New exact solutions for unsteady magnetohydrodynamic MHD flows of an Oldroyd-B fluid have been derived. The Oldroyd-B fluid saturates the porous space. Two different flow cases have been considered. The analytical expressions for velocity and shear stress fields have been obtained by using Laplace transform technique. The corresponding solutions for hydrodynamic OldroydB fluid in a nonporous sp...

Nonequilibrium Alfvénic flows have been observed in plasma jets during the helicity injection stage of the Caltech spheromak experiment. Density and time of flight measurements of these jets show that the flows convect dense plasma (beta approximately 1) because of the axial gradient in the current channel profile. A simplified MHD theory is derived to model the flow.

Magnetohydrodynamic (MHD) flows are governed by Navier–Stokes equations coupled with Maxwell equations through coupling terms. We prove the unconditional stability of a partitioned method for the evolutionary full MHD equations, at high magnetic Reynolds number, written in the Elsässer variables. The method we analyze is a first-order onestep scheme, which consists of implicit discretization of...

The MHD flows are governed by the Navier-Stokes equations coupled with the Maxwell equations through coupling terms. We prove the unconditional stability of a partitioned method for the evolutionary full MHD equations, at high magnetic Reynolds number, in the Elsässer variables. The method we propose is a defect correction second order scheme, and entails the implicit discretization of the subp...

In the present paper, we have studied MHD free convective two dimensional unsteady viscous incompressible flows through a porous effect bounded by an infinite vertical porous plate with constant suction. The permeability of the porous medium fluctuates in time about a constant mean, and the viscosity of fluid is assumed to vary as a linear function of temperature. The flow is permitted under th...

A consistent and conservative scheme designed by Ni et al. for the simulation of MHD flows with low magnetic Reynolds number has been implemented into a 3D parallel code of HIMAG based on solving the electrical potential equation. The scheme and code are developed on an unstructured collocated mesh, on which velocity (u), pressure (p), and electrical potential ( ) are located in the cell center...

In magnetohydrodynamic (MHD) flows turbulence reduction occurs due to the Joule dissipation. It results in heat transfer degradation. In open channel flows, heat transfer degradation is also caused by the turbulence redistribution near the free surface. Both effects can be significant in fusion applications with low-conductivity fluids such as molten salts. In the present study, the ‘‘K–e’’ mod...

In this paper, several low and high Reynolds number versions of k-ε and Reynolds stress turbulence models have been evaluated in a channel and a square duct flow with and without a magnetic field by comparing the predictions with direct numerical simulations data. The simulations are performed using FLUENT solver. The additional source terms for magnetic field effects on turbulence have been in...

Design widows on free surface flows in the APEX study are derived from the viewpoints of the free surface heat transfer, the adaptation of liquid flows to the topological constraints, and temperature requirements for plasma operation and power conversion efficiency. Within these constraints, the temperature of the free liquid surface facing the plasma is the most critical parameter governing th...