/j.camwa.2018.06.015
• T. Wu, M. Shashkov, N. R. Morgan, H. Luo, and D. Kuzmin, An updated Lagrangian discontinuous Galerkin hydrodynamic method for gas dynamics, Journal of Computers and Mathematics with Applications,04/2018; DOI: 10.1016/j.camwa.2018.03.040
• X. Liu, N. R. Morgan, D.E. Burton: A Lagrangian discontinuous Galerkin hydrodynamic method. Computers & Fluids 12/2017; DOI:10.1016/j.compfluid.2017.12.007
• D.E. Burton, N. R. Morgan, M.R.J. Charest, M.A. Kenamond, J. Fung: Compatible, energy conserving, bounds preserving remap of hydrodynamic fields for an extended ALE scheme. Journal of Computational Physics 11/2017; 355., DOI:10.1016/j.jcp.2017.11.017
• J. Bakosi, J. Waltz, N. R. Morgan: Improved ALE mesh velocities for complex flows. International Journal for Numerical Methods in Fluids 05/2017; 85(11)., DOI:10.1002/fld.4403
• N. R. Morgan, J. I. Waltz: 3D level set methods for evolving fronts on tetrahedral meshes with adaptive mesh refinement. Journal of Computational Physics 05/2017; 336:492-512., DOI:10.1016/j.jcp.2017.02.030
• V. P. Chiravalle, N. R. Morgan: A 3D Finite Element ALE Method using an Approximate Riemann Solution. International Journal for Numerical Methods in Fluids 07/2016; DOI:10.1002/fld.4284
• C. C. Pederson, B. L. Brown, N. R. Morgan: The Sedov blast wave as a radial piston verification test. 05/2016;, DOI:10.1115/1.4033652
• D. Burton, N. R. Morgan, T. Carney, M. Kenamond: Reduction of dissipation in Lagrange cell-centered hydrodynamics (CCH) through corner gradient reconstruction (CGR). Journal of Computational Physics 07/2015; 299:229., DOI:10.1016/j.jcp.2015.06.041
• M. R. J. Charest, T. R. Canfield, N. R. Morgan, J. Waltz, J. G. Wohlbier: A high-order vertex-based central ENO finite-volume scheme for three-dimensional compressible flows. Computers & Fluids 07/2015; 114., DOI:10.1016/j.compfluid.2015.03.001
• N. R. Morgan, J. I. Waltz, D. E. Burton, M. R. Charest, T. R. Canfield, J. G. Wohlbier: A point-centered arbitrary Lagrangian Eulerian hydrodynamic approach for tetrahedral meshes. Journal of Computational Physics 02/2015; 290., DOI:10.1016/j.jcp.2015.02.024
• J. Waltz, J. G. Wohlbier, L. D. Risinger, T. R. Canfield, M. R. J. Charest, A. R. Long, N. R. Morgan: Performance analysis of a 3D unstructured mesh hydrodynamics code on multi-core and many-core architectures. International Journal for Numerical Methods in Fluids 11/2014; 77(6)., DOI:10.1002/fld.3982
• N. R. Morgan, J. I. Waltz, D. E. Burton, M. R. Charest, T. R. Canfield, J. G. Wohlbier: A Godunov-like point- centered essentially Lagrangian hydrodynamic approach. Journal of Computational Physics 10/2014; 281., DOI:10.1016/j.jcp.2014.10.048
• J. Waltz, N. R. Morgan, T. R. Canfield, M. R. J. Charest, J. G. Wohlbier: A nodal Godunov method for Lagrangian shock hydrodynamics on unstructured tetrahedral grids. International Journal for Numerical Methods in Fluids 09/2014; 76(3)., DOI:10.1002/fld.3928
• J. Waltz, T. R. Canfield, N. R. Morgan, L. D. Risinger, J. G. Wohlbier: Manufactured solutions for the three- dimensional Euler equations with relevance to Inertial Confinement Fusion. Journal of Computational Physics 06/2014; 267:196–209., DOI:10.1016/j.jcp.2014.02.040
• N. R. Morgan, K. N. Lipnikov, D. E. Burton, M. A. Kenamond: A Lagrangian staggered grid Godunov-like approach for hydrodynamics. Journal of Computational Physics 01/2014; 259:568-597., DOI:10.1016/j.jcp.2013.12.013
• N. R. Morgan: A dissipation model for staggered grid Lagrangian hydrodynamics. Computers & Fluids 08/2013; 83:48-57., DOI:10.1016/j.compfluid.2012.05.018
• D. E. Burton, T. C. Carney, N. R. Morgan, S. K. Sambasivan, M. J. Shashkov: A cell-centered Lagrangian Godunov-like method for solid dynamics. Computers & Fluids 08/2013; 83:33-47., DOI:10.1016/j.compfluid.2012.09.008
• J. Waltz, T. R. Canfield, N. R. Morgan, L. D. Risinger, J. G. Wohlbier: Verification of a three-dimensional unstructured finite element method using analytic and manufactured solutions. Computers & Fluids 07/2013; 81:57-67., DOI:10.1016/j.compfluid.2013.03.025
• N. R. Morgan, M. A. Kenamond, D. E. Burton, T. C. Carney, D. J. Ingraham: An Approach for treating contact surfaces in Lagrangian cell-centered hydrodynamics. Journal of Computational Physics 05/2013; In press., DOI:10.1016/j.jcp.2013.05.015
• J. Waltz, N. R. Morgan, T. R. Canfield, M. R. Charest, L. D. Risinger, J. G. Wohlbier: A three-dimensional finite element arbitrary Lagrangian-Eulerian method for shock hydrodynamics on unstructured grids. Computers & Fluids 01/2013; 92., DOI:10.1016/j.compfluid.2013.12.021

Recent Conference Papers

• X. Liu, N. R. Morgan, D. E. Burton: A comparative study of two different methods for RZ axisymmetric coordinates in context of Lagrangian discontinuous Galerkin hydrodynamics. AIAA Aviation and Aeronautics Forum and Exposition (AIAA AVIATION 2018), Atlanta, GA; 06/2018
• X. Liu, N. R. Morgan, D. E. Burton: A Lagrangian cell-centered discontinuous Galerkin hydrodynamic method for 2D Cartesian and RZ axisymmetric coordinates. 2018 AIAA SciTech Forum, Kissimm; 01/2018
• N. R. Morgan, X. Liu, D. E. Burton: A Lagrangian discontinuous Galerkin hydrodynamic method for higher-order triangular elements. 2018 AIAA SciTech Forum, Kissimmee, Fl; 01/2018
• M. R. Charest, T. R. Canfield, N. R. Morgan, J. Waltz, J.G Wohlbier: A high-order finite-volume method for compressible flows on moving tetrahedral grids. 53rd AIAA Aerospace Sciences Meeting; 01/2015, DOI:10.2514/6.2015-0297
• M. R. Charest, T. R. Canfield, N. R. Morgan, J. Waltz, J. G. Wohlbier: A vertex-based high-order finite-volume scheme for three-dimensional compressible flows on tetrahedral mesh. 11th World Congress on Computational Mechanics; 07/2014

Recent Conference Presentations

• N. Morgan, X. Liu, D. Burton, A subcell method for stable mesh motion with Lagrangian hydrodynamic methods on quadratic elements, ECCOMAS June 2018
• D. Burton, N. Morgan, X. Liu, A compatible Lagrangian discontinuous Galerkin hydrodynamic method for 2D and 3D gas dynamics, ECCOMAS June 2018
• E. Lieberman, N. Morgan, D.J. Luscher, D. Burton, A higher-order Lagrangian discontinuous Galerkin hydrodynamic method for elastic-plastic flows, ECCOMAS June 2018
• V. Chiravalle, N. Morgan, A new approach for multi-material cells in cell-centered hydrodynamics, ECCOMAS June 2018
• X. Liu, N. R. Morgan, D. E. Burton: A comparative study of two different methods for RZ axisymmetric coordinates in context of Lagrangian discontinuous Galerkin hydrodynamics. AIAA June 2018
• N. Morgan, X. Liu, and D. Burton, A Lagrangian discontinuous Galerkin hydrodynamic method for higher-order triangular elements, AIAA Jan. 2018
• X. Liu, N. Morgan, and D. Burton, A Lagrangian cell-centered discontinuous Galerkin hydrodynamic method for 2D Cartesian and RZ axisymmetric coordinates, AIAA Jan. 2018
• N. Morgan, X. Liu, and D. Burton, Reducing spurious motion in Lagrangian hydrodynamics. MultiMat 2017: International Conference on Numerical Methods for Multi-Material Fluid Flows, Santa Fe; 09/2017
• V. Chiravalle and N. Morgan, A limiting approach for higher-order Lagrangian cell-centered hydrodynamic (CCH) methods. MultiMat 2017: International Conference on Numerical Methods for Multi-Material Fluid Flows, Santa Fe; 09/2017
• A. Barlow, N. R. Morgan, M. Shashkov, Constrained optimization framework for interface-aware sub-scale dynamics discrete closure model for multimaterial cells in Lagrangian cell-centered hydrodynamics. MultiMat 2017: International Conference on Numerical Methods for Multi-Material Fluid Flows, Santa Fe; 09/2017
• D. E. Burton, N. R. Morgan, T. C. Carney, M. A. Kenamond, B. J. Brown: Corner gradient reconstruction (CGR) and the reduction of dissipation in Lagrange cell-centered hydrodynamics (CCH), LA-UR-15-26769. MultiMat 2015, International Conference on Numerical Methods for Multi-Material Fluid Flows, Wurzburg, Germany; 09/2015
• N. R. Morgan: A presentational on a 3D Arbitrary Lagrangian Eulerian (ALE) hydrodynamic approach for tetrahedral meshes. MultiMat 2015, International Conference on Numerical Methods for Multi-Material Fluid Flows, Wurzburg, Germany; 09/2015
• M. R. Charest, T. Canfield, N. Morgan, J. Waltz, J. Wohlbier: A high-order finite-volume method for compressible flows on moving tetrahedral grids. 53rd AIAA Aerospace Sciences Meeting; 01/2015, DOI:10.2514/6.2015-0297
• M. R. J. Charest, T. R. Canfield, N. R. Morgan, J. Waltz, J. G Wohlbier: A vertex-based high-order finite-volume scheme for three-dimensional compressible flows on tetrahedral mesh. 11th World Congress on Computational Mechanics; 07/2014
• D. E Burton, M. A. Kenamond, N. R. Morgan, T.C. Carney, M.J. Shashkov: An intersection based ALE scheme (xALE) for cell centered hydrodynamics (CCH), LA-UR-13-26756.2. Multimat 2013, International Conference on Numerical Methods for Multi-Material Fluid Flows; 09/2013
• N. R. Morgan, J. Waltz, D.E. Burton, T. Canfield, L.D. Risinger, J. Wohlbier, M. Charest: A Godunov-like point- centered ALE finite element hydrodynamic approach, LA-UR-13-26722. Multimat 2013, International Conference on Numerical Methods for Multi-Material Fluid Flows; 09/2013
• J. Waltz, T. Canfield, M. Charest, N. Morgan, L. Risinger, and J. Wohlbier, “Operator splitting and time accuracy in Lagrange plus remap methods”, Multimat 2013, International Conference on Numerical Methods for Multi-Material Fluid Flows; 09/2013
• J. Wohlbier, L. Risinger, T. Canfield, M. Charest, N. Morgan, and J. Waltz, “Programming for modern architectures in the CHICOMA hydrocode”, Multimat 2013, International Conference on Numerical Methods for Multi-Material Fluid Flows; 09/2013
• T. Canfield, M. Charest, N. Morgan, L. Risinger, J. Waltz, and J. Wohlbier, “Simulation of multi-material flows using a finite element Riemann solver and adaptive unstructured grids”, Multimat 2013, International Conference on Numerical Methods for Multi-Material Fluid Flows; 09/2013