Learning Forum

[Mohamed Salman Mohamed Haniff]

Hi, 

I am trying to measure the inlet and outlet velocity of a bent pipe placed underwater; I created an enclosure and subtracted the pipe from the enclosure using a boolean.

However, in the results, the flow seems to go past this pipe and not through it. 

Is there any way to make the fluid flow through the pipe, and how can the inlet and outlet be defined in the pipe to measure the velocity at the place. 

I have been trying for a long time; any help would be highly appreciated. 

[Rob]

If you subtract the pipe volume you're left with a void, so no flow can pass though the space. If you subtract+retain, and then use share topology you'll have two connected volumes. You then need to label (named selection) the wall as a wall, and the pipe inlet & outlet as interior. Do not use inlet/outlet or in/out as the two interior labels as those will automatically assign a boundary type in Fluent. 

[Mohamed Salman Mohamed Haniff]

 

Hi Rob,

Thank you for your reply. May I know how to share the topology between the two bodies in the design modeler?

I tried as shown below, but I got the same results with flow going past the pipe. 

 

[Rob]

In DM create a multibody part. No need for the share topo command either, that's for SpaceClaim and Discovery. 

[Kelsey O'Donnell]

Rob, how do you subtract and retain in spaceclaim/discovery? Also is there a limit to the number of objects you can do this with? I want to create a 3D bed of "mussels" that are tiny pumps and surround them in a fluid domain to simulate how their pumping impacts flow. 

[Rob]

It's the "Combine" tool. It'll be covered in the tutorials under Help on the software. You'll need to check how it handles multiple objects, I think it's a case of clicking each one but I tend to focus more on the solver side. 

How big a domain are you looking at? Ie is the mussel pumping sufficient to do much? 

[Kelsey O'Donnell]

Hi Rob, 

Thank you for that. The domain would be about 2 m by 0.5 m and the bed itself would be around 1 m by 0.5 m, the question I am partially trying to answer is how much of an impact the mussel pumping has on the hydrodynamics and mixing processes. Each mussel outlet would have a velocity of around 1-2 cm/s and I am looking at very slow (less than 5 cm/s) ambient flows. 

[Rob]

Please can you put a new thread in as it'll be easier for the search tools in future. 

There are a few models/options you may want to explore in Fluent.