Learning Forum

[Mohammad Qasem]

Hi

I want to simulate flow in a cylinder, but to simplify the simulation, I want to use a 2D domain with an axi-symmetric axis (x-axis). The question is, if i want to use the porous media, what direction-1 vector value (see the attached image) should be in this case.I want the porosity in the domain to be homogenous and isotropic in all directions regardless to flow direction. 

Thanks

[Rob]

The direction vectors are to help assign resistance values for "off axis" systems. So, in your as Direction-1 is along the x-axis you'll be adding the axial resistance to that direction and the radial resistance (y) as the other resistance value. 

Read the Cell Zones section of the Fluent User Guide (click on Help in Fluent) for more details. 

[Mohammad Qasem]

I refered to it but i still unable to understand it well. So based on the attached image where in Drection-1 Vectror the value of x =1 and y= 0 means that the resistance are in both axial and radial directions?

[Rob]

No, it means that Direction-1 is aligned to the x-axis. It's more for when you have a more complex geometry and a zone axis isn't aligned with x, y or z. In that scenario rather than trying to work out the resistance at an angle to the zone you can work out the Direction vectors instead.