Fluids Quiz

In the entrance region of the pipe, the velocity profile changes with location along the pipe.

True

In the fully developed flow region, the pressure decreases linearly with x (length along the pipe)

True

In the non-fully developed flow regions i.e. entrance region - Fluid accelerates or decelerates as it flows.

True

The entrance length can't exceed the pipe length.

False

The velocity is constant as we move radially outwards from the centerline of the pipe to the pipe wall, for fully developed flow.

False

Turbulent flow shear stress is smaller than laminar flow shear stress because of the irregular, random motion

False

There is no rigorous theoretical treatment of turbulent flow.

True

What is the main driving force for pipe flow?

Pressure Gradients

Ethyl alcohol is flowing through a 25cm diameter horizontal pipeline. When the velocity is .17m/s, what is the Reynolds Number?

28214

The figure shows a system for pumping water from a canal to an overhead tank. The pipe line is 0.1 m in diameter and the total length of the pipeline is 60m. When the flow velocity is 3 m/s, the friction factor is 0.02. Ignoring minor losses, the energy added by the pump (m) under these conditions is most nearly?

45.5m

Crude oil of SG=8.82 is flowing at a velocity of 8.15 m/s through a pipe of diameter 1.25m fiction faction of 0.02. The head loss due to viscous effects over 1000m of pipe is most near:

5.4m

Water flows steadily through a horizontal circular pipe. Which curve most correctly describes the pressure change through the pipe as the length is increased?

D

During the entrance region, the pressure drop decreases linearly with x (distance along the pipe).

False

During the entrance region, the boundary layer:

Grows

Water is flowing in a pipe. Which is the correct statement about the effect of an increase in the Reynolds Number of the flow:

If the flow is laminar, it could become turbulent.

There is a steady laminar flow of water in a horizontal pipe of length l. A the volumetric flowrate increases, the pressure drop over the length l:

Increases

In the fully developed region of the pipe, the velocity profile:

Is equal across any section of the pipe

In turbulent flow the larger the turbulence intensity the ___________ the fluctuations in velocity will be:

Larger

The magnitude of the pressure gradient, is ___________ in the entrance region than the fully developed region.

Larger

For fully-developed viscous flow in a horizontal pipe, which of the following is true:

Pressure Forces are balance by shear forces

For what range of Reynolds Numbers will flow in a round pipe be laminar?

Re < 2100

When measuring the average velocity of the flow within the pipe system shown below, which regions of the pipe systems are the most optimal locations for the placement of a flow measurement device.

Regions 2-3 and Regions 5-6, Fully developed regions

A horizontal pipe is tilted so that not the flow is at a downward angle, the pressure change needed to achieve the same flow rate would be:

Smaller

For a steady uniform flow of an incompressible liquid that enters a pipe, which of the following is true for the entrance region?

The maximum velocity increases with distance from the entrance

Considering fully developed laminar flow, shear stress is a maximum at:

The wall

For fully developed laminar flow, shear stress varies linearly with the radial position in the pipe, r, from 0 at the centerline to the max at the wall.

True

For a given flow, the Reynolds number is 13276. What type of flow is this?

Turbulent

Basic horizontal pipe flow is governed by:

Viscous and pressure forces

What causes fluid layers to stick to the wall (i.e. the no slip condition)?

viscous effects