Initializing fluid level on VOF model

October 30, 2008, 13:55

I'm trying to model the flow through a trough distributor, with both the top and bottom open to atmosphere. Liquid enters through a downspout. I know the theoretical average surface height, and I would like to use this as an ititial condition. If I try to break the fluid domain into 2 zones (1 for liquid, 1 for air with the interface at the expected surface level) the solver fails with Error: Floating point error: invalid number. This happens regardless of whether i'm using the VOF model or a single phase. Do you have any recommendations for initializing the domain, or a way around this error? Thanks.

October 30, 2008, 15:27

You can do this in 3 steps: 1) Initialise the domain with VOF = 0 for liquid. 2) Go to Adapt->Region and mark the region that is full of liquids using coordinates. 2) Go to Solve->Initialise->Patch and patch the region you marked in step 2 with liquid VOF = 1

November 4, 2008, 17:20

Thanks CDE. That seems to help.

alven299 · July 3, 2009, 02:05

Quote:

Originally Posted by CDE
;154423

You can do this in 3 steps: 1) Initialise the domain with VOF = 0 for liquid. 2) Go to Adapt->Region and mark the region that is full of liquids using coordinates. 2) Go to Solve->Initialise->Patch and patch the region you marked in step 2 with liquid VOF = 1

Hi CDE, how do you check whether the VOF=0 for liquid upon initializing? Thank you.

-mAx- · July 3, 2009, 03:04

you can check your initialization by displaying the contour of vof before starting to iterate
It should match the value you gave in solve/initialize

alven299 · July 3, 2009, 03:45

thank you very much, at least I have a bit of idea on wat is going on in VOF now

October 30, 2008, 13:55	Initializing fluid level on VOF model	#1
Daniel Guest Posts: n/a	I'm trying to model the flow through a trough distributor, with both the top and bottom open to atmosphere. Liquid enters through a downspout. I know the theoretical average surface height, and I would like to use this as an ititial condition. If I try to break the fluid domain into 2 zones (1 for liquid, 1 for air with the interface at the expected surface level) the solver fails with Error: Floating point error: invalid number. This happens regardless of whether i'm using the VOF model or a single phase. Do you have any recommendations for initializing the domain, or a way around this error? Thanks.

October 30, 2008, 15:27	Re: Initializing fluid level on VOF model	#2
CDE Guest Posts: n/a	You can do this in 3 steps: 1) Initialise the domain with VOF = 0 for liquid. 2) Go to Adapt->Region and mark the region that is full of liquids using coordinates. 2) Go to Solve->Initialise->Patch and patch the region you marked in step 2 with liquid VOF = 1

November 4, 2008, 17:20	Re: Initializing fluid level on VOF model	#3
Daniel Guest Posts: n/a	Thanks CDE. That seems to help.

July 3, 2009, 03:04		#5
-mAx- Super Moderator Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,297 Rep Power: 41	you can check your initialization by displaying the contour of vof before starting to iterate It should match the value you gave in solve/initialize __________________ In memory of my friend Hervé: CFD engineer & freerider

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July 3, 2009, 03:45		#6
alven299 New Member alven Join Date: Mar 2009 Location: Malaysia Posts: 25 Blog Entries: 1 Rep Power: 17	thank you very much, at least I have a bit of idea on wat is going on in VOF now