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#1 |
New Member
Join Date: Nov 2019
Posts: 24
Rep Power: 6 ![]() |
Hello everyone,
I am a new openFoam user and i am trying to figure out which solver should I use for my hydraulic applications. In particular, I need to simulate a system of interconnected culverts( i.e. closed conduits of rectangular shape) where water flows at a specified inlet flow rate. The water in these closed channels can be pressurised or free surface (i.e. the water level can either be below the culverts' soffitt or reaching it determining a pressure increase). I want to run 3D steady-state turbulent simulations with uncompressible newtonian fluid. I don't know if I have to work with a single phase fluid (water) or if instead I have to work with 2 fluids (water +air) because the channel could be partially filled by water and air on the top. The simpleFoam and the interFoam seemed to meet my needs (although I don't know which one to prefer in my case) but I have other requirements in terms of boundary conditions. In fact, these solvers require velocity and pressure at the boundaries, while I need to set a water flow rate (m³/s) at the inlet and a constant water level at the downstream boundary (outlet). Also, in the simpleFoam I could not find where to specify the gravity vector which is fundamental for my applications (water moves downstream due to gravity). Can anyone assist me with this? Is there any tutorial similar to my case? Apologies if my question is confusing but I am confused myself. Thank you, Nic |
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#2 | |
Super Moderator
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,711
Blog Entries: 6
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Hi Nic,
actually you answered your question yourself: Quote:
If you have partially filled shapes, you need to have a 2-phase solver (actually you can also work with one and dynamic meshes but this would be too much here). So interFoam is the one you should start if you have partially filled domains (water + air as you mentioned). If you are interested in the steady-state condition, the LTS option would be nice for you.
__________________
Keep foaming, Tobias Holzmann |
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#3 |
New Member
Join Date: Nov 2019
Posts: 24
Rep Power: 6 ![]() |
Hi Tobias and thank you for your answer.
I am focusing on interFoam as i understood is the solver for my applications, but I couldn't find any tutorial or example where the inlet and outlet boundary conditions are the following: Inlet : constant or time dependent volumetric flow rate Outlet : constant or time dependent water level Do you know where can I find such an example or could you guide me on how to male this setup? Cheers, Nic |
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#4 | |
Senior Member
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 354
Rep Power: 15 ![]() |
Quote:
for the outlet, as you want to keep the water level you'll have to force a certain total pressure in the water column, while letting the pressure 'unrestricted' on the air side. A mixed (robin) condition is needed. The velocities can be inletOutlet, and alpha1 zeroGradient. |
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#5 |
New Member
Join Date: Nov 2019
Posts: 24
Rep Power: 6 ![]() |
Thank you Santiago.
That means that at the inlet i will have to set a constant velocity equal to the FlowRate/(Area x Alpha) ? Once the simulation will run, is there a way in ParaView to calculate the flow along a cutting plane to ensure that the inlet flow is correct? Do you have any example similar to my case? Thank you. Nic |
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#6 | |||
Senior Member
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 354
Rep Power: 15 ![]() |
Quote:
Quote:
Quote:
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#7 |
New Member
Join Date: Nov 2019
Posts: 24
Rep Power: 6 ![]() |
What is it "small"?
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#8 |
Senior Member
Santiago Lopez Castano
Join Date: Nov 2012
Posts: 354
Rep Power: 15 ![]() |
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#9 |
New Member
Join Date: Nov 2019
Posts: 24
Rep Power: 6 ![]() |
Thank you !
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Tags |
flow rate, solver, water |
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