Dynamic addition of objects at inlet

phandy · May 26, 2015, 13:24

Hello, experts of the cfd world.

I would like to set up a case where solid objects (clones of a model) are injected at some interval near the inlet (or come through the inlet). Is this even possible with the way that openfoam is set up?

My thought process with this is that perhaps simulation time could be cut down rather than having some sort of hopper.

Nicole · May 27, 2015, 06:33

Hi Paul,

This sounds like a very interesting problem. Please could you give some more info?

A colleague of mine has managed to get solids to "flow" through his domain by adding a convective term to a solid solver, but I can't figure out if this is something you want to do?

Regards,
Nicole

phandy · May 27, 2015, 09:45

Hi, Nicole.

What your colleague has done sounds interesting. In the initial condition of the case, are all of the solids present? If so, by how much does that effect the simulation time?

Essentially, I am trying to simulate solid objects in a moving liquid as they exit a pipe and enter a separate reservoir

In my ideal simulation, a solid would inject at the inlet of the domain at a defined time interval, as if a clone of the original object is placed at the object's initial location; and, if possible, exit the domain at the outlet. If it was placed just outside of the domain and comes through it at that time, I think that would be most interesting.

Or is this the kind of thing that the Foam-Extend multisolver can do, perhaps in junction with your colleague's solver?

Nicole · May 27, 2015, 09:59

Hi Paul,

We have definitely passed outside of my limited CFD experience, but I think you may need to use more of a Lagrangian technique, such as Smoothed Particle Hydrodynamics (SPH), take a look at https://www.youtube.com/watch?v=EcsX0x-YcAw, or a DEM simulation. OpenFOAM doesn't do either of these as far as I know. LIGGGHTS is an open source DEM solver that I have heard of.

My colleague's "solid" is a bed that moves on a belt through the computation domain, so the volume that the solid region occupies is fixed and does not move.

I really am just guessing, but maybe you could get your solid objects to work using a multiphase solver, if you wanted to use OpenFOAM?

Good luck! I look forward to hearing what you get to work!

May 26, 2015, 13:24	Dynamic addition of objects at inlet	#1
phandy New Member Paul Handy Join Date: Sep 2014 Location: Idaho, USA Posts: 21 Rep Power: 11	Hello, experts of the cfd world. I would like to set up a case where solid objects (clones of a model) are injected at some interval near the inlet (or come through the inlet). Is this even possible with the way that openfoam is set up? My thought process with this is that perhaps simulation time could be cut down rather than having some sort of hopper.

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May 27, 2015, 06:33		#2
Nicole Member Nicole Andrew Join Date: Sep 2014 Location: Pretoria, South Africa Posts: 58 Rep Power: 11	Hi Paul, This sounds like a very interesting problem. Please could you give some more info? A colleague of mine has managed to get solids to "flow" through his domain by adding a convective term to a solid solver, but I can't figure out if this is something you want to do? Regards, Nicole

May 27, 2015, 09:45		#3
phandy New Member Paul Handy Join Date: Sep 2014 Location: Idaho, USA Posts: 21 Rep Power: 11	Hi, Nicole. What your colleague has done sounds interesting. In the initial condition of the case, are all of the solids present? If so, by how much does that effect the simulation time? Essentially, I am trying to simulate solid objects in a moving liquid as they exit a pipe and enter a separate reservoir In my ideal simulation, a solid would inject at the inlet of the domain at a defined time interval, as if a clone of the original object is placed at the object's initial location; and, if possible, exit the domain at the outlet. If it was placed just outside of the domain and comes through it at that time, I think that would be most interesting. Or is this the kind of thing that the Foam-Extend multisolver can do, perhaps in junction with your colleague's solver?

May 27, 2015, 09:59		#4
Nicole Member Nicole Andrew Join Date: Sep 2014 Location: Pretoria, South Africa Posts: 58 Rep Power: 11	Hi Paul, We have definitely passed outside of my limited CFD experience, but I think you may need to use more of a Lagrangian technique, such as Smoothed Particle Hydrodynamics (SPH), take a look at https://www.youtube.com/watch?v=EcsX0x-YcAw, or a DEM simulation. OpenFOAM doesn't do either of these as far as I know. LIGGGHTS is an open source DEM solver that I have heard of. My colleague's "solid" is a bed that moves on a belt through the computation domain, so the volume that the solid region occupies is fixed and does not move. I really am just guessing, but maybe you could get your solid objects to work using a multiphase solver, if you wanted to use OpenFOAM? Good luck! I look forward to hearing what you get to work!