Geomagnetic Field Perturbations Caused by the Turbulent Flow of a Conducting Fluid Around the Ball

The disturbances of the external magnetic field produced by a turbulent flow of a conducting incompressible liquid around a solid dielectric sphere are investigated. The fluid flow is calculated in the approximation of the RANS model, which takes into account the effects of turbulent viscosity. The COMSOL multiphysical simulation platform is used for numerical modelling of hydrodynamic and magnetic perturbations. The solution of the problem is obtained for an arbitrary orientation of the external magnetic field. The angular distribution and the decrease in amplitude of the magnetic disturbances with distance are studied numerically. The directions of maximum magnetic disturbances are determined. The area near the turbulent wake is investigated in detail. Approximate asymptotic laws of decrease of magnetic disturbances as a function of distance to the center of the ball are derived. The magnetic disturbances caused by laminar and turbulent regimes of the fluid flow around a sphere are compared.