Water flow in a spiral like tube
 

Hi everybody,
I'm trying to simulate a flow of water in a tube with 3 U bends. Please check the below figure.

Why is the liquid flows outside the steel tube near the first U bend?

Maybe a hole in your geometry? Have you checked it to be closed before meshing? Is your mesh resolution capable to catch the U-bend accordingly or could it intersect with the wrong surface when taking the interface tolerance into account?

so do you think a finer mesh size will solve the problem?

Link to sim file: https://docs.google.com/file/d/0B43E...8ya3JIdWc/edit

Thank you

Can't access the file. You need to set some permissions.

Hope you can download the file now

Thank you

Got it, I'm looking on it right now.

Any idea on whats going on?

Thank you

Is the problem with the streamline generation? Looks like the time step is too large.

Uuupps, sorry. Totally forgot to write an answer.
The issue is not the streamline generation, it's the crap model setup (sorry, I have to say that). The air box and the solid share partly the same volume and I think the interfaces are not set right.
I'm sorry I don't have a picture right now. I will post it within the next one or two days. I promise!

Okay, now I've got the pictures. The first two pictures are showing your setup: The air region (blue) overlays the steel region (green). Also the interfaces are not right. The water region touches the inner wall of the steel region, so far no issue. But also the air region touches the inner wall of the steel region. This is no proper setup. The air region should touch the outer wall of the steel region.
This is causing an interface between water region and the air region, causing the water to pass "through" the steel.

The third pictures shows the setup how it should look like: Outer wall of the water region touches the inner wall of the steel region, the outer wall of the steel region touches the inner wall of the air region.

You need to subtract the steel region from the air region and create new interfaces.

I created a straight tube with interfaces.
Is this the correct way to do it?

https://docs.google.com/open?id=0B43...jU1ZXBYR09HOWM

Thank you for time