Effects of induced magnetic field on conducting viscous fluid flowing in a constricted channel

We report the effects of an externally applied magnetic field on an electrically conducting fluid flow in a locally constricted channel. With the use of finite-difference discretization and the ADI (Alternating directions implicit) scheme, the non-linear coupled magnetohydrodynamic (MHD) equations in two dimensions were numerically solved. When the magnetic Reynolds number R_M >> 1, an induced magnetic field forms in the motion and significantly affects flow. The electromagnetic force (Lorentz force) is developed and acts as a damping force. It results the suppression of flow separation regions developed due to the channel constrictions. It delays the onset of flow separation and the flow become stable. By employing suitable value of magnetic field one can completely suppress the flow separation. The induced magnetic field and current density vectors are dense at the constriction site due to high velocity shear in the downstream of the constriction, resulting in the creation of high shear magnetic and electric fields.