What Is the Impact of Throat Velocity on Pressure According to Bernoulli's Law?

  • Thread starter Thread starter gerdsmit
  • Start date Start date
  • Tags Tags
    Law
AI Thread Summary
Bernoulli's law indicates a direct relationship between pressure drop and fluid velocity at the throat, leading to questions about the implications of achieving a high negative absolute pressure through increased throat velocity. The equation suggests that if P2 is negative, it implies an increase in the original pressure P1. However, the concept of negative absolute pressure is nonsensical, as absolute pressures cannot be negative. Additionally, the maximum velocity achievable in any throat is limited to sonic velocity. This discussion highlights the theoretical boundaries and practical limitations of fluid dynamics.
gerdsmit
Messages
4
Reaction score
0
According to Bernouilli's law there is a direct relation between pressure drop and fluid's velocity at the throat. What would be the physical meaning of a high value negative absolute pressure that theoretically can be achieved by increasing fluid's throat velocity.
 
Physics news on Phys.org
It would probably mean that the pressure experienced before the throat is increased,

In the eq P1 + 1/2DV1^2 = -P2 + 1/2DV2^2,
bring _p2 to the other side

=>P1+P2 + 1/2DV1^2 = 1/2DV2^2

(D=density,P1 = initial press.,P2=final pressure,same for V1 and V2)

implying that the original pressure is increased...
Hope you understand what I am trying to say...(good question though)
 
gerdsmit said:
According to Bernouilli's [equation] there is a direct relation between pressure drop and fluid's velocity at the throat. What would be the physical meaning of a high value negative absolute pressure that theoretically can be achieved by increasing fluid's throat velocity.

It is nonsensical since absolute pressures cannot be negative.

CS
 
Absolute limit of velocity in any throat is going to be sonic velocity. There's your limit right there.
 
Hello! Let's say I have a cavity resonant at 10 GHz with a Q factor of 1000. Given the Lorentzian shape of the cavity, I can also drive the cavity at, say 100 MHz. Of course the response will be very very weak, but non-zero given that the Loretzian shape never really reaches zero. I am trying to understand how are the magnetic and electric field distributions of the field at 100 MHz relative to the ones at 10 GHz? In particular, if inside the cavity I have some structure, such as 2 plates...

Similar threads

Back
Top