Review & Preview Questions, Fall 2010 Semester
REVIEW:
1. How are minor loss coefficients determined?
2. How are minor losses expressed?
3. Why is the exit loss coefficient equal to 1.000 for a liquid leaving a pipe and entering a very large
tank?
PREVIEW:
1. For convenience in categorizing the kinds of pipe problems you'll solve in your career, the author has
come up with 3 categories of pipe flow problems. What are they?
2. For Type II problems, what is the suggested procedure for solving the problem? How do you guess an
f value?
3. For Type III problems, what is a typical value of f to use as a first guess?
REVIEW:
1. What two parameters impact pressure loss in turbulent flow but not laminar flow?
2. T/F. Friction loss in smooth pipe is equal to zero because the pipe is smooth (epsilon =0).
3. Fill in the blanks: The friction factor, f, is a function of (blank) for laminar flow, a function of (blank) for
turbulent flow, and a function of (blank) for wholly turbulent flow.
PREVIEW:
1. List 6 different kinds of "appurtenances" on pipes that produce minor losses.
2. How are minor losses expressed? What are they a function of?
REVIEW:
1. What Reynolds number qualifies for laminar flow? Turbulent?
2. What drives fluid flow in a full horizontal pipe?
3. List 4 differences between laminar and turbulent flow.
PREVIEW:
1. We won't talk about 8.3.1 and 8.3.2.
2. What are the two kinds of losses considered in pipe flow?
3. What two additional parameters are considered in turbulent flow?
4. Write the Darcy-Weisbach equation.
REVIEW:
1. How can you tell if you should use Froude or Reynolds number modeling when working with models?
2. What does the greek letter lambda with various subscripts stand for?
3. What does it mean to 'creatively multiply by 1," and why do you need to do it when considering
scales?
PREVIEW:
1. For what range of Reynold's numbers is pipe flow laminar? Turbulent?
2. What kind of mathematical equation describes the velocity distribution of laminar flow in a pipe?
3. If you have laminar flow in an inclined pipe, what does the angle theta refer to?
REVIEW:
1. What are some examples of external surface forces found in the momentum equation (i.e. Fx and Fy)
2. In the momentum equation, why do we like to assume steady, incompressible flow with velocity
normal to the control surface?
3. What is the main difference between the Bernoulli and Energy Equations?
PREVIEW:
1. Please print out the handout for class on Wednesday from the website.
2. Note: Power is equal to gamma x Q x h, where gamma is the unit weight of the fluid, Q is the
discharge, and h is the head. Head could refer to the water depth above a turbine, or the pressure head
added by a pump, or even the energy loss in a system expressed in ft or m.
REVIEW:
1. How do you incorporate the pressure onto the free body diagram for practice problem 1?
2. For practice problem 3, why is there a pressure force at control surface 1 but not at control surface 2?
3. For practice problem 2, why is it easier to take a control volume right around the plate rather than
include the water column between the jet exit and the plate?
PREVIEW:
1. Only look at equation equation 5.57 for Monday.
2. How is the energy equation different than the Bernoulli equation?
3. Using my convention of labeling points of analysis "1" for upstream and "2" for downstream, re-write
equation 5.57 (what is "out" and "in?")
4. Note: Power is equal to gamma x Q x h, where gamma is the unit weight of the fluid, Q is the
discharge, and h is the head. Head could refer to the water depth above a turbine, or the pressure head
added by a pump, or even the energy loss in a system expressed in ft or m.
REVIEW:
1. How can you tell if a conservation of mass problem is steady or unsteady?
2. Why does the left hand side of the momentum equation simplify to the sum of forces?
3. What are the 5 suggested steps for solving a momentum problem?
4. Why do we need a free body diagram for momentum problems while we did not for conservation of
mass problems?
PREVIEW:
1. Print out the handout from the website that pertains to the lecture on October 15. We'll work on
those problems in class.
REVIEW:
1. How can you deterimine if a conservation of mass problem is steady or unsteady?
2. Write on the board the conservation of mass equation assuming unsteady flow, compressible fluid,
velocity perpindicular to all control surfaces.
PREVIEW:
1. Why can the left hand side of the momentum equation be written as the sum of forces?
2. Why can't we "drop" the density term from the momentum equation even if we're dealing with
incompressible and constant density fluids?
3. What is the simplest form of the momentum equation?
REVIEW:
1. Why is the left hand side of the conservation of mass equation equal to zero?
2. Write on the board the conservation of mass equation assuming that flow is steady and
incompressible, but that there are 4 control surfaces, and the density of the fluid is different at each
control surface. All velocities at control surfaces are uniform and perpindicular to the control surfaces.
PREVIEW:
Print out the examples from the link on the class web page for Monday!!
REVIEW:
1. If the HGL is beneath a pipeline, what do you know abou the pressure in the pipeline?
PREVIEW:
1. State the Reynolds transport theorem in your own words.
2. Give an example of a control volume and control surfaces.
REVIEW:
1. State one of the restriction on the use of the Bernoulli equation.
2. State another.
3. State another.
4. State another.
PREVIEW:
1. Explain the differences between the Eulerian and Lagrangian points of view using a real world
example.
2. Describe a one dimensional flow. Two-D. Three-D.
3. We won't cover 4.1.4
4. What are the two separate effects of acceleration?
REVIEW:
1. In general, what is a strategy for assigning points to solve the Bernoulli equation?
2. Where in a siphon pipe is the pressure the most negative?
3. What is the limit on the height water can be siphoned?
PREVIEW:
1. Define the hydraulic grade line.
2. Define the energy grade line.
3. T/F. The elevation of the hydraulic grade line is equal to the elevation of the energy grade line for a
lake, ocean, or tank of water with no inflow and no outflow.
REVIEW:
1. Write the Bernoulli equation across a streamline
2. What are the 5 steps I suggest you follow for solving a problem involving the Bernoulli equation?
3. What is the velocity equal to at a location where you have stagnation pressure?
PREVIEW:
1. Look at Figure 3.7. Using the Bernoulli equation ACROSS a streamline, show that the pressure at point
outside the tank is equal to zero.
2. Write the continuity equation.
3. Where in a siphon pipe is the pressure the most negative?
REVIEW:
1. Why do you use the distance from the fluid interface to the CENTROID of a submerged plane surface
to calculate the total FORCE acting on that plane?
2. Why is the center of pressure a bit lower?
3. What is buoyant force equal to?
PREVIEW:
1. Print out the handout for this lecture from the web site and bring to class.
2. What coordinate system are we using to derive the Bernoulli equation along a streamline?
3. In the intermediate form of the Bernoulli equation (the one with the angle theta in it), how is theta
referenced?
4. The sum of what three terms are constant along a streamline?
REVIEW:
1. What is the horizontal force on a curved submerged surface equal to?
2. What is the vertical force on a curved submerged surface equal to?
3. How does problem 2.49 represent a 'virtual fluid'? How does that help you find the vertical force
acting on the curved portion of the tank wall?
PREVIEW:
1. Define buoyancy.
2. Define buoyancy.
3. Define buoyancy
REVIEW:
1. How do you solve any manometer problem?
2. 1470 psi is equal to how many feet of pressure head in water?
3. Why does the resultant force on a submerged plane surface act below the centroid of the plane?
PREVIEW:
1. What is the vertical component of force on a submerged curved surface equal to?
2. What is the horizontal component of force on a submerged curved surface equal to?
3. How do you find the TOTAL force acting on a submerged curved surface?
REVIEW:
1. Why has traditionally mercury been a good choice for measuring atmospheric pressure?
2. Express atmoshperic pressure (14.7 psi) in feet of glycerin (see inside cover for properties).
PREVIEW:
1. What limitations of a simple manometer (called a piezometer) are overcome with a u-tube
manometer?
2. Look at Figure 2.12. Explain the orientation of the axes and what it is we're looking at.
3. Define the center of pressure. Why is it a bit below a submerged plane's centroid?
REVIEW:
1. Why has traditionally mercury been a good choice for measuring atmospheric pressure?
2. Express atmoshperic pressure (14.7 psi) in feet of glycerin (see inside cover for properties).
PREVIEW:
1. What limitations of a simple manometer (called a piezometer) are overcome with a u-tube
manometer?
2. Look at Figure 2.12. Explain the orientation of the axes and what it is we're looking at.
3. Define the center of pressure. Why is it a bit below a submerged plane's centroid?
REVIEW:
1. The height of capillary rise due to surface tension is a function of what (in addition to, obviously,
surface tension)?
2. Define pressure head.
3. What is the pressure head of 120 mm of mercury in feet of water?
PREVIEW:
1. What is a manometer, and what limitations does it have?
2. What is a U-tube manometer, and how does it overcome the limitations of a simple manometer?
3. Express sub-atmoshpheric pressure using 3 different adjectives.
REVIEW:
1. Define saturation vapor pressure.
2. Define cavitation.
3. Give an example of damage induced by cavitation.
PREVIEW:
1. Define surface tension.
2. When calculating the height of capillary rise, what is the length over which surface tension acts?
3. State Pascal's Law.
4. What is the interpretation of "pressure head?"
Old HM Assignments
Wednesday, Oct 20
HW SET 19: 5.24, 5.26, 5.27 (< 3 x 10^-4 m^3/s)
Monday, 18 Oct
HW SET 18: 5.15 (< 10 lb); 5.16; 5.18
Friday, Oct 15
HW SET 17: 5.9 (< 10 ft/s); 5.12
Wednesday, Oct 13
HW SET 16: 5.6, 5.7 ((a) 5900 lb/hr; (b) 244,000 lb/hr); 5.8
Monday, Oct 11
HW SET 15: 5.4
Friday, Oct 8
HW SET 14: 4.10, 4.15 (ans (a) < -50 m/s^2; (b) > 6g) 4.17 (ans (a) < -25 deg C/s; (b) < -25 deg
C/s
Wednesday, Oct 6
HW SET 13: 3.57
Friday, Oct 1 or Monday, Oct 4
HW SET 12: 3.28, 3.30, 3.38
Wed, Sep 29
HW SET 11: 3.10, 3.17, 3.22
Monday, Sep 27
HW SET 10: 3.4, 3.5 ((a) is < 0 psi; (b) is > 0 psi
Friday, Sep 24:
HW SET 9: 2.51 (< 500 lb); 2.52, 2.57 (< 2500 kg)
Wednesday, Sep 22
HW SET 8: 2.48, 2.49 (ans. around 5,000 lb in each direction; this is simply a guide to help you
so you know if you're on the right track); 2.50
Monday, Sep 20
HW SET 7: 2.27 (answer: > 9000 lb); 2.29 (ans: > 20,000 lb and > 10 ft); 2.32
Friday, Sep 17
HW SET 6: 2.12, 2.16, 2.21
Wednesday, Sep 15
HW SET 5: 2.4, 2.5, Handout
Monday, Sep 13
HW SET 4: 1.38, 1.45, 1.47
Wednesday, Sep 8
HW SET 3: 1.25, 1.28
HW SET 2: 1.11, 1.16, 1.22
Friday, Sep 3
HW SET 1: 1.2, 1.3, 1.6