Tuesday, January 7, 2014

GATE, PSUs - Hydraulics, Irrigation, water resource Engg. notes - part 8


Hello there,
How have you been? Here is the 8th part of our notes for preparation of GATE and other examinations related to Civil Engineering.

  • Vorticity and stream function exist both in rotational and irrotational flow.
  • The flow of water in a wash hand basin when it is being emptied through a central opening, is an example of free vortex.
  • Mach number has its application in launching of rockets.
  • Thoma number has its application in cavitation phenomenon.
  • Reynolds number has its application in motion of submarine.
  • Weber number has its application in capillary flow in soil.
  • An error of 0.5% in the measurement of head in a V-notch causes an error of 1.25% in the discharge. 
  • Smaller eddy size and large intensity of turbulence would entail a greater energy dissipation in turbulent flow.
  • Shear velocity is a fictitious quantity.
  • A model of a weir made to a horizontal scale of 1/40 and vertical scale of 1/9 discharges 1 litre/sec. Then the discharge in the prototype is estimated as 1080 lps.
  • Laminar flow occurs between extensive stationary plates. The energy correction factor is nearly 2.0
  • In steady laminar flow of a liquid through a circular pipe of internal diameter D, carrying a constant discharge, the hydraulic gradient is inversely proportional to D^4.
  • For laminar flow between parallel plates separated by a distance 2h, head loss varies inversely as h^3.
  • A turbine works at 20 m head and 500 rpm speed. Its 1:2 scale model to be tested at a head of 20 m should have a rotational speed of nearly 1000 rpm.
  • In reciprocating pump, air vessel reduces the acceleration head and consequently  reduces the effect of friction head also.
  • The correct sequence, in the direction of flow of water for installations in a hydro-power plant is reservoir, pen-stock, surge tank and turbine.
All information is learned through books and practical exercises.

Thanks for visit!