EGU22-9069
https://doi.org/10.5194/egusphere-egu22-9069
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Simulation of 3D transient superstructures in mantle convection and variable viscosity via the Lattice Boltzmann Method

Peter Mora1, Gabriele Morra2, and Dave Yuen3,4
Peter Mora et al.
  • 1Geoscience Department, CPG, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia (wolop2008@gmail.com)
  • 2Department of Physics and School of Geosciences, University of Louisiana at Lafayette, Lafayette, Louisiana, USA (gabrielemorra@gmail.com)
  • 3Department of Applied Physics and Applied Mathematics, Columbia University, New York, USA (daveyuen@gmail.com)
  • 4Department of Information Science and Engineering and College of Marine Geosciences, Ocean University of China, Qingdao, China (daveyuen@gmail.com)

Transient superstructures in mantle convection whose life and morphology vary with Rayleigh and Prandtl number have recently been demonstrated. These superstructures appear to be a two-scale phenomenon where smaller scale rolls organize into larger scale convection cells. Simulation of such superstructures requires the ability to model 3D convection in box with very large width/height ratio of order greater than 10, and with resolution to resolve the thermal boundary layer at Rayleigh numbers of 108 to 1010, respectively at least 100 height levels and 200 height levels. We achieve this with an efficient parallel implementation of the Lattice Boltzmann Method using Python which operates with high efficiency and linear speedup on thousands of cores. We present simulations with Rayleigh numbers of up to 1010 and Prandtl numbers from 1 to 100 to illustrate covering regimes from a magma ocean to solid mantle convection. We further present simulations using the LBM to model variable viscosity – specifically, temperature dependent– and illustrate the existence of pulsating plumes. We further demonstrate power law scaling between Nusselt number and Rayleigh number Nu  ~ Rag, which to first order is consistent with the Grossmann and Lohse theory.

How to cite: Mora, P., Morra, G., and Yuen, D.: Simulation of 3D transient superstructures in mantle convection and variable viscosity via the Lattice Boltzmann Method, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9069, https://doi.org/10.5194/egusphere-egu22-9069, 2022.