Magnetohydrodynamic Turbulence: numerical simulation and study of the transition between two-dimensional and three-dimensional turbulence, with and without walls

• Applicant: Professor Dr. Alban Pothérat
• Subject Area: Fluid Mechanics
• Term: from 2005 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 13029236

The goal of this project is to study the mechanisms which govern the transition between twodimensional (2d) and three-dimensional (3d) turbulence in liquid metals under an externally imposed magnetic field. Although some aspects of this problem have already been studied, basic questions such as knowing whether the transition has an hysteresis, finding clear transition criteria expressed in terms of the relevant non-dimensional numbers, or understanding the influence of walls remain to this day unanswered. Those shall be the questions we want to address, using original numerical simulations and low-dimensional models. The models will be built by taking advantage of the tendency of this kind of turbulence to exhibit big anisotropic structures. We shall proceed in two main steps: firstly, we study the transition in the simpler case of a 3d periodic box. Secondly we tackle the problem of turbulence confined between two walls orthogonal to the imposed magnetic field, with periodic boundary conditions in the other directions of space. The difference between the results obtained in both case will point out the role played by the walls, and give a measure of the relevance of periodic boundary conditions to walls bound problems.

• DFG Programme: Research Grants
• International Connection: United Kingdom