FlexComp Inertia Calculation

[jbvilla]

Hi,

For my master’s thesis, I’m creating a bio-inspired flying squirrel model. I’m using the flexcomp element to simulate the patagium (skin between the limbs). I understand that flexcomp relies on the inertia model for the fluid dynamics, where each point in the flexcomp has its own inertia box.

My question is: How is the total inertia calculated for the entire flexcomp? Does every inertia box always contribute, or can some be blocked by others?

I ask because, in my simulation, the model reaches the ground in roughly the same time whether it falls horizontally or vertically. I would expect it to descend faster when oriented vertically. Or could it have to do with overlapping inertia boxes.

horizontal_fall_visualization.webm

vertical_fall_visualization.webm

vertical_fall_no_patagium_visualization.webm

[yuvaltassa]

I don't think anyone has tried the combination of flexcomp and fluid forces...

Looking at your last image, I see lots of transverse boxes that would not give you the aerodynamic profile you need for gliding.

I would probably start with a much simpler model with one or two geoms for wings.

Maybe what you want is possible, but you'd need to understand how the inertia is computed.

[jbvilla]

@yuvaltassa
I have read about how fluid forces are calculated, but I have not yet found an explanation for how this works with multiple inertia boxes. Can some be shielded so that they do not contribute resistance due to another inertia box, or does every inertia box always influence the calculations?

Furthermore, do you have any specific insights on fluid dynamics and flexcomps that could help clarify this?