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#1 |
New Member
Emad S
Join Date: Dec 2021
Posts: 14
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Hi all.
Since we define parcels as a number of particles, why do we have to define clouds? Thanks Emad |
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#2 |
New Member
Emad S
Join Date: Dec 2021
Posts: 14
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Also
- In discrete phase method (DPM) the forces are solved for parcels or particles or cloud in dpmfoam? - if nParticle=1 are dpm and dem exactly the same? |
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#3 |
New Member
Emad S
Join Date: Dec 2021
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And anothe question:
I have defined stick parameter between the particles and the wall. When a particle sticks to a wall the whole cloud stickes or the parcel including that particle or just the individual particle? |
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#4 | |
Senior Member
Josh Williams
Join Date: Feb 2021
Location: Scotland
Posts: 114
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Quote:
Yes, if number of particles in parcel is one, then DPM = DEM. Otherwise, it is same as 'coarse DEM'. |
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#5 | |
New Member
Emad S
Join Date: Dec 2021
Posts: 14
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Quote:
How the diameter of the cloud is defined? And do parcels leave a cloud? |
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#6 | |
Senior Member
Josh Williams
Join Date: Feb 2021
Location: Scotland
Posts: 114
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Quote:
Parcels do not leave a cloud. Particles do not leave a parcel (I think). |
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#7 | |
New Member
Emad S
Join Date: Dec 2021
Posts: 14
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Quote:
If a cloud does not have a diameter then the forces like drag force which is a function of diameter is calculated for each parcel if it has a diameter, otherwise calculation is conducted over each particle! What is the rationale behind defining clouds and parcels then?! We are just doing dem imo! |
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#8 | |
Senior Member
Josh Williams
Join Date: Feb 2021
Location: Scotland
Posts: 114
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Quote:
In OpenFOAM, you define the diameter of one particle. You define how many particles are in one parcel. You can calculate the forces using the particle diameter. Lets say you use parcel approach like MPPIC, you calculate drag based on particle diameter (p.d() in the source code). Then you apply some collision kernel (like Harris-Crighton in tutorials), which is based on the number of parcels in each cell, the number of particles in a parcel, and the individual particle diameter. If you have further difficulty, I suggest you review the source code Code:
cd $FOAM_SRC/lagrangian/intermediate/parcels/Templates/KinematicCloud Code:
cd $FOAM_SRC/lagrangian/intermediate/submodels/Kinematic/ParticleForces/Drag/SphereDrag Last edited by joshwilliams; August 17, 2022 at 11:50. |
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#9 |
New Member
Emad S
Join Date: Dec 2021
Posts: 14
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Thanks!
This was very illustrative. |
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