Stack Effect in a soft fabric pipe seems questionable because the stack effect is based on the difference of the pressures inside and outside the pipe and the soft fabric pipe is supposed to deflate and become flat if pressure outside is greater then inside.

If it is really so then it could be meaningful to create the vortex inside the pipe to keep the low pressure close to the axis and the ambient pressure near the walls.

As a result I created the experiment description here:

Deleted research item The research item mentioned here has been deleted

Is anything ( or everything ) fundamentally wrong with it ?