Application of RANS turbulence closure models to flows subjected to electromagnetic and buoyancy forces

• Turbulent magnetohydrodynamic flows are studied under the RANS framework.
• Electromagnetic modified k-εk-ε model is tested.
• Good qualitative agreement in a 2D channel flow with a wall-normal magnetic field.
• Suppression of turbulence is generally over predicted.
• Dramatic reorganization of roll cells was seen in 3D Rayleigh–Benard convection.

This paper considers the application of the Reynolds Averaged Navier–Stokes (RANS) approach to two types of electromagnetically influenced turbulent flows. The first is a fully-developed 2D channel flow with a magnetic field imposed in either the wall-normal direction (Hartmann flow), or in the streamwise direction. The second is that of Rayleigh–Bénard convection with a vertical magnetic field imposed. The turbulence is represented by a low-Re  k-εk-ε model which is tested with and without electromagnetic modifications proposed by Kenjereš and Hanjalić (2000). The results show the modifications lead to a dramatic reorganisation of the coherent structures in Rayleigh–Bénard convection as the magnetic field strength is increased, but overpredict the damping of the turbulent shear stress in a simple channel flow.