Dear Bianca

At first it is needed to know what kind of wind profile do you use? If you use a simple velocity inlet as your inlet B.C, so simply you need to put X and Y or Z (in 3D circumstances) direction by as you said Magnitude and direction specification method.

For this purpose, in X component of flow direction put the value of Cosine (A) and in Y component of flow direction put the value of Sine (A), where A is the angle of free stream regards to X and Y direction.

Hey Mahdi, 

At first thank you so much. You really helped me!!!! Thank you !!

About your question:

- I am using the wind profile with coordinates X,Y,Z because my domain is 3D.

I will try excatly what you said.

Hi Bianca,

I am assuming you are simulating wind effects on tall buildings and of course there is atmospheric bounday layer in the inlet. Am I right? I worked on similar topics with Fluent before. To mimic the velocity profile in the inlet you can use an UDF. I can also recommend some articles about this topic. If I find the UDF file , I also can send it.

Hi Tufan,

Thank you for your answer.

Yes, you are right! I am working with atmospheric boundary layer. I am trying to set more or less 37 point that each point there is a direction, hieght and module (Velocity).

I really dont know nothing about UDF.

That's sound great! Can you send me a email with everything about this topic and, for sure, I will be grateful with this.

My email I will send you for massage.

Thank you a lot.

You could go through the FLUENT UDF Manual. In that, on page 544, they have given an example of how to introduce a parabolic inlet velocity profile. You could change it to the profile you desire. Hope this helps. Here's the manual. There are quite a number of examples you can try out too. Wish I could help you more, but I am new to it too.

 Hi , Fahd.

I am studing this subjects. I really dont know nothing about fluent UDF yet. But there is something that I know. My wind profile is a natural. I take the wind profile directly from environment. And I am not sure if this UDF can help me. But it is like I told you... I am a new in this  subject. 

I will study more about fluent UDF and try to understand. For before that, try to use this on my reaserch. 

Thank you a lot. I also will use this atarchament. 

Bianca Hulle

Hello , 

very interesting topic , i started using fluent early month ago , very good questiion that i benefited from . I am following you for further studies.

Thanks  

Sorry for delay

Your case is not a simple velocity inlet as I asked before. You are as you said simulating the ABL (atmospheric boundary layer) which not only needs to care about the equation of wind profile, but  also you need to care about turbulence model to verify your solution.

In the case of wind profile I suggest to study about two equation called log law equation and power law equation.

Your 37 point experience data can be simulated with these equations.

About UDF (User defined function), this is a C programming code written to be compiled in fluent to introduce costume conditions. In your case, You need to develop or create a C code using Log law equation to introduce the ABL boundary condition and according to your B.C you need to use appropriate turbulence model or write an UDF code for that also.

Hi Mahdi Hozhabri Namin ,

No problem,

Yes, I am simulating the ABL, in real conditions. In the other question, someone suggested divide the inlet. I think it is a great ideia. If you want,, see in this link:

https://www.researchgate.net/post/How_to_set_the_Velocity_Magnitude_and_Direction_in_FLUENT