LES diesel jet

Bdew8556 · August 20, 2019, 01:30

Hi guys,

I'm trying to simulate a diesel jet using LES.
I'm trying to run compressibleMultiInterFoam.

I think I'm getting close but I keep getting this error:

Creating field kinetic energy K

Courant Number mean: 0.0020326 max: 2487.28

--> FOAM FATAL ERROR:
Different dimensions for =
dimensions : [0 2 -1 0 0 0 0] = [1 -1 -1 0 0 0 0]

From function bool Foam::dimensionSet:

perator=(const Foam::dimensionSet&) const
in file dimensionSet/dimensionSet.C at line 171.

FOAM aborting

Any thoughts???

boundary93 · August 20, 2019, 04:04

Wrong unit

change it the way the solver already told you

Bdew8556 · August 20, 2019, 04:07

Thanks.

What file do I need to change though??

boundary93 · August 20, 2019, 08:29

It looks like the "nut" file

Bdew8556 · August 20, 2019, 18:56

Thanks for that.

So it's wanting me to change the units of the nut file essentially.
I wasn't aware the units of that had to change from incompressible to compressible flow?
How did you figure out it was nut that needed changing? very interesting...

Bdew8556 · August 20, 2019, 20:05

Interestingly...

After changing the units of the nut file the error reoccurs:

Creating field kinetic energy K

Courant Number mean: 0.00020326 max: 248.728

--> FOAM FATAL ERROR:
Different dimensions for =
dimensions : [1 -1 -1 0 0 0 0] = [0 2 -1 0 0 0 0]

From function bool Foam::dimensionSet:

perator=(const Foam::dimensionSet&) const
in file dimensionSet/dimensionSet.C at line 171.

FOAM aborting

boundary93 · August 21, 2019, 03:31

Just because of the units, but I was wrong. You have to change the pressure units when you change from incompressible to compressible to you have to check these.

Bdew8556 · August 21, 2019, 19:28

Yeah I already changed them.
Just to be certain what units for 'p' and 'p_rgh' would you be using?

boundary93 · August 22, 2019, 03:16

p and p_rgh share the same units:

[1 -1 -2 0 0 0 0];

Bdew8556 · August 22, 2019, 19:36

yep. thats what i've got them set as. hmmm.... seems like ive missed something else then.

boundary93 · August 26, 2019, 03:19

You should look at a tutorial and then compare all the units to yours. Including the thermophysical Properties.

Bdew8556 · August 26, 2019, 22:36

Made a breakthrough of sorts.
Looks like it's "alphat" that needed it's units changed.
It runs now. Whether the values I've chosen are physical or not we'll have to see but I've gotten over that issue.

boundary93 · August 27, 2019, 03:30

If you do RANS you should use a wallfunction for alphat with a turbulent Prandlt of 0.85, but if you do a LES with a fine grid it doesnt really matter in my experience.

Edit:
I just saw that you are doing LES, so forget about the RANS

August 20, 2019, 01:30	LES diesel jet	#1
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	Hi guys, I'm trying to simulate a diesel jet using LES. I'm trying to run compressibleMultiInterFoam. I think I'm getting close but I keep getting this error: Creating field kinetic energy K Courant Number mean: 0.0020326 max: 2487.28 --> FOAM FATAL ERROR: Different dimensions for = dimensions : [0 2 -1 0 0 0 0] = [1 -1 -1 0 0 0 0] From function bool Foam::dimensionSet:perator=(const Foam::dimensionSet&) const in file dimensionSet/dimensionSet.C at line 171. FOAM aborting Any thoughts???

August 20, 2019, 20:05		#6
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	Interestingly... After changing the units of the nut file the error reoccurs: Creating field kinetic energy K Courant Number mean: 0.00020326 max: 248.728 --> FOAM FATAL ERROR: Different dimensions for = dimensions : [1 -1 -1 0 0 0 0] = [0 2 -1 0 0 0 0] From function bool Foam::dimensionSet:perator=(const Foam::dimensionSet&) const in file dimensionSet/dimensionSet.C at line 171. FOAM aborting

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August 20, 2019, 04:04		#2
boundary93 New Member Adam Join Date: Jan 2019 Posts: 21 Rep Power: 7	Wrong unit change it the way the solver already told you

August 20, 2019, 04:07		#3
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	Thanks. What file do I need to change though??

August 20, 2019, 08:29		#4
boundary93 New Member Adam Join Date: Jan 2019 Posts: 21 Rep Power: 7	It looks like the "nut" file

August 20, 2019, 18:56		#5
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	Thanks for that. So it's wanting me to change the units of the nut file essentially. I wasn't aware the units of that had to change from incompressible to compressible flow? How did you figure out it was nut that needed changing? very interesting...

August 21, 2019, 03:31		#7
boundary93 New Member Adam Join Date: Jan 2019 Posts: 21 Rep Power: 7	Just because of the units, but I was wrong. You have to change the pressure units when you change from incompressible to compressible to you have to check these.

August 21, 2019, 19:28		#8
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	Yeah I already changed them. Just to be certain what units for 'p' and 'p_rgh' would you be using?

August 22, 2019, 03:16		#9
boundary93 New Member Adam Join Date: Jan 2019 Posts: 21 Rep Power: 7	p and p_rgh share the same units: [1 -1 -2 0 0 0 0];

August 22, 2019, 19:36		#10
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	yep. thats what i've got them set as. hmmm.... seems like ive missed something else then.

August 26, 2019, 03:19		#11
boundary93 New Member Adam Join Date: Jan 2019 Posts: 21 Rep Power: 7	You should look at a tutorial and then compare all the units to yours. Including the thermophysical Properties.

August 26, 2019, 22:36		#12
Bdew8556 Senior Member Brett Join Date: May 2013 Posts: 212 Rep Power: 13	Made a breakthrough of sorts. Looks like it's "alphat" that needed it's units changed. It runs now. Whether the values I've chosen are physical or not we'll have to see but I've gotten over that issue.

August 27, 2019, 03:30		#13
boundary93 New Member Adam Join Date: Jan 2019 Posts: 21 Rep Power: 7	If you do RANS you should use a wallfunction for alphat with a turbulent Prandlt of 0.85, but if you do a LES with a fine grid it doesnt really matter in my experience. Edit: I just saw that you are doing LES, so forget about the RANS