prairie dogs live in underground burrows with at least 2 entrances. they ventilate their burrows by building a mound around one entrace, which is open to a stream of air. a second entrace at ground level is open to almost stagnant air. use bernoullis principle to explain how this construction creates air flow through the burrow
What happens when wind goes over the mound?
The answer is 102 km per hour.
To understand how the construction of prairie dog burrows creates air flow, let's first explain Bernoulli's principle. Bernoulli's principle states that as the speed of a fluid (such as air) increases, its pressure decreases. Conversely, when the speed of a fluid decreases, its pressure increases.
In the case of prairie dog burrows, the mound constructed around one entrance serves as an elevated point that catches the wind and directs it down into the burrow. Meanwhile, the second entrance at ground level is exposed to stagnant or slowly moving air.
Here's how the construction of the burrow utilizes Bernoulli's principle to create air flow:
1. Wind encounters the elevated mound around the first entrance. As the wind blows against the mound, it splits into two air streams: one moving over the mound and one moving around it.
2. The wind moving over the mound accelerates due to the narrowing space between the mound and the ground. According to Bernoulli's principle, as the wind speed increases, the pressure decreases.
3. Simultaneously, the wind moving around the mound experiences relatively stagnant air, which means its speed and pressure remain relatively constant.
4. Because the wind over the mound has lower pressure compared to the wind around the mound, a pressure difference is created.
5. As a result of this pressure difference, air is forced down into the burrow through the first entrance (which is open to the stream of air) and exits through the second entrance.
By using Bernoulli's principle, prairie dogs are able to create a pressure differential that effectively ventilates their burrows, bringing fresh air into the underground chambers and removing stagnant air. This helps them maintain a suitable environment within the burrow.