Derivation of discharge over rectangular weir

[Ravikant Rajan]

How does the velocity at an elemental height h equates to √(2gh)? My application of Bernoulli's equation is not yielding the result. Please show the process.

Thank you

 

[BvU]

So what is the difference between your handling of Bernoulli and, e.g., this one ?

 

[Ravikant Rajan]

So what is the difference between your handling of Bernoulli and, e.g., this one ?

Thank You so much.
The exiting fluid also experiences same atmospheric pressure as the top point.