Numerical Dynamics on Voronoi spherical grids for simulations with grid resolution at the "gray zone"

• Grant number: 23/00447-7
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: April 01, 2023
• End date: March 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Mathematics - Applied Mathematics
• Principal Investigator: Pedro da Silva Peixoto
• Grantee: Felipe Augusto Ventura de Bragança Alves
• Host Institution: Instituto de Matemática e Estatística (IME). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/06176-0 - Numerical methods for a new generation of weather and climate models, AP.PFPMCG.JP2

Abstract

Depending on the choice of numerics, different effects are present in the simulated flow that can potentially impact the Subgrid scale (SGS) model.The TRiSK numerical scheme used in MPAS is known to be subjected to the Hollingsworth instability which leads to the appearance of spurious small-scale waves, at the order of the grid spacing, that can grow in scale and taint larger scales, producing large scale physics-like phenomena that are due purely to numerical artifacts.In dynamic SGS models the fields obtained in the simulation are explicitly filtered to produce the SGS model.When using the TRiSK scheme, the fields are potentially tainted by numerical artifacts and its effects on dynamic SGS models are not well-known.The interaction between numerics and the dynamic SGS is also most likely affected by the ratio of the grid resolution and the turbulence outer scale of the problem.At the "gray zone", the peak of the turbulence energetics happens at the order of the grid spacing scale, the same scale where unphysical spurious waves are potentially generated by the TRiSK scheme.For this configuration it is unknown if the detrimental effects of numerical artifacts on the dynamic SGS model are magnified, since it is generated at scales highly relevant to the SGS model, or if the dissipative nature of the SGS will act more strongly on the spurious waves, therefore reducing the artificial effects of numerics on the model.Using MPAS, we plan to investigate this numerics-turbulence interaction across different scales, from mesoscale simulations to close-to-LES simulations - passing by the "gray zone" - hopefully generating insights to generate a "numerics aware" turbulence model, or, in an alternative view, a "turbulence aware" numerical scheme.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

GIRALDO, FRANCIS X.; ALVES, FELIPE A. V. DE BRAGANCA; KELLY, JAMES F.; KANG, SOONPIL; REINECKE, P. ALEX. A performance study of horizontally explicit vertically implicit (HEVI) time-integrators for non-hydrostatic atmospheric models. Journal of Computational Physics, v. 515, p. 22-pg., 2024-07-18. (23/00447-7)