Fluxes report on results

BlackHeartInertia · June 18, 2017, 22:54

Why when I calculate mass fluxes imbalance it says 1exp-5 and if I proceed with more iterations it change to 1exp-3?

Ty

BlnPhoenix · June 19, 2017, 09:00

Do you have re-circulations from outlet?

BlackHeartInertia · June 19, 2017, 18:26

20170619_142842.jpeg 20170619_181554.jpeg

I have a zone call momentum source that produce a recirculation zone (fuente mom). In my model I have two recirculation zones but in different places. So it takes air from the botton and reinject the same amount of air at top ...like a centrifugal fan.

In one of the photos that I have posted here, the second source gives a postive value and the flux imbalance is 1exp-6. Then the flux imbalance past from positive to negative to a value like -0.001.

I dont understand. Do you have an idea of how can I explain this? Anything

BlnPhoenix · June 20, 2017, 02:31

I don't quit understand what i'm looking at in the pictures. Are these mass fluxes?

How can you have mass flux from an interior? I dont understand your setup..

BlackHeartInertia · June 20, 2017, 09:36

That values are in kg/s.
There is mass fluxes but the source is in N/m3 so is doesnt counts as inlet or outlet it is just for moving air though it.

The mass imbalance is computed with
Inlets: "velocity_inlet_q1", "velocity_inlet_q2"
And
Outlets: "pressure_outlet"

Sent from my SM-G570M using CFD Online Forum mobile app

BlnPhoenix · June 21, 2017, 08:18

Unfortunatly i'm not an expert with compressible medium you are using.
Your mass balance seems quite good still. So i would monitor this value with further iterations. In general mass imbalance should get smaller with better convergence, so in reverse one could assume, that you're currently not converging correctly. But i would monitor more values to judge convergence here, one of the values being mass imbalance. Are your momentum sources time dependet or constant? Your are simulating steady state, right?

June 18, 2017, 22:54	Fluxes report on results	#1
BlackHeartInertia New Member yardena jodeck Join Date: May 2017 Posts: 29 Rep Power: 10	Why when I calculate mass fluxes imbalance it says 1exp-5 and if I proceed with more iterations it change to 1exp-3? Ty

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
OpenFOAM - Validation of Results	Ahmed	OpenFOAM Running, Solving & CFD	10	May 13, 2018 18:28
Oscillating Airfoil Poor Results at High k (reduced frequency)	dancfd	OpenFOAM Running, Solving & CFD	3	November 4, 2013 08:32
Creating a tool to interpolate results	Luis Batista	OpenFOAM Running, Solving & CFD	2	April 11, 2013 08:15
Transient Run - Output "Time" in partial results?	evcelica	CFX	2	May 16, 2012 21:36
wind tunnel results vs fluent	pixie	Main CFD Forum	1	August 20, 2009 08:02

June 19, 2017, 09:00		#2
BlnPhoenix Senior Member Join Date: Aug 2014 Location: Germany Posts: 292 Rep Power: 14	Do you have re-circulations from outlet?

June 19, 2017, 18:26		#3
BlackHeartInertia New Member yardena jodeck Join Date: May 2017 Posts: 29 Rep Power: 10	20170619_142842.jpeg 20170619_181554.jpeg I have a zone call momentum source that produce a recirculation zone (fuente mom). In my model I have two recirculation zones but in different places. So it takes air from the botton and reinject the same amount of air at top ...like a centrifugal fan. In one of the photos that I have posted here, the second source gives a postive value and the flux imbalance is 1exp-6. Then the flux imbalance past from positive to negative to a value like -0.001. I dont understand. Do you have an idea of how can I explain this? Anything

June 20, 2017, 02:31		#4
BlnPhoenix Senior Member Join Date: Aug 2014 Location: Germany Posts: 292 Rep Power: 14	I don't quit understand what i'm looking at in the pictures. Are these mass fluxes? How can you have mass flux from an interior? I dont understand your setup..

June 20, 2017, 09:36		#5
BlackHeartInertia New Member yardena jodeck Join Date: May 2017 Posts: 29 Rep Power: 10	That values are in kg/s. There is mass fluxes but the source is in N/m3 so is doesnt counts as inlet or outlet it is just for moving air though it. The mass imbalance is computed with Inlets: "velocity_inlet_q1", "velocity_inlet_q2" And Outlets: "pressure_outlet" Sent from my SM-G570M using CFD Online Forum mobile app

June 21, 2017, 08:18		#6
BlnPhoenix Senior Member Join Date: Aug 2014 Location: Germany Posts: 292 Rep Power: 14	Unfortunatly i'm not an expert with compressible medium you are using. Your mass balance seems quite good still. So i would monitor this value with further iterations. In general mass imbalance should get smaller with better convergence, so in reverse one could assume, that you're currently not converging correctly. But i would monitor more values to judge convergence here, one of the values being mass imbalance. Are your momentum sources time dependet or constant? Your are simulating steady state, right?