QUESTIONS Homework o Utube deflection 0 49 m
QUESTIONS
Homework o U-tube deflection: 0. 49 m o Gage pressure: 27. 7 k. Pa
SG = 0. 8
Manometer o Liquid flow deflection large; manometer fluid can be Hg, SG = 13. 6 o Gas flow deflection small; manometer fluid SG <~ 0. 9. Use inclined manometer
Example o Mott 3. 71 Figure 3. 36 Gage fluid has a SG = 0. 87 and L = 115 mm. = 15 o. Find PA.
Fluid statics o o • Liquid at rest: F = 0 Horizontal: equal in all directions Horizontal: dependent on depth Vertical: pressure prism P = h
Hydrostatic forces o o o • • • Pressure prism Distributed forces Force → vector Direction Magnitude Line of action: center of pressure
Fluid statics o F = hc. A magnitude o hcp = hc + (I/ hc. A) center of pressure
Submerged surface location o Top edge at liquid surface o Top edge submerged o Pressurized surface –equivalent depth of fluid o Inclined surface o Curved surface
Example o A heavy car veers off the road into a lake. It settles upright on the bottom. The front car door is 1. 2 m high and 1 m wide. The top of the door is 8 m below the lake surface. What is the force holding the door closed? Can the driver open the door? What can he do to survive?
Example o A rectangular gate is installed in a vertical wall of a reservoir. Find the magnitude of the resultant force and the center of pressure. What is the force of each latch?
Example o The square gate is eccentrically pivoted so that it automatically opens at a certain value of h. What is that value in terms of l ?
Homework o A gate for the spillway holds water at a normal high level mark. The spillway crest elevation is 2090. 0 ft. The gate span is 30 ft. What is the force on the two pins holding the gate in place?
Homework o The air above the liquid is at 40 psig. The SG of the liquid is 0. 8. The rectangular gate is 1. 0 m wide; y 1 = 1. 0 m; and y 2 = 3 m. What force P is needed to hold gate in place?
Homework o The inclined wall is 4 m wide. Find the magnitude of the resultant force and the center of pressure.
Centroid of compound area o Moment of compound area about any axis is equal to sum of the moments of its parts around the same axis o = (A 1 x 1 + A 2 x 2)/ AT
Assignment o Mott Chapters 3 & 4
References o. Images & examples • • • Fluid Mechanics Fundamentals & Applications, 6 th Edition, Cengel & Cimbala, Mc. Graw Hill Applied Fluid Mechanics, 6 th Edition, Mott, Prentice Hall Engineering Fluid Mechanics, 5 th Edition Crowe, & Roberson, Wiley q. Which of the examples were helpful? q. Why?
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