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 Luise September 15, 2007 08:22

direction vector in porous media

Hello,

I was wondering if someone could clarify what exactly the direction vector is in the porous media panel. Is it the direction of the medium with respect to the principal axes of my coordinate system? And does it have anything to do with the viscous coefficient?

 AAA September 15, 2007 20:08

Re: direction vector in porous media

Hi

The directions you specify in this panel are used to specify the directions of the viscous and inertial resistences. So if say the flow within the porous medium is in the x- direction of your domain, and you know the resistences in that direction, you should specify the direction vector accourdingly.

Regards

 Luise September 16, 2007 05:32

Re: direction vector in porous media

Well my model is 2d and i have flow in both directions. I know that the viscous resistance in the y-direction is 10 times larger than that in the x-direction.so does this mean that I have to set X=0.1 and Y=1 ?? (I do not have inertial resestance as my flow is laminar)

regards, Luise

 chandra manik September 17, 2007 05:34

Re: direction vector in porous media

I dont think so, that only sign of vector not quantity or scalar. You should check the constant value for inertial and viscous value, better u make experimental or test

 Luise September 17, 2007 06:28

Re: direction vector in porous media

As I get it the X and Y values are used to define the vector and not 'portion' of viscous resistance in each direction, right?

best, luise

 AAA September 17, 2007 20:45

Re: direction vector in porous media

Hi Luise,

The direction vectiors are only for specifying directions, not resistance magnitudes.

 chandra manik September 17, 2007 23:41

Re: direction vector in porous media

Right Luise, it is only direction, see user manual to find methode to calculated inertial resistance and viscous resistance, if u dont perform test on your porous media, using Van Winkle equation, but the most accurate to perform field test so u know the characteristic of your porous. In Convert field test result constant value (viscous and inertial constant) see FAQ in this site

i hope it could help

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