Conveyor belting belly pan?

[freebeard]

One approach is using expanded metal as a pan from body edge inwards to frame. Leave center open.

Expanded metal as in grating? I have this theory that semipermeable panels would guide the underbody air mass while allowing the pressure above the panel to equalize at lower velocity. Sort of a Fresnel effect for molecules. But I'd go with perforated rather than expanded.

[slowmover]

And/or add geotextile fabric.