Dear Amir, may I suggest to send a query to Dr. Sauro Succi ? He is really an expert in this field that he pioneered and he is also very helpful. Definitely he will be able to help you. Marco

Dear Ayurzana,

Hi

Actually I am using these BCs But it still flow wont pass the outlet and its look like the outlet is like a wall and flow will bounce back into the channel.

Dear Ayurzana,

Hi

It seems i found the source of my problem. For streaming I used all of my domain grid, which leads to this problem. When I removed the last node in x direction from my stream function, program ran well and I got my results.

Is this OK?

Shouldn't all of domain nodes be in the function?

By the way I use FORTRAN too, and I linked my stream function.

Can you check it?

Thank you

http://pastebin.com/x5GXy83C

Dear Ayurzana,

Hi

Thank you very much.

So Basically I have to run stream function in all of my domain except the first and last nodes in each direction?

Dear Ayurzana,

Hi

Thank you very much.

There is another thing that bothers me.

You see, in Zhu and He boundary conditions, they use these formulas (Pic 1) for North velocity boundary. But when i use them solver will give me nan or very large numbers.

On the other hand when i use A.A Mohammad codes which he use these formulas (Pic 2) solver will work perfectly.

Can you give me some hints about this?

Thanks in advance for your help.

Sorry it seems i forgot to mention that these are for Lid Driven Cavity.

My problem is 1/6 coefficient of these terms. shouldn't they have to be 1/2? 

If this is correct then shouldn't they had same sign too?

for LDC we have horizontal velocity at north boundary, so we should have 1/2*rho*u terms not 1/6*rho*v terms.

Thank you very much.

By the way, Do you know good reference for learning immersed boundary method?

Thank you very much.

Finally, I can understand the problem :).

I am going to simulate a simple flow over a cylinder in channel.

By the way, Do you know where i can find moving wall boundary conditions?