OpenFOAM – THIRD ATTEMPT. AIR FLOW THROUGH A SUGAR BEET CLAMP w COVER
Just a quick reminder
- 1st attempt: flow over a structure the shape of a clamp
- 2nd attempt: flow through a porous clamp
- This attempt: flow through a porous clamp with a less porous cover added
The cover is 5cm normal to the surface. At a ca. 34 degree angle of repose, this makes the cover about 9.75cm wide along the x axis on the sides of the clamp. I’ve added the cover by drawing it in the geometry in Blender. It was pretty straight forward trig to get the thicknesses and drawing anchor points. Once exported from Blender, all the control files for OpenFOAM meshing and solution were updated accordingly (generally just copy and paste-ing the sections for “clamp” and renaming them).
The clamp is an idealised smooth, symmetrical shape, of 9 meters width at the base and 2.7 meters high. The air flow is left to right, at 5m/s. And, again, I’ve just built a model to test the set-up – some key parameters are not an accurate reflection of what is the likely reality.
In comparison to the 2nd attempt, with no cover, the addition of a less permeable cover makes sense to me:
The clamp had a Darcy coefficient of 50, while the cover is 200. Both very low numbers.
Looking at the entire clamp with the 0-5m/s colour scale and comparing to the 2nd attempt, it’s much more green and much less rainbow:
One thing that strikes me from this whole-of-clamp image is that having the cover not go all the way to the ground might not matter as much as I’ve assumed, given the low velocities down there. We’ll see.