I Explain Bernoulli at the molecular level?

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AI Thread Summary
Static pressure remains equal to atmospheric pressure regardless of vehicle speed, as demonstrated by static ports in pitot tubes. The discussion highlights that Bernoulli's principle does not apply in this context, as static pressure does not decrease with increased airflow speed. Instead, the focus shifts to understanding how static pressure is transmitted at the molecular level and the role of pressure gradients in accelerated flow. The conversation also emphasizes that pressure is frame invariant, while speed is frame dependent, complicating the relationship between the two. Overall, the dialogue seeks to clarify the conditions under which Bernoulli's principle is valid and the physical implications of static pressure in various scenarios.
  • #251
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Lets assume that the flow in the control volume is uniformly distributed, and experiences a constant acceleration along the circular arc ##s##.

In other words ##\ddot s = k## implies:

$$ \frac{d \dot s }{d \theta} \frac{d \theta }{dt} = k $$

Since ## \dot s = r \dot \theta ##:

$$ \frac{d \dot s }{d \theta} \frac{\dot s }{r} = k $$

Separate variables, integrate this over ##\theta##, with ## \dot s = V## implies that the scalar velocity of the flow along at any point along the arc is given by:

$$ V = \sqrt{2kr \theta + V_1^2} $$

Does anyone have complaints about the "lever pulling" I'm about to do for fear of basic representation of the unsteady terms in the Mass Continuity/ Energy equations before I go further?

I believe I can get the pressure ##P_2## at the outlet as function of ## V_1, \dot V_1, k ## etc... (the velocity of the cart, cart acceleration, etc... ). Explicitly I'm not sure, but at least implicitly it looks like I have it.
 
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  • #252
rcgldr said:
I agree. I'm waiting to see if someone wants to move all the glider related posts to another thread. If they just want to delete them, I wouldn't have an issue with that either, but don't know about the others involved. I did go through and did strike-through on my prior posts.
Paging @berkeman and @russ_watters.
 
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