Hi,
perhaps it would be useful to have a thread which lists meaningful working parameter combinations depending on the Fluid properties?
So anyone who wants to contribute something can add it to this thread...
At the end we could possibly create a flowchart...
Best Regards
Working Parameter Combinations
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- Posts: 113
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Re: Working Parameter Combinations
9mm Cartridge (Freecad 0.20.01_29410 (Git))
Fluid Properties:
Air
Physics model:
- Time: steady
- Flow: Single phase; incompressible; Viscous: yes
- Turbulance: laminar
Initialise Flow Field:
- Velocity: Potential Flow
- Pressure: Potential Flow
Mesh Parameters:
- Mesh Utility: cfmesh
- Base Element Size: 3mm
Mesh Refinement:
- Surface Refinement
- Relative Element Size: 0,1
- Refinement Thickness: 0,1mm
- Boundary Layers: no
Fluid Boundary:
-Inlet: Uniform Velocity; 800m/s for Ux
-Outlet: Static Pressure
-Wall: Slip inviscid (Frictionless Wall)
-Constraint: Symmetry
Mesh Results:
It is important to have a good value for the Base ELement Size because this value mainly determines the processing time of the solver. So it's best to keep it as small as possible to get a good result, but still keep it big enough that you can use the solver relatively quickly. So if you have a good value in this case 3mm than you should do Refinement because of this:
Meshresults without Refinement:
Meshresults with a Refinement of Relative Element Size: 0,5 and Refinement Thickness: 0,5mm
Meshresults with a Refinement of Relative Element Size: 0,1 and Refinement Thickness: 0,1mm
I didn't see much of a difference between with and without doing Boundarylayers. Maybe someone else can explain that.
So the Results in Paraview look like that:
Maybe someone has an idea for a more precise model or extensions that they would like to contribute based on this example.
Fluid Properties:
Air
Physics model:
- Time: steady
- Flow: Single phase; incompressible; Viscous: yes
- Turbulance: laminar
Initialise Flow Field:
- Velocity: Potential Flow
- Pressure: Potential Flow
Mesh Parameters:
- Mesh Utility: cfmesh
- Base Element Size: 3mm
Mesh Refinement:
- Surface Refinement
- Relative Element Size: 0,1
- Refinement Thickness: 0,1mm
- Boundary Layers: no
Fluid Boundary:
-Inlet: Uniform Velocity; 800m/s for Ux
-Outlet: Static Pressure
-Wall: Slip inviscid (Frictionless Wall)
-Constraint: Symmetry
Mesh Results:
It is important to have a good value for the Base ELement Size because this value mainly determines the processing time of the solver. So it's best to keep it as small as possible to get a good result, but still keep it big enough that you can use the solver relatively quickly. So if you have a good value in this case 3mm than you should do Refinement because of this:
Meshresults without Refinement:
Meshresults with a Refinement of Relative Element Size: 0,5 and Refinement Thickness: 0,5mm
Meshresults with a Refinement of Relative Element Size: 0,1 and Refinement Thickness: 0,1mm
I didn't see much of a difference between with and without doing Boundarylayers. Maybe someone else can explain that.
So the Results in Paraview look like that:
Maybe someone has an idea for a more precise model or extensions that they would like to contribute based on this example.
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- Posts: 113
- Joined: Mon Dec 03, 2018 3:47 pm
Re: Working Parameter Combinations
The cad Model.
- Attachments
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- Cartridge_v1.FCStd
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- Location: Germany
Re: Working Parameter Combinations
Here is my approach:
Mmmh, no clear shockfront visible. But residuals seems good. Or is it?
2D case with another bullet:
What about posting an excel-file with running examples?
But where can we put the files in one place?
Your 9mm bullet at Ma=0,99, solver Hisa, steady-state ("pseudo-transient"), 1/4 Modell.Mmmh, no clear shockfront visible. But residuals seems good. Or is it?
2D case with another bullet:
What about posting an excel-file with running examples?
But where can we put the files in one place?
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- Veteran
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- Joined: Sat May 20, 2017 12:06 pm
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Re: Working Parameter Combinations
and here with shockfront:
9 mm bullet shooting through pipe at Mach 1,75. mesh still too coarse...
9 mm bullet shooting through pipe at Mach 1,75. mesh still too coarse...
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Re: Working Parameter Combinations
Hello thschrader,
a formalized data sheet would be good for each case. And then an attached model... Hmmm...
a formalized data sheet would be good for each case. And then an attached model... Hmmm...
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- Posts: 113
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Re: Working Parameter Combinations
This is what it could look like:
If someone wants to change something on the wpc-datasheet, send me a message and I would unprotect the sheet.
If someone wants to change something on the wpc-datasheet, send me a message and I would unprotect the sheet.
- Attachments
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- CFDOF-Working Parameter Combinations_v0.1.xlsx
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