How to form hydraulic jump at specified location with interFoam
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hello everyone,
I'm simulating a free hydraulic jump with InterFoam. In the laboratory model, the jump occurs at a distance of one meter from the gate, but in the simulation, despite changes in various parameters such as mesh and inlet velocity, boundary condition and etc, this does not happen and the jump occurs immediately after the gate. Can anyone help me? I will appreciate that, I attached the geometry of the laboratory model. In the geometry of the simulation, I've ignored the tank. |
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A first suggestion is to put a weir at the downstream section, with the height necessary to produce the critical height above it. The calculation of the critical height is an exact measure (not its location, though) so you can use that as a reference on how good the simulation is running, in terms of turbulence/physics. From there, it's a matter of patience: you need to test turbulence models and different schemes for the divergence operator. Excessive dissipation will produce spurious recirculations on the bottom of the channel, below the roller. Be particularly mindful of using "Bouyancy aware" URANS models. Wall models also play an important role here, particularly with the location of the jump. IMPORTANT NOTE: Inertial-scale processes happen on the cross normal direction of the jump, hence it is necessary to run 3D (or 2.5D) simulations. In 2D you'll see spurious behaviour and a Richardson Analysis will show instability. You can try it out... Question: What version/flavor of OpenFOAM you're using? |
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A URANS classic hydraulic jump at Fr = 8.5. On top an instantaneous snapshot, and on the bottom the mean fields. https://imgur.com/NnsyGNt |
This may be associated with outflow boundary conditions since higher tail water depth moves the hydraulic jump to the control structure.
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[QUOTE=Santiago;811754]
thank you for replying, I am using OpenFOAM 8, One suggestion for me was to use " Interisofoam" at OpenFoam 18.12 because the "interFoam" does not work well for hydraulic jumping and also to avoid bed roughness. Do you have an opinion on this? |
[QUOTE=luccy;812023]
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MY SUGGESTION: Choose a "flavor" of OpenFOAM, and stick to it. |
Also recommend you to choose right turbulent model. I performed this simulation with interFoam few moths ago and different turbulent model gives different results. For me most stable was kEpsilon. Also consider 2.5D and 3D approach. There are tons of articles around web.
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a question about the link you shared
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https://imgur.com/NnsyGNt Whose simulation was this? was it yours? |
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thank you |
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Anyway, I assume you read my previous post where I talked about the importance of over-dissipation and the reason for the dremple. But if you think the problem is with your BCs, then of course I can show you mine. U: Code:
boundaryField Code:
boundaryField Code:
wallsBottom |
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I have another question about the inlet conditions. I want to set the boundary conditions as a velocity profile at the inlet, but I do not have access to the equation in three dimensions. Can you help with that? Also, in my open foam, there is no powerLawVelocity condition. Please pay attention to the attached photo. |
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I have another question about the inlet conditions. I want to set the boundary conditions as a velocity profile at the inlet, but I do not have access to the equation in three dimensions. Can you help with that? Also, in my open foam, there is no powerLawVelocity condition. Please pay attention to the attached photo. |
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