My aim is to calculate the drag coefficient (cd) for the G7 projectile at Mach 3. A drag table for this projectile can be found on this website: https://www.alternatewars.com/BBOW/Ball ... Tables.htm. Scroll a bit down.
1. Replicate the G7 with the image found on Wikipedia (https://en.wikipedia.org/wiki/Ballistic_coefficient)in the Part Design WB.
1 caliber = 10 mm
2. Add a box for the boundaries in the Part WB which surrounds the projectile. Use XOR to "fuze" the two bodies.
L = 250 mm; W = 100 mm; H = 100 mm
3. Add an analysis container in the CfdOf WB.
4. Create a mesh.
5. Add a mesh refinement.
6. Define the inlet.
Mach 3 = 1029 m/s
7. Define the outlet.
8. Define the walls.
9. Define the physics model.
10. Define the fluid - air, of course.
11. Initialise flow field.
In the end it looks like this:
12. Hit it!
My questions so far:
Is my boundary box sufficiently big enough?
Which mesh is best used for this application?
Are my settings correct to get an accurat result?
13. I used this tutorial (How to calculate aerodynamic forces with Paraview https://www.youtube.com/watch?v=J944HOj_4b0) to calculate the drag force.
14. With the force acting on the projectile it's trivial to calculate the cd (https://en.wikipedia.org/wiki/Drag_coefficient).
The problem is that this cd is wayyy too high. According to the table the cd at Mach 3 should be 0,2424.
The Freecad file with my work so far is attached.
Any constructive input would be much appreciated. Thanks!
