Numerical Projects
Using maching learning algorithms to represent subgrid processes in astrophysical fluids and plasmas
ML methods have been used to study subgrid proccesses in many scientific fields, including climate science. The most challenging aspects of using ML to model physical processes is that they make poor predictions when it comes to energy/mass conservation. Thus there has been growing efforts to use hybrid physics+ML models, which uses additional physical laws to constrain ML outputs, I am interested in developing such models for turbulence and fluid instabilities caused by various phenomena.
Developing a robust numerical algorithm to deal with inner boundary conditions in astrophysical simulations
In simulations especially concerning black hole and supernovae etc, given the flow outside the subgrid is not steady state and there are both inflow and outflow from the region, standard pressure boundary conditions usually result in the reflection of the outgoing waves. Thus non-reflecting boundary conditions are required, as they provide a special treatment to the domain boundaries to control these spurious wave reflections.
Porting subgrid modules from CPU into GPU-based architecture
The idea is as follows: In a large scale simulation, the grid will be divided into two meshes: the main grid including a large number of small mesh patches at different levels of refinement, spans the whole computational domain and is distributed across compute nodes using a space-filling curve. The uniform subgrid mesh is the one held within accelerator memory, and each GPU being used has a separate, independent subgrid. These subgrids are used to perform transient local simulations of the sub-resolution phenomena using boundary data interpolated from template regions on the main grid. This can solve the problem when we are not able to run simulations of the whole domain on GPU clusters.
Science Projects
- Primordial black holes – are they candidates for dark matter?
- Binary black hole mergers- what happens in the final parsec?
- Particle acceleration and composition in astrophysical jets, in particular AGN jets