Force Exerted by fluid on a Bend, an Enlargement, or a Contraction

In summary, the conversation is about an attempt to convert a book equation to a FE manual equation. The equation being discussed is Fx = QpV1 + P1A1 - QpV2Cosa - P2A2Cosa. The conversation also mentions a sign error in eq 11.49 in the second attachment and a frustration with trying to solve a problem using the FE manual's equation.
  • #1
sandmanvgc
26
1
Homework Statement
I’m looking at the FE manuals equation which to me doesn’t look the same as one in practice problem review book. Am I wrong and not looking at it right?
Relevant Equations
3rd pic attempt to convert book equation into manual
My attempt to try and convert book equation to FE manual equation in 3rd pic
Rich (BB code):
Fx = QpV1 + P1A1 -  QpV2Cosa - P2A2Cosa

Fx = P1A1 - P2A2Cosa+ Qp(V2Cosa +V1)

P1A1 - P2A2Cos(a) - Fx = -Qp(V2Cosa +V1)
 

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Last edited:
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  • #2
There's a sign error in eq 11.49 in the second attachment. It should clearly be ##(-\dot m\bar V_2-...##, not ##(\dot m\bar V_2-...##.
 
  • #3
haruspex said:
There's a sign error in eq 11.49 in the second attachment. It should clearly be ##(-\dot m\bar V_2-...##, not ##(\dot m\bar V_2-...##.
The book has an example problem too, I wasn't getting the answer using the FE manual's equation. Frustrating time lost on trying to do these
 

1. What is the force exerted by fluid on a bend?

The force exerted by fluid on a bend is known as the centrifugal force. This force is caused by the change in direction of the fluid as it flows around the bend, and it is directed away from the center of curvature of the bend.

2. How is the force exerted by fluid on an enlargement calculated?

The force exerted by fluid on an enlargement can be calculated using the Bernoulli's equation. This equation takes into account the change in velocity and pressure of the fluid as it passes through the enlargement, and can be used to determine the force exerted on the walls of the enlargement.

3. What is the significance of the force exerted by fluid on a contraction?

The force exerted by fluid on a contraction is important in determining the efficiency of a fluid system. This force can cause a decrease in the fluid's velocity as it passes through the contraction, resulting in a loss of energy. Therefore, minimizing this force is crucial in designing efficient fluid systems.

4. How does the density of the fluid affect the force exerted on a bend or enlargement?

The density of the fluid plays a significant role in determining the force exerted on a bend or enlargement. A denser fluid will have a greater inertia and will exert a larger force on the walls of the bend or enlargement. This is why it is important to consider the density of the fluid when designing fluid systems.

5. Can the force exerted by fluid on a bend or enlargement be reduced?

Yes, the force exerted by fluid on a bend or enlargement can be reduced by using different techniques such as streamlining the shape of the bend or enlargement, increasing the radius of the bend, or using a diffuser to gradually increase the cross-sectional area of the flow. These techniques can help minimize the force exerted by the fluid and improve the efficiency of the system.

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