Rectangular Orifice
Discharge through a rectangular orifice
Contents
Key Facts
Gyroscopic Couple: The rate of change of angular momentum () = (In the limit).- = Moment of Inertia.
- = Angular velocity
- = Angular velocity of precession.
Blaise Pascal (1623-1662) was a French mathematician, physicist, inventor, writer and Catholic philosopher.
Leonhard Euler (1707-1783) was a pioneering Swiss mathematician and physicist.
Discharge Through A Small Rectangular Orifice
An orifice is considered to be small, if the head of water above the orifice if over 5 times the height of the orifice. In a small rectangular orifice, the velocity of water in the entire cross-section of the jet is approximately constant, so the discharge can be approximately with the relation, or where,- = Coefficient of discharge for the orifice
- a = Cross sectional area of the orifice
- h = Height of the liquid above the center of the orifice
- b = Width of the orifice
- d = Depth of the orifice
Discharge Through A Large Rectangular Orifice
With a large rectangular orifice, the velocity of the liquid particles is not constant, because there is a considerable variation of effective pressure head over the height of an orifice: Velocity of liquid varies with the available pressure head of the liquid.MISSING IMAGE!
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- = Height of liquid above the top of the orifice
- = Height of liquid above the bottom of the orifice
- = Breadth of the orifice
- = Coefficient of discharge
Example:
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Example - Discharge through a large rectangular orifice
Problem
A large rectangular orifice of 1.5m wide and 0.5m deep is discharging water from a tank. If the water level in the tank is 3m above the top edge of the orifice, find the discharge through the orifice. Take coefficient of discharge for the orifice as 0.6.
Workings
Given,
- b = 1.5m
- d = 0.5m
- = 3m
- = 0.6
Solution
Discharge through the orifice, Q = 3.59 m3 /s