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Using a function for Permeability value
Posted 15.07.2013, 14:54 GMT-4 Fluid & Heat, Materials 2 Replies
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Hello!
I am new to the software. I am modeling fluid flow through the annulus of a pipe coupled to a porous media and am using the Free and Porous Media Flow physics interface. The permeability of the porous material is a function dependant on length of the material. The equation (from experimental data) is: f(x)=exp(-0.077*x+3.9)
It will not let me put this in directly because:
a) x is only in meters, not meters squared
b) it is having trouble understanding exp(x), instead of just a value
Any ideas are appreciated!
Amber
I am new to the software. I am modeling fluid flow through the annulus of a pipe coupled to a porous media and am using the Free and Porous Media Flow physics interface. The permeability of the porous material is a function dependant on length of the material. The equation (from experimental data) is: f(x)=exp(-0.077*x+3.9)
It will not let me put this in directly because:
a) x is only in meters, not meters squared
b) it is having trouble understanding exp(x), instead of just a value
Any ideas are appreciated!
Amber
2 Replies Last Post 16.07.2013, 11:15 GMT-4
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Posted:
1 decade ago
Amber-
Use:
exp(-0.077*x[1/m]+3.9)[m^2]
Your function f(x) I bet is units of m^2. These are the correct units for permeability.
Also, I think you should be reading in the x dimension as unitless by adding the [1/m] after x.
My guess is that you were getting the expression to turn orange which is not a fatal error (usually just a units warning). You should, however, get a black expression if you use the function I gave above. As long as the expression in your edit field isn't red you will still be able to run the model (you just may have incorrect units).
Best regards,
Josh Thomas
AltaSim Technologies
Use:
exp(-0.077*x[1/m]+3.9)[m^2]
Your function f(x) I bet is units of m^2. These are the correct units for permeability.
Also, I think you should be reading in the x dimension as unitless by adding the [1/m] after x.
My guess is that you were getting the expression to turn orange which is not a fatal error (usually just a units warning). You should, however, get a black expression if you use the function I gave above. As long as the expression in your edit field isn't red you will still be able to run the model (you just may have incorrect units).
Best regards,
Josh Thomas
AltaSim Technologies
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Mr. Thomas,
Thank you for your response! That worked perfect. I appreciate the help!
Sincerely,
Amber
Thank you for your response! That worked perfect. I appreciate the help!
Sincerely,
Amber