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-   -   Stratified environment (http://www.cfd-online.com/Forums/cfx/104934-stratified-environment.html)

HMR July 19, 2012 00:44

Stratified environment
 
Hi CFX Users,

I am simulating a case into a small rectangular box(length=width=1m, height=0.3m) open top, wall non-slip rigid insulated and bottom also insulated except the small nozle(r=0.005m) for injecting single phase water jet flow inside it. Newtonian stratified single phase fluid is considered in this box. From calculation, I put water jet velocity0.0343m/s and its temperature 298.64K. As stratified fluid stay in the box so every meter of height of the box temperature will chage N=8.155 K/m so i write an expression To=302.44-N* Z coordinate, and initializes it . Choose bouyancy and its temperature 300K from setup as this is a negative bouyancy case.

mesh sizes 3mm, time step 0.087 with 1.8million of mesh, I run this simulation for 400sec.
Everything fine , simulation finished well but the problem is jet flow penetration height inside this box is not long enough what we expected from previous investigations done by another people in fluent.

I do not understand what is happening. I tried in different way but no solutions i get till now.

If anybody give me any suggestion it will be a great help for me.Because around me knowbody actually know CFX.

Regards

HMR

ghorrocks July 19, 2012 06:08

Can you confirm that your temperature function just defines the intial condition? Obvious from there the air establishes its own temperature field in the simulation.

Have a look at this FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

HMR July 21, 2012 21:07

Hi Glenn,

Thanks for your reply. Yes I am trying to figure out the problem according to your advice.

Cheers

HMR

Felggv July 23, 2012 09:44

Attach some pictures of your results so ppl here can analyse.


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