2/1/11
Class 7 – Fluid Mechanics Uses and restrictions of Bernoulli’s equation Tuesday, February 1st
Stagnation, dynamic and hydrostatic pressure
A pitot-static tube is used to measure the velocity of helium in a pipe. The temperature are 40oF and 25 psia. A water manometer connected to the tube indicates a reading of 2.3 in. What is the helium velocity? Is it reasonable to consider the flow as incompressible?
Stagnation, dynamic and hydrostatic pressure
1 2/1/11
Use of the Bernoulli Equation: a) Free jets b) Confined flows c) Cavitation d) Flow measurement
2 2/1/11
Where is the lowest pressure going to occur in the hose?
a.
b.
c.
3 2/1/11
Water is siphoned from a tank. The water Water is siphoned from a tank. The water barometer indicates a reading of 30.2 ft. barometer indicates a reading of 30.2 ft. Determine the maximum value of h allowed Determine the maximum value of h allowed without cavitation occurring. Note that the without cavitation occurring. Note that the pressure of the vapor in the closed end of pressure of the vapor in the closed end of the barometer equals the vapor pressure. the barometer equals the vapor pressure.
Plan:
a) Use Bernoulli between 0 and 1 and 1 and 2 to find V2
b) Use continuity to find V3 c) Use Bernoulli between 1 and 3 to find h
Water is siphoned from a tank. The water barometer indicates a reading of 30.2 ft. Determine the maximum value of h allowed Which part of the Bernoulli expression without cavitation occurring. Note that the pressure of the vapor in the closed end of changes to take into account unsteady flow? the barometer equals the vapor pressure.
a) Use Bernoulli between 0 and 1 and 1 and 2 to find V2
b) Use continuity to find V3 c) Use Bernoulli between 1 and 3 to find h
A B C
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