Where Does the 0.6 Constant in Torricelli's Equation Come From?

[sting10]

Homework Statement

Hey, I am doing some work with torricellis equation and I have some questions. I am using the equation:

dH/dt*A(h)=-B*squareroot(2*g*h)

My question is, in my textbook it says the general formula is:

dH/dt*A(h)=-0.6*B*squareroot(2*g*h)

I want to know where the constant 0.6 comes from. Is it a constant which takes height for viscosity or turbulence and if so how do I find this constant?

Thanks.

 

[tiny-tim]

Welcome to PF!

Hi sting10! Welcome to PF!

(have a square-root: √ )

… I want to know where the constant 0.6 comes from. Is it a constant which takes height for viscosity or turbulence and if so how do I find this constant?

From http://en.wikipedia.org/wiki/Bernoulli's_principle#Real_world_application" …

The maximum possible drain rate for a tank with a hole or tap at the base can be calculated directly from Bernoulli's equation, and is found to be proportional to the square root of the height of the fluid in the tank. This is Torricelli's law, showing that Torricelli's law is compatible with Bernoulli's principle. Viscosity lowers this drain rate. This is reflected in the discharge coefficient which is a function of the Reynold's number and the shape of the orifice.[23: Mechanical Engineering Reference Manual Ninth Edition]