GATE, PSUs - Hydraulics, Irrigation, water resource Engg. notes - part 4

Hello there,
How have you been? Here is the 4th part of our notes for preparation of GATE and other examinations related to Civil Engineering.

• Apart from inertia force, Viscous force is most important force for the motion of submarines under water.
• In case of capillary waves in channels viscous force is unimportant.
• In case of a flow through a long capillary tube, inertia force would be unimportant.
• For the resistance to motion of a ship's model through water, the basic similitude criteria is Reynold's Law and Froude's Law
• The causes of cavitation are high suction lift and high pump speed.
• An impulse turbine operates by initial complete conversion to kinetic energy.
• Water turbines may be put in the decreasing order of specific speeds as Propeller turbine, Reaction turbine, Impulse turbine.
• Two geometrically similar units are homologous if they have similar streamlines.
• Impulse turbine is ideal for high head development.
• A reciprocating pump does not need priming.
• A centrifugal pump can run at high speed.
• Pumps in increasing order of specif speed : Centrifugal pumps, mixed flow pump, axial flow pumps.
• The specific speed of a turbine is defined as the speed of a unit  of such a size that it produces unit power for unit head.An isentropic process is always frictionless and adiabatic.
• Momentum and continuity equations are used to produce Rayleigh lines.
• For isentropic flow of air: Critical pressure ratio = 0.528; Critical Temperature Ratio = 0.833; Critical Density Ratio = 0.634

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