FLOW THROUGH AN ORIFICE
Consider a tank fitted with a small circular orifice and fluid is discharging free in to the atmosphere.
Let's consider two sections 1 and 2
Section 1 is top of the upstream side of the orifice and section 2 being slightly to the right of orifice on the datum line and at the vena contracta .
Applying Bernaulli's equation at the point 1 and 2.
ie, p1/eg+v1^2/2g+z1=p2/eg+v2^2/2g+z2
But p1=pa
Where, pa is the atmospheric pressure.because the point 1 and 2 are contact with outside pressure.so these pressures are considered as pa.
=v1^2/2g+z1=v2^2/2g+z2
The cross sectional area of the tank is very large.the liquid at the point 1 is practically at rest when compared ton the point 2 at vena contracta.
v1=0
There for z1=v2^2/2g+z2
Assuming the datum line along the centre of the orifice.then,
z1=H
z2=0
H=v2^2/2g+0
ie,H=v2^2/2g
v2^2=2gH
v2=2gH
This is the theoretical velocity.
Consider a tank fitted with a small circular orifice and fluid is discharging free in to the atmosphere.
Let's consider two sections 1 and 2
Section 1 is top of the upstream side of the orifice and section 2 being slightly to the right of orifice on the datum line and at the vena contracta .
Applying Bernaulli's equation at the point 1 and 2.
ie, p1/eg+v1^2/2g+z1=p2/eg+v2^2/2g+z2
But p1=pa
Where, pa is the atmospheric pressure.because the point 1 and 2 are contact with outside pressure.so these pressures are considered as pa.
=v1^2/2g+z1=v2^2/2g+z2
The cross sectional area of the tank is very large.the liquid at the point 1 is practically at rest when compared ton the point 2 at vena contracta.
v1=0
There for z1=v2^2/2g+z2
Assuming the datum line along the centre of the orifice.then,
z1=H
z2=0
H=v2^2/2g+0
ie,H=v2^2/2g
v2^2=2gH
v2=2gH
This is the theoretical velocity.
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