MEEN 345 EXAM 2 QUESTIONS AND VERIFIED
ANSWERS
Lab 6
Which of the following is not the objectives of Lab 6?
a) determine discharge coefficient of flow through an orifice
b) determine the contraction coefficient of the flow through an orifice
c) determine the velocity coefficient of the flow through an orifice
d) verify the relation between the head and the flow rate through an orifice
e) determine the head loss through piping systems - Answers - e) determine the head
loss through piping systems
Lab 6
Choose the location of the vena contracta from the flow through an orifice
a) inside the tank
b) directly outside orifice
c) past orifice where flow radius increases - Answers - b) directly outside orifice
Lab 6
What is the use of the pointer in lab 6? - Answers - To measure the diameter of the jet
Lab 6
What is the use of the pitot tube in lab 6? - Answers - To measure the stagnation
pressure of the jet
Lab 6
You predicted the flow rate through an orifice using continuity and bernoullis equation.
The actual flow rate was less than the predicted flow rate. What was the most probable
cause? - Answers - The predicted result disregarded all frictional effects
Lab 6
The volumetric flow rate, Q through an orifice is measured with the decreasing water
level, H in the tank. What is the relationship between the volumetric flow rate and the
pressure head in the tank?
a) Q∝H
b) Q∝H^2
c) Q∝√H
d) Q∝ log H - Answers - c) Q∝√H
Lab 6
A fluid passes through a sharp-edged orifice in the base of the tank. Two manometers
are installed: the manometer A connects to a Pitot tube which is positioned at the vena
, contracta of the fluid stream, the other manometer B connects to a pressure tapping in
the base of the tank. (a) Compare the heights of three water levels: manometer column
A and B, and water tank, C. - Answers - A<B=C
Lab 6
What is the reason of different heads in manometers?
a) Frictional head loss through an orifice
b) Acceleration of water due to gravity
c) elevation head difference
d) velocity head difference - Answers - Frictional head loss through an orifice
Lab 7
Which of the following is not an objective of Lab 7?
Measure the mean pressure distribution around the circumference of a circular cylinder
for three fluid speeds
Use a multi-tube manometer system to measure the pressures distribution
Measure the drag force exerted on the cylinder by means of a force dynamometer
Calculate the net force on the cylinder due to the pressure distribution
Nondimensionalize the data to see how scaling works - Answers - Measure the drag
force exerted on the cylinder by means of a force dynamometer
Lab 7
The coefficient of pressure is a non-dimensional number to scale pressure
measurements from a model to a full sized item. Which of the following is an advantage
of a non-dimensional number? Select all that apply.
It expresses the functional relationship between the variables in dimensionless terms.
It reduces the number of variables involved in a physical phenomenon.
The design curves can be developed from experimental data or direct solution of the
problem.
It allows to compare different systems by simplifying the problems in dimensionless
forms. - Answers - all answers are correct
Lab 7
The following plot shows the pressure distribution on a cylinder that is placed in a flow.
What is the main reason why the experimental data are different from the theoretical
calculation? (Pre Lab 7, Q4)
Theoretical results did not account for flow separation and viscous friction near the
body's surface.
The cylinder rotated fast about its axis.
The experiment was conducted at extremely low Reynolds number.
The discrepancy was introduced by assuming a uniform velocity profile approached the
cylinder. - Answers - Theoretical results did not account for flow separation and viscous
friction near the body's surface.
Lab 7
ANSWERS
Lab 6
Which of the following is not the objectives of Lab 6?
a) determine discharge coefficient of flow through an orifice
b) determine the contraction coefficient of the flow through an orifice
c) determine the velocity coefficient of the flow through an orifice
d) verify the relation between the head and the flow rate through an orifice
e) determine the head loss through piping systems - Answers - e) determine the head
loss through piping systems
Lab 6
Choose the location of the vena contracta from the flow through an orifice
a) inside the tank
b) directly outside orifice
c) past orifice where flow radius increases - Answers - b) directly outside orifice
Lab 6
What is the use of the pointer in lab 6? - Answers - To measure the diameter of the jet
Lab 6
What is the use of the pitot tube in lab 6? - Answers - To measure the stagnation
pressure of the jet
Lab 6
You predicted the flow rate through an orifice using continuity and bernoullis equation.
The actual flow rate was less than the predicted flow rate. What was the most probable
cause? - Answers - The predicted result disregarded all frictional effects
Lab 6
The volumetric flow rate, Q through an orifice is measured with the decreasing water
level, H in the tank. What is the relationship between the volumetric flow rate and the
pressure head in the tank?
a) Q∝H
b) Q∝H^2
c) Q∝√H
d) Q∝ log H - Answers - c) Q∝√H
Lab 6
A fluid passes through a sharp-edged orifice in the base of the tank. Two manometers
are installed: the manometer A connects to a Pitot tube which is positioned at the vena
, contracta of the fluid stream, the other manometer B connects to a pressure tapping in
the base of the tank. (a) Compare the heights of three water levels: manometer column
A and B, and water tank, C. - Answers - A<B=C
Lab 6
What is the reason of different heads in manometers?
a) Frictional head loss through an orifice
b) Acceleration of water due to gravity
c) elevation head difference
d) velocity head difference - Answers - Frictional head loss through an orifice
Lab 7
Which of the following is not an objective of Lab 7?
Measure the mean pressure distribution around the circumference of a circular cylinder
for three fluid speeds
Use a multi-tube manometer system to measure the pressures distribution
Measure the drag force exerted on the cylinder by means of a force dynamometer
Calculate the net force on the cylinder due to the pressure distribution
Nondimensionalize the data to see how scaling works - Answers - Measure the drag
force exerted on the cylinder by means of a force dynamometer
Lab 7
The coefficient of pressure is a non-dimensional number to scale pressure
measurements from a model to a full sized item. Which of the following is an advantage
of a non-dimensional number? Select all that apply.
It expresses the functional relationship between the variables in dimensionless terms.
It reduces the number of variables involved in a physical phenomenon.
The design curves can be developed from experimental data or direct solution of the
problem.
It allows to compare different systems by simplifying the problems in dimensionless
forms. - Answers - all answers are correct
Lab 7
The following plot shows the pressure distribution on a cylinder that is placed in a flow.
What is the main reason why the experimental data are different from the theoretical
calculation? (Pre Lab 7, Q4)
Theoretical results did not account for flow separation and viscous friction near the
body's surface.
The cylinder rotated fast about its axis.
The experiment was conducted at extremely low Reynolds number.
The discrepancy was introduced by assuming a uniform velocity profile approached the
cylinder. - Answers - Theoretical results did not account for flow separation and viscous
friction near the body's surface.
Lab 7
