Fluids Multiple choice

B

A potential flow vortex is rotational. A. True B. False

B

A fluid flows steadily through a pipe with a uniform cross-sectional area. The density of the fluid decreases to half its initial value as it flows through the pipe. The correct statement about the average velocity V is A. V2 equals ½ V1 B. V2 equals 2V1 C. V2 equals V1

B

A 1/10th scale model of an airplane is tested in a wind tunnel. The Reynolds number of the model is the same as that of the full-scale airplane in the air. The velocity in the wind tunnel is then A. the same as that of the full-scale airplane. B. 10 times that of the full-scale airplane. C. 100 times that of the full-scale airplane. D. 1/10th that of the full-scale airplane.

B

A Newtonian fluid flows under steady, laminar conditions through a circular pipe of diameter 0.16 m at a volumetric rate of 0.05 m3/s. Under these conditions, the maximum local velocity (m/s) at a section is most nearly A. 2.0 m/s B. 5.0 m/s C. 3.0 m/s D. 2.5 m/s

B

A hurricane is an example of a ______. A. Forced vortex B. Free vortex C. Source D. Sink

D

A jet of water leaves the nozzle at the end of a hose as shown below. The nozzle and hose are held in place by the support. Note that the length of arrow represents the magnitude of the velocity. Force Fx is exerted by the support to the water jet A. direction of Fx is indeterminate B. Fx =0 C. Fx<0 D. Fx> 0

C

A rectangular tank of water open to the atmosphere is shown below. The depth of the water is h. The figure that best describes the location of the resultant force (center of pressure) on the left hand side of the tank is

B

A short pipe with a nozzle at an angle from the vertical is attached to the tank of water as shown below. The flow is frictionless. The figure that best describes the flow of water from the nozzle is

C

A tank is filled with a liquid and the surface is exposed to the atmosphere. Which of the following accurately represents the absolute pressure distribution on the right-hand side of the tank?

A

A tank is filled with a liquid and the surface is exposed to the atmosphere. Which of the following accurately represents the gage pressure distribution on the right-hand side of the tank?

A

A tank of water open to the atmosphere with a depth h is shown below. The left side of the tank is a rectangular shape and is at an angle. The location yH of the horizontal force FH on the rectangular plate is given by: A. yH=h/3 B. yH=L/3 C. yH=h/2 D. yH=L/2

B

A two-dimensional gate is submerged in water. The figure that best represents the pressure distribution of the water on the left hand (water) side of the gate is

D

Air flows into a round pipe that is at an angle β with respect to the wall as shown below. The correct expression for the mass flow rate of the air through the pipe is A. ρVA tan(β) B. ρVA cos(β) C. ρVA sin(β) D. ρVA

B

Air flows through a doorway at an angle α as shown below. The correct expression for the mass flow rate of the air through the doorway is A. ρVA cos(α) B. ρVA sin(α) C. ρVA D. ρVA tan(α)

A

Fluid flows steadily through the control volume (shown with dotted lines) shown below. The velocity components are in the direction shown, and force is positive in the x-direction. The force on the fluid in the control volume is.

B

For steady, laminar flow between fixed parallel plates, the velocity profile is parabolic in shape as shown in the figure. The shear stress is given by A. has a negative value. B. has a zero value. C. has a value equal to the wall shear stress D. has the maximum value.

B

For the flow of a Newtonian fluid The shear stress is proportional to A. du/dx B. du/dy C. du/dt D. u

B

How could flow around a half body be obtained? A. By adding a vortex to a uniform flow. B. By adding a source to the uniform flow. C. By adding a sink to a uniform flow.

B

If the flow is steady, there can be a difference in velocity at different locations in the flow field, True or False A. False B. True

E

If the viscosity of the fluid is zero in the above problem and the fluid slip at the boundary is infinite, which of the following are true? A. The magnitude of the fluid force on the lower plate is zero B. The velocity in the fluid is zero C. The upper plate will continue to accelerate as long as the force F is applied D. All of the above E. A and C

D

The Reynolds Transport Theory A. allows us to convert the basic equations from a system to a control volume B. applies to steady and unsteady flow situations C. applies to conserved properties D. all of the above

D

The Reynolds number can be interpreted as A. the ratio of kinetic energy to viscous forces. B. the ratio of momentum flux to viscous forces. C. the ratio of viscous to inertial forces. D. the ratio of inertial to viscous forces.

B

The behavior of a fluid under the action of a constant shear force is shown below. The upper plate moves to the right under the action of a constant force F and the lower plate is stationary. The dotted lines indicate the location of the fluid particles at three different times In terms of the definition of a fluid, what is the difference in the velocity of the fluid particles between time t1 and time t2? A. The velocity at t2 is greater than the velocity at t1 B. There is no difference C. There is not enough information to determine whether there is a difference or not D. The velocity at t2 is less than the velocity at t1

C

The definition of a fluid is A. a substance that fills the volume of the container in which it is placed. B. a substance that deforms under a normal stress. C. a substance that deforms continuously under the action of a shearing stress. D. a substance in the liquid phase. E. a substance that flows because of the pressure that is acting on it.

A

The material derivative of a property such as pressure is given as The material derivative of pressure is used to determine A. the variation in pressure seen by an observer moving with the flow. B. the variation in pressure seen by an observer at a specific location.

A

The same pipe is used to carry both air and water. For the same fluid velocity and friction factor for the air and water flows A. the head loss for the air flow equals that for the water flow. B. the head loss for the air flow is greater than that for the water flow. C. the head loss for the water flow is greater than that for the air flow

B

The same pipe is used to carry both air and water. For the same fluid velocity and friction factor for the air and water flows A. the pressure drop for the air flow is greater than that for the water flow. B. the pressure drop for the water flow is greater than that for the air flow. C. the pressure drop for the air flow equals the pressure drop for the water flow

A

The standard unit normal vector A. is normal to the control surface pointing outward. B. is normal to the control surface pointing inward. C. is a tangent to the control surface.

A

The statement that best describes viscosity is A. viscous forces occur because of interactions between molecules as a fluid moves. B. when a fluid isn't moving it doesn't have viscosity. C. viscous forces act normal to the surface the fluid is flowing over.

C

Two systems filled with a liquid are shown below. The tubes on the left have the same force applied to pistons with the same area. The tubes on the right are open to the atmosphere and have different areas as indicated A. h2=h1/3 B. h2=9h1 C. h2=h1

C

Two tanks filled with air and connected by water-filled manometers are shown below. The water levels are as shown. Using the height of water column above the 0" line, the gage pressure of Tank A could be expressed as: A. PA equals +3" B. PA equals +1" C. PA equals +0" D. PA equals -1"

B

Water flows through a duct of square cross section as shown in the figure below with a constant, uniform velocity of V=15 m/s. Determine the flowrate in the duct. A. 7.5 m3/s B. 3.75 m3/s C. 15 m3/s D. 3750 kg/s

D

Water flows without friction through a constant diameter circular pipe that is tilted upward. The curve that best describes the static pressure distribution for the pipe is

A

Water flows without friction through a horizontal pipe and enters a section where the cross sectional area is smaller. The velocity profile is uniform at sections 1 and 2. The correct statement about the static pressure p2 relative to p1 and the velocity V2 relative to V1 along the streamline down the center of the pipe is A. p2 < p1 and V2 > V1. B. p2 > p1 and V2 > V1. C. p2 < p1 and V2 < V1. D. p2 > p1 and V2 < V1.

C

Water flows without friction vertically downward through a pipe and enters a section where the cross sectional area is larger. The velocity profile is uniform at sections 1 and 2. The correct statement about the static pressure p2 relative to p1 and the velocity V2 relative to V1 along the streamline down the center of the pipe is A. p2 < p1 and V2 < V1. B. p2 < p1 and V2 > V1. C. p2 > p1 and V2 < V1. D. p2 > p1 and V2 > V1

B

Water is contained between two sets of large plates as shown below. The upper plates are pulled at the same velocity and the flow is laminar. The height of the space on the right is twice that of the height on the left. The correct statement about the relation between the force required to pull the upper plate relative to the lower plate is A. F2=F1 B. F2=0.5F1 C. F2=4F1

C

What term is used when the fluid pressure is reduced to the vapor pressure? A. Differential B. Bernoulli effect C. Cavitation

C

What value must the Reynolds number be lower than to be considered laminar for pipe flow? A. 20,000 B. 500,000 C. 2,100

D

When a Newtonian fluid flows under a fully developed, a steady, laminar condition through a circular pipe of constant diameter, which of the following is NOT a correct conclusion? A. The velocity gradient at the centerline of the pipe is zero. B. The shear stress at the centerline of the pipe is zero. C. The maximum velocity at a section is twice the average velocity at that section. D. The velocity will decrease along the length of the pipe.

D

When comparing solids to fluids, the following is true A. For elastic solids, the stress must be normal. For Newtonian fluids, the stress must be shear. B. For elastic solids, the stress must be shear. For Newtonian fluids, the stress must be normal. C. For elastic solids, stress is linearly related to strain rate, for Newtonian fluids, stress is linearly related to strain. D. For elastic solids, stress is linearly related to strain, for Newtonian fluids, stress is linearly related to strain rate

B

Which shear stress is dominant in the viscous sublayer? A. Turbulent B. Laminar C. There is no dominant shear stress

A

You measure your weight on a scale in your bathroom. It reads 150 pounds. A. Your mass is 150/32.17 slug. B. Your mass is 150/32.17 lbm. C. Your mass is 150*32.17 lbm