complex water obstacle help

So i have a curvy object that i want to act as an obstacle for water, but i have not idea how to get it to work, what settings do i use?

Enable Fluid > Enable Obstacle

but the water does not fall down my half pipe shaped thing.

Ok, in that case, I think I need to refer you to one of the fluid tutorials. It is clear one of your settings is incorrect. http://www.blendernation.com/2006/01/21/fluid-simulation-in-blender/

You could also upload a blender file and I can take a look at it for you.

check your normals