Compressible Convection in Planetary Mantles: a Comparison of Different Models
Speaker: Dr. Jezabel Curbelo - Universitat Politècnica de Catalunya
Date: Feb 15, 2023; Time: 10:30 AM Location: UTEB 476
Abstract
In numerical modeling of planetary and stellar convection, taking into account compressibility effects is crucial. However, using the exact equations may not be feasible due to the generation of fast acoustic waves, which distract from the slower convective motions caused by buoyancy. The Oberbeck-Boussinesq model simplifies the calculations by suppressing the acoustic waves making it easier for numerical simulations, but is so simple and pressure effects are relegated to a secondary role. Intermediate models, such as the anelastic and anelastic liquid models, have also been proposed to balance simplicity and accuracy.
We investigated compressible convection under several different approximations for the thermodynamic state as well as using the exact equations. We tested two different classes of equations of state (EoS): one where entropy depends only on density, resulting in nearly constant density and minimizing non-Oberbeck-Boussinesq effects, and the Birch-Murnaghan equations of state, which are realistic models for condensed matter like the Earth’s mantle and core. Our study showed that dissipation is closely linked to the fraction of heat flow carried by entropy flux. Additionally, we observe that small-scale convection is prevalent in the flow structure. Our results are mostly discussed in the framework of mantle convection, but the EoS is flexible enough to be applied in the inner core or in icy planets.
Bio
Jezabel Curbelo is a Ramon y Cajal Research Fellow at Barcelona School of Industrial Engineering at Universitat Politècnica de Catalunya, and currently visiting the Department of Earth and Planetary Sciences at Harvard University. She has previously held positions at various universities, including the Department of Atmospheric and Oceanic Sciences at UCLA and the Laboratoire de Géologie de Lyon. Her PhD thesis (Universidad Autónoma de Madrid, 2014) was awarded with the “2015 Donald L. Turcotte Award” (American Geophysical Union). She has received several awards for her research in geophysical fluid dynamics including the ”Leonardo Fellowships 2022” (BBVA Foundation) and the ”2021 L’Oréal-UNESCO For Women in Science” award (L’Oréal Spain). Her research focuses on the simulation and modeling of nonlinear fluid processes in the ocean and atmosphere and the analysis of convective motions in planetary mantles. Her webpage is web.mat.upc.edu/jezabel.curbelo/.