Setting a Variable Temperature Profile

kerbelian · June 8, 2012, 13:45

Hello,

I need to set a temperature at a boundary condition that varies or reduces as the height of the boundary grows. I tried creating an expression of the form:

Temp=0.008*z+300 [K]

Where z is the z coordinate, but it gave me an error message telling me that I can't assign a dimension to a non-dimension variable as distance. In other words, I can't tell CFX that z is Kelvin and not m. And besides since there is an addition in the formula, it also showed that the dimensions wouldn't match since there is temperature and distance in it.

Any advise for what can I do about this?

PD: The boundary condition has a semi-cylindrical shape with a variable height between -3 and 73 m

lffabiani · June 8, 2012, 16:49

Have you tried

Temp=0.008 [K m^-1]*z+300 [K]

The last [K] is assigned only to the "300" part, not the whole eq.

On the same window where you set the variable, there is an "Evaluate" option, where you can see what will happen to the variable (in your case Temp) changing the inputs (in your case Z)

Best regards

June 8, 2012, 13:45	Setting a Variable Temperature Profile	#1
kerbelian New Member Michael Mera Join Date: Jun 2012 Posts: 1 Rep Power: 0	Hello, I need to set a temperature at a boundary condition that varies or reduces as the height of the boundary grows. I tried creating an expression of the form: Temp=0.008*z+300 [K] Where z is the z coordinate, but it gave me an error message telling me that I can't assign a dimension to a non-dimension variable as distance. In other words, I can't tell CFX that z is Kelvin and not m. And besides since there is an addition in the formula, it also showed that the dimensions wouldn't match since there is temperature and distance in it. Any advise for what can I do about this? PD: The boundary condition has a semi-cylindrical shape with a variable height between -3 and 73 m

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Inlet won't apply UDF and has temperature at 0K!	tccruise	Fluent UDF and Scheme Programming	2	September 14, 2012 07:08
Please Help! Temperature profile UDF for 3D geometry	subhankar_bhandari	FLUENT	2	April 16, 2011 06:30
Simulation of a Silo	Attesz	CFX	20	October 15, 2010 09:11
Cells with t below lower limit	Purushothama	Siemens	2	May 31, 2010 22:58
Ultra high temperature?	bk	Siemens	2	July 19, 2005 01:01

June 8, 2012, 16:49		#2
lffabiani Member Luis Filipe Fabiani Join Date: Apr 2009 Posts: 43 Rep Power: 17	Have you tried Temp=0.008 [K m^-1]*z+300 [K] The last [K] is assigned only to the "300" part, not the whole eq. On the same window where you set the variable, there is an "Evaluate" option, where you can see what will happen to the variable (in your case Temp) changing the inputs (in your case Z) Best regards