UDS-diffusivity coefficient

UDS_rambler · July 15, 2010, 11:42

hello everybody! I'm trying to use a UDS model to describe the diffusion of species dissolved in a solution. I got the diffusivity coefficients I need in m^2/s but I can't understand whether using m^2/s as units for diffusivity is right, while next to the box in the drop-down list in materials properties the units are kg/m-s like viscosity. I thought I have to convert the diffusivity value in m^2/s, as Fickian diffusivity value for my species, to these units but it's a kind of freakingly strange thing I hope you can help me and i thank you as well!

chaozhong.qin · July 15, 2010, 16:29

Hi,

You have two different parameters of dynamic viscosity and species diffusivity. No change is needed.

UDS_rambler · July 15, 2010, 16:48

thank you for your prompt response!! So you mean I can simply use m^2/s as units, don't you? Because the theoretical formulation used in the user's guide confirms this fact, but the units you can find within the material panel for the diffusivity puzzled me!!...... thanks again for your attention!!

chaozhong.qin · July 15, 2010, 16:53

Hi,

I think so,

July 15, 2010, 11:42	UDS-diffusivity coefficient	#1
UDS_rambler New Member Giuse Join Date: Jul 2010 Location: Italy Posts: 21 Rep Power: 16	hello everybody! I'm trying to use a UDS model to describe the diffusion of species dissolved in a solution. I got the diffusivity coefficients I need in m^2/s but I can't understand whether using m^2/s as units for diffusivity is right, while next to the box in the drop-down list in materials properties the units are kg/m-s like viscosity. I thought I have to convert the diffusivity value in m^2/s, as Fickian diffusivity value for my species, to these units but it's a kind of freakingly strange thing I hope you can help me and i thank you as well!

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July 15, 2010, 16:29		#2
chaozhong.qin New Member Steven Qhin Join Date: Jul 2010 Posts: 15 Rep Power: 16	Hi, You have two different parameters of dynamic viscosity and species diffusivity. No change is needed.

July 15, 2010, 16:48		#3
UDS_rambler New Member Giuse Join Date: Jul 2010 Location: Italy Posts: 21 Rep Power: 16	thank you for your prompt response!! So you mean I can simply use m^2/s as units, don't you? Because the theoretical formulation used in the user's guide confirms this fact, but the units you can find within the material panel for the diffusivity puzzled me!!...... thanks again for your attention!!

July 15, 2010, 16:53		#4
chaozhong.qin New Member Steven Qhin Join Date: Jul 2010 Posts: 15 Rep Power: 16	Hi, I think so,