# MHD solvers ? mhdFoam, axisymmetric case

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 March 22, 2016, 08:05 MHD solvers ? mhdFoam, axisymmetric case #1 New Member   Join Date: Mar 2016 Posts: 14 Rep Power: 10 Hello, I would like to have some help about the case I need to compute, since I'm a beginner with openFoam. I need to determine first the type of boundary conditions to use, and then the solver. Here is my case : I need to compute the velocity of a fluid inside a closed cylinder, under a constant (direction and time) magnetic field, and electric potential field, under normal pressure and temperature conditions. The motion of the fluid should be given by the combination of the two electric and magnetic fields, according to the main mhd equations. Because of the direction of the fields, the fluid's motion will be circular inside the cylinder. Therefore the case is axisymmetric, so I just need to use a 2D rectangular domain, with x=0 from the central axis of the cylinder, to x=Radius of the cylinder. I read a tutorial teaching how to implement such an axisymmetric domain, using "wedge" boudary types. But the flow in this tutorial was from top to bottom, and not coming from the "wedges" faces, and not free. But my main problem is to know if I can use the mhdFoam solver alone or if I need to modify it. It don't get if this solver can make a fluid moving, given a magnetic field. In the official openfoam tutorial for mhdFoam, the velocity field of the fluid is part of the initial conditions. But in my case it's not : I want openfoam to compute it. Should I put an already moving fluid in my initial conditions, or a still fluid ? What does mhdFoam really compute ? I don't really understand the small description of the .C file of the solver. I just found the EHDfoam (electroHydrodynamic solver) that seems to compute the fluid motion, given an electrostatic field. Should I couple both solvers ? An other source from an academic research team have made a presentation during the 2010 annual openFoam workshop, using the "Electric Potential Method" in order to solve some mhd cases, and a similar project here. Which solvers do you think I should work on ? How will I manage the velocity field in the boundaries of the domain ? Thank you for your help ! Romain linyanx likes this.

 March 24, 2016, 05:33 #2 New Member   Join Date: Mar 2016 Posts: 14 Rep Power: 10 up ! Nobody ever used the mhdFoam solver ?

 May 30, 2024, 06:50 #3 New Member   Omar Join Date: Apr 2024 Posts: 8 Rep Power: 2 Hello!!Did you figure out a solution to your problem?I know it's been 8 years but still if you did can you please explain to me what actually is the mhdsolver because as soon as i modify anything included in the tutorial it gives me the weirdest possible results.Like for example if i want to change the fluid properties like the sigma and permittivity, it instantly gives me a non convergence with the calculation.If you can help me figure this out it would be greatly appreciated

 Tags mhd mhdfoam axisymmetric