Pressure and velocity of fluid

[MechaMZ]

Homework Statement

Let's say the surface of the fluid is very big as compare to the tube diameter.
Are my assumptions below correct?

V_A=0

V_B(inlet of the tube) = V_E, i think so because the diameter of the tube is constant.
And the velocity through the tube all are constant.

or V_B(inlet of the tube) = 0? but it could be right?

Which point has the lowest pressure? should be P_C or P_E?

Are the pressure of P_B and P_E the same?

Is the P_D = 0?

will all the pressure be different value if the fluid in a stationary motion?

thanks all.

 

[MechaMZ]

anyone can help in this question??

 

[kerimek]

I would first like to clarify that the statement is not clear enough to provide a definitive answer. It is important to specify the type of fluid and the specific conditions of the system in order to accurately determine the pressure and velocity. However, based on the assumptions provided, here are some responses:

- If the surface of the fluid is significantly larger than the tube diameter, it can be assumed that the fluid is in a state of laminar flow, where the velocity is constant throughout the tube. This is known as the "fully developed flow" assumption.

- Based on this assumption, it is correct to say that VA=0 and VB(inlet of the tube) = VE. This is because the velocity at point A, which is at the surface of the fluid, is zero due to the no-slip condition between the fluid and the surface. And since the diameter of the tube is constant, the velocity at the inlet (VB) and outlet (VE) of the tube will also be constant.

- It is not clear what the point PC refers to in this system, so I cannot determine the pressure at that point. However, if the fluid is in a state of laminar flow, the pressure will decrease along the direction of flow, with the lowest pressure at the outlet (PE).

- The pressures at PB and PE will not necessarily be the same, as the pressure at PE will be lower due to the Bernoulli's principle, which states that the pressure decreases as the velocity increases.

- PD can only be determined if the pressure at point D is specified. It is not necessarily zero, as it could be affected by factors such as the height of the fluid column above point D.

- In a stationary motion, the pressure at each point will remain constant, but the velocity may vary depending on the conditions of the system. It is not possible to determine the exact values without more information.

I hope this helps, but please note that these are general responses and may not apply to all cases. More information is needed to provide a specific and accurate answer.