Problem with source cfx

TallesC · March 6, 2013, 20:53

The problem below is informed:

Expression resolves to invalid units ('kg m^-3 s^-1') in value set for parameter 'Total Source' in object '/FLOW:Flow Analysi1/DOMAIN:serpentina/BOUNDARY

ut serpentina/BOUNDARY SOURCE/SOURCES/EQUATION SOURCE:C2H3Cl mvc.mf'. Expected units: 'kg s^-1'.

how could resolved this problem??

evcelica · March 6, 2013, 22:57

Um . . . divide by m^-3 . . . . really?

TallesC · March 6, 2013, 23:10

I did not, how exactly do I do this?

evcelica · March 7, 2013, 05:29

Your expression has the wrong units. You are giving it a concentration per second, and it is expecting a mass per second. Fix your expression so that it gives the expected units.

ghorrocks · March 7, 2013, 05:41

barney=1[kg s^-1]
fred=barney/1[m^3]

Now fred is in kg m^-3 s^-1

But even better - Erik's suggestion is that this means the expression calculating it is probably wrong. If the units do not check out the numbers have no hope of being right so dividing by m^-3 is not going to fix the real error.

TallesC · March 7, 2013, 08:51

Problem i'm creating a subdomain...before a try ina a boundary...thanks a lot!!1

March 6, 2013, 20:53	Problem with source cfx	#1
TallesC Senior Member Talles Caio Join Date: Oct 2012 Location: Brazil Posts: 101 Rep Power: 14	The problem below is informed: Expression resolves to invalid units ('kg m^-3 s^-1') in value set for parameter 'Total Source' in object '/FLOW:Flow Analysi1/DOMAIN:serpentina/BOUNDARYut serpentina/BOUNDARY SOURCE/SOURCES/EQUATION SOURCE:C2H3Cl mvc.mf'. Expected units: 'kg s^-1'. how could resolved this problem??

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March 6, 2013, 22:57		#2
evcelica Senior Member Erik Join Date: Feb 2011 Location: Earth (Land portion) Posts: 1,188 Rep Power: 23	Um . . . divide by m^-3 . . . . really?

March 6, 2013, 23:10		#3
TallesC Senior Member Talles Caio Join Date: Oct 2012 Location: Brazil Posts: 101 Rep Power: 14	I did not, how exactly do I do this?

March 7, 2013, 05:29		#4
evcelica Senior Member Erik Join Date: Feb 2011 Location: Earth (Land portion) Posts: 1,188 Rep Power: 23	Your expression has the wrong units. You are giving it a concentration per second, and it is expecting a mass per second. Fix your expression so that it gives the expected units.

March 7, 2013, 05:41		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	barney=1[kg s^-1] fred=barney/1[m^3] Now fred is in kg m^-3 s^-1 But even better - Erik's suggestion is that this means the expression calculating it is probably wrong. If the units do not check out the numbers have no hope of being right so dividing by m^-3 is not going to fix the real error.

March 7, 2013, 08:51		#6
TallesC Senior Member Talles Caio Join Date: Oct 2012 Location: Brazil Posts: 101 Rep Power: 14	Problem i'm creating a subdomain...before a try ina a boundary...thanks a lot!!1