https://asknature.org/strategy/asymmetric-burrow-openings-create-passive-ventilation/
Differences in position and shape of burrow openings of black-tailed prairie dogs create passive ventilation from wind energy by altering air pressure
Prairie dogs are highly social rodents that build extensive underground burrows in the plains of North America to house their family groups. The burrows can reach 10 m (32 ft) in length, and this size means that diffusion alone is not sufficient to replace used air inside the burrow with fresh air. The way that a prairie dog builds the openings to its burrow, however, helps to harness wind energy from the windy plains and create passive ventilation through the burrow’s tunnels.
As air flows across a surface, a gradient in flow speed forms, where air moves more slowly the closer it is to the surface. The prairie dog is able to take advantage of this gradient by building a mound with an elevated opening upwind and a mound with a lower opening downwind. Wind velocity then is faster over the higher opening than the lower opening. Since an increase in speed creates a decrease in pressure (according to what is called “Bernoulli’s principle”), the burrow now has openings with two different air pressures on them. The result of this difference is one-way air flow through the burrow as air rushes out the higher opening and is drawn in to the lower opening.
It mentions that the openings have to be specifically upwind or downwind. Unless im mistaken, that doesnt matter at all. You could swap the height of each entrace and it would reverse the airflow. The only way that would matter afaik is if the shape or size of the entrace/tunnel changes. If your tunnel has backflow circuits, it will increase the pressure at the meet and therefore decrease flowthrough, effectively increasing standing pressure “upwind” through the tunnel, which is how a tesla valve functions. Or if the area of the cross section of the entrance or tunnel decreases, that will constrict flow. But the higher entrance being upwind or downwind shouldnt matter at all, unless im missing something?
Been on the internet too long, expected to see Saddam in this picture.
I subscribed for the pictures of tan eggs, but the science is a great bonus!
Conclusion: Bernoulli was a prairie dog
I want my internet full of interesting tidbits like this. Thank you!
who taught those belegged kiwi fruits physics??
I thought it was just air pressure drops the higher up you are.
Well it turns out that’s not all there is to air
It just works😆
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