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-   -   Flow rate (http://www.cfd-online.com/Forums/flow-3d/82887-flow-rate.html)

Sly787 December 8, 2010 11:35

Flow rate
 
Hi, I have to find how a flow rate changes in time.
I model my nozzle driven by pressure BC and I must insert a 2D plane, and the nozzle end, to control flow rate across this. I have to find a time-behavior of flow rate.
How can I do in Flow-3D?

MuxaB January 17, 2011 02:45

Quote:

Originally Posted by Sly787 (Post 286546)
Hi, I have to find how a flow rate changes in time.
I model my nozzle driven by pressure BC and I must insert a 2D plane, and the nozzle end, to control flow rate across this. I have to find a time-behavior of flow rate.
How can I do in Flow-3D?

Use a flux surface, which is a flat baffle with IBAF(1)=1. It will compute and output the total flow rate through it.

aginor January 17, 2011 20:49

i also have a similar problem. i can view the results from this baffle. where are they?

aginor January 17, 2011 20:59

this is my baffle. the result is always a zero. but i have flow throw this baffle.
nbafs=1, ifbaf(1)=1, bxl(1)=0., bxh(1)=0.5,
byl(1)=0., byh(1)=1., bzl(1)=0., bzh(1)=0.2, FPTITL(1) ='sxara',

JBurnham January 18, 2011 12:19

I think you have the baffle defined incorrectly. You've 'limited' min and max x's, y's, and z's, which would create a 3-D cube, but this is not how FLOW-3D interprets a baffle. You can keep two sets of the 'limiters' (byl, byh & bzl, bzh for example), remove the x-limiters, and specify one plane 'definition' in x in which the baffle appears (and is limited): bx = 0.25, for example. As you have it defined currently, FLOW-3D is probably just ignoring it during preprocessing. Check your preprocessor messages and errors.

MuxaB January 19, 2011 01:35

Quote:

Originally Posted by aginor (Post 290866)
i also have a similar problem. i can view the results from this baffle. where are they?

Once you open the flsgrf file, the results from a flux surface baffle will be in Probe > General history data catalog, along with all other mesh-independent quantities such as fluid volume and kinetic energy, as a function of time.


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