A Pitot-static tube, with a coefficient of velocity 0.98 is used to measure the velocity of water in a pipe. The stagnation pressure recorded is 3 m and the static pressure is 0.5 m. What is the velocity of flow?
The integral momentum equation requires the following assumption in the flow
A flow through an expanding tube at a constant rate is called
Flow of liquid through a long pipe of constant diameter at a constant rate is steady uniform flow; flow of liquid through a long pipe line of constant diameter, at either increasing or decreasing rate is unsteady-uniform flow; flow of liquid through a tapering pipe at a constant rate is steady-nonuniform flow and flow through a tapering pipe at either increasing or decreasing rate is unsteady- non-uniform flow.
To avoid the tendency of separation of flow at the throat in a Venturimeter, the ratio of the diameter at the throat to the diameter of the pipe should be
The ratio of throat to inlet diameters d2/d1 may range between 0.75 and 0.25, but the most commonly used ratio is 0.50.
A smaller ratio gives a higher difference in the piezometric heads (between the inlet and the throat) which can be measured more accuratedly by a differential manometer. At the same time, a smaller throat (that is a lower d2/d1 ratio) will mean higher throat velocities which may cause pressures low enough to liberate dissolved gases thereby creating conditions for cavitation to set in.
Venturimeter is used to measure
A venturi meter is a device which is used for measuring the rate of flow of fluid through a pipe. The basic principle on which a venturi meter works in that by reducing the cross-sectional area of the flow passage, a pressure difference is created and the measurement of the pressure difference enables the determination of the discharge through the pipe.
A pipe of length more than double the diameter of the orifice fitted internally or externally to the orifice is called
A point in a compressible flow where the velocity of fluid is zero, is called
At vena-contracta velocity of fluid is maximum at stagnation point velocity is zero and all kinetic energy is converted to pressure energy.
The equation P/w + V2/2g + Z = constant is based on the following assumptions regarding the flow of fluid:
The equation is Bernoulli’s equation. It is based on following assumptions:
(i) flow is steady
(ii) fluid is incompressible
(iii) fluid is. non-viscous since viscous force has been neglected; and
(iv) it is applicable to points along a streamline
A fluid jet discharging from a 4 cm diameter orifice has a diameter 3 cm at its vena contracta. If the coefficient of velocity is 0.98, the coefficient of discharge for the orifice will be
For an orifice the coefficient of discharge Cd, coefficient of velocity Cv and coefficient of contraction Cc is related as,
Cd = Cc x Cv
Cd = (0.75)2 x 0.98
The coefficient of velocity for an orifice is given by (using usual notation)