How to use Bernoulli's Equation Correctly?

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Bernoulli's equation can be applied to a system where a large pipe splits into two smaller pipes, but energy conservation is affected by losses such as friction. The main assumptions in deriving Bernoulli's equation include constant mass flow rate, frictionless conditions, and irrotational flow. Energy is not conserved in this context due to these losses, which occur during flow. The fluid type also influences the applicability of the assumptions, particularly regarding incompressibility for liquids versus gases. Understanding these principles is crucial for correctly applying Bernoulli's equation in fluid dynamics.
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One large pipe is splitted into 2 smaller pipes. Can we use Bernoulli's equation and say that the total head at a point in the large pipe is equal to a point at one of the 2 smaller pipes? Why is energy not conserved?
 
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There are 3 main assumptions in the derivation of the Bernoulli equation. What are they?
 
energy not conserved cuase of the losses-
as long as there is a flow then there is a difference in energy-which cuased the flow to occur-
there is the primary losses(friction)and the secondry(valve,bend-)which u don have here--
if u could show ur pipe system-it would be more clear for us-
wish i could help
 
Hi Fred,

Good hints. Check my answers and let me know if I got all of them! :smile:
FredGarvin said:
There are 3 main assumptions in the derivation of the Bernoulli equation. What are they?

1) Constant mass flow rate (no surges).
2) Frictionless (no heat transfer).
3) Irrotational (translational velocity only).

How'd I do?
Rainman
 
They are:
- Incompressible
- Inviscous
- Steady State
Since it also is applied along the streamline, so the irrotational part holds too.
A+ for Rainman

As for the main post, energy will not be conserved because of the losses due to friction. Also, you do not state the fluid involved. If it is a liquid, then the incompressibility assumption is pretty much valid. If it is a gas, you need to be concerned with it.
 

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