# How to define inlet velocity in 45 degrees from the inlet ?

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 July 14, 2020, 12:46 How to define inlet velocity in 45 degrees from the inlet ? #1 New Member   Kaboka Join Date: Dec 2019 Posts: 18 Rep Power: 5 Hello, I would like to define a velocity inlet in 45-degree angle for my quenching multiphase flow (water and air) case in 2D. I have tried to give the axial and radial velocity to inbuilt system, however it does not give me the exact solution. Could anyone help me about it? Do I have to add a UDF file or is there any other tricks you could recommend? Following pictures are my actual case and the velocity vector that I want: https://imgur.com/bSpbkGc https://imgur.com/ixaruoy Thanks in advance Bora

July 16, 2020, 15:28
#2
Member

Guven Nergiz
Join Date: Jul 2020
Location: Turkey
Posts: 49
Rep Power: 5
Hi Bora,
I am not sure but;
First of all, you need to divide the inlet section into two parts (from middle ofc). Then define the direction vectors and speed inputs one by one. Like in the screenshot below (in this coordinate system your velocity vectors can be X=1/Y=1/Z=0 and X=-1/Y=1/Z=0).
I hope that this can be a solution of your problem.
Best regards,
Güven
Attached Images
 velocity-inlet.JPG (57.8 KB, 43 views)

July 20, 2020, 07:50
#3
New Member

Kaboka
Join Date: Dec 2019
Posts: 18
Rep Power: 5
Quote:
 Originally Posted by Guvennergiz Hi Bora, I am not sure but; First of all, you need to divide the inlet section into two parts (from middle ofc). Then define the direction vectors and speed inputs one by one. Like in the screenshot below (in this coordinate system your velocity vectors can be X=1/Y=1/Z=0 and X=-1/Y=1/Z=0). I hope that this can be a solution of your problem. Best regards, Güven
Hi Güven,

Thanks for your answer, as my case is a 2D axisymmetric I don't have a coordinate system section in velocity window. I need an conical velocity profile which has a 45 degrees angles. I tried the following method but it doesn't give me a good solution. I'd be appreciated if you have any idea about that situation.

Bests.
Bora
Attached Images

 July 21, 2020, 02:40 #4 Senior Member   Alexander Join Date: Apr 2013 Posts: 2,345 Rep Power: 33 axial^2 radial^2 component together should give you 1 also you can use other reference frame, not absolute __________________ best regards ****************************** press LIKE if this message was helpful

July 22, 2020, 08:13
#5
New Member

Kaboka
Join Date: Dec 2019
Posts: 18
Rep Power: 5
Hi AlexanderZ,

Thanks for your advice but that didn't work. However, I found a way to define both axial and radial velocity with a Udf code individually. In Fluent, velocity vectors look good as you can see in the attachments, but when I load results to the CFD_Post it does not give the good conical spray nozzle shape. Do you have any idea what is the reason of this problem?

Bests,
Bora
Attached Images
 Inkedradialaxial_UDF_LI.jpg (69.9 KB, 31 views) time_0.1sc.png (45.3 KB, 25 views) time_0.005sc.png (46.7 KB, 20 views)
Attached Files
 radial.c (301 Bytes, 16 views) axial.c (305 Bytes, 7 views)

July 22, 2020, 08:54
#6
Member

Guven Nergiz
Join Date: Jul 2020
Location: Turkey
Posts: 49
Rep Power: 5
Quote:
 Originally Posted by kaboka Hi AlexanderZ, Thanks for your advice but that didn't work. However, I found a way to define both axial and radial velocity with a Udf code individually. In Fluent, velocity vectors look good as you can see in the attachments, but when I load results to the CFD_Post it does not give the good conical spray nozzle shape. Do you have any idea what is the reason of this problem? Bests, Bora
Hi Bora,
Maybe you should run your case a bit longer to get fully developed region?
Best regards,
Güven

August 5, 2020, 15:38
#7
New Member

Kaboka
Join Date: Dec 2019
Posts: 18
Rep Power: 5
Quote:
 Originally Posted by Guvennergiz Hi Bora, Glad to hear you solved your main problem. Maybe you should run your case a bit longer to get fully developed region? Best regards, Güven
Hi Güven,

Unfortunatelly I have tried that as well but that was not the case. I am still trying to find the best solution here. If anyone have any idea about that I'd be very appreciated. In order to make it clear I add one more volume fraction picture on CFD-Post and what I want it really. Thanks in advance.

Bests,
Bora
Attached Images
 Picture1.jpg (9.2 KB, 19 views) Picture2.JPG (25.9 KB, 14 views)

 Tags ansys, axial, cfd, fluent, radial velocity