Fluid Dynamics Concepts Exam 1

A vertical cylinder is partially filled with a fluid. The container is rotated about its axis at a constant angular velocity for a long time. Identify the true statements about the fluid in motion. a. No shear stress occurs in the fluid. b. The liquid will move as a rigid body together with the container. c. Each fluid particle moves with a different angular velocity. d. The fluid is subjected to plastic deformation.

a,b

The force a flowing fluid exerts on a body in the flow direction is called the _____ force.

drag

If the speed of sound can be expressed by the equation c=√k×R×T2, the gas is a(n) _____ gas.

ideal

For Newtonian fluids, viscosity is _____.

independant of deformation

The international (SI) unit of thermal energy is _____

joule

A device that uses a fluid column to measure small pressure differences is called a

manometer

The SI units of kinematic viscosity are _____. Multiple choice question.

newton(meter)2

The pressure of a gas species in a mixture with other gases is the _____ pressure.

partial

If ρ and g represent the density of a fluid and the acceleration due to gravity, respectively, the weight of an enclosed liquid block of volume V is given by W = ___.

pgV

The speed of sound in a fluid is a function of the thermodynamic______ of that fluid.

properties

The temperature at which a pure substance changes phase, at a given pressure, is called the _____ temperature.

saturation

The flow energy or flow work is expressed as the product of pressure and ______.

specific volume

If the center of gravity of a floating body lies below the center of buoyancy, the body is said to be _____.

stable

The density of a substance is most likely dependent on _____.

temperature

When a fluid moves at constant velocity, the acceleration of a fluid is equal to

zero

At an absolute pressure of 1 standard atmosphere (1 atm), the saturation temperature of water is _____.

100 C

Consider a cylindrical beaker of height 50 mm, filled with water at rest. The gage pressure at a point 25 mm from the top surface is found to be 245 N/m2. The gage pressure at a different point 25 mm from the bottom surface will be _____ N/m2.

245 N/m2; Reason: The pressure in hydrostatics does not vary horizontally. Since the two points are at the same elevation, the value remains the same, which is 245 N/m2.

Standard atmospheric pressure is defined as the pressure produced by a column of mercury _____ under standard gravitational acceleration.

76.0 cm in height at 0°C

The upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces. This statement is known as _____.

Archimedes Principle

True or false: Pressure at the centroid of the submerged surface is the same as that at the center of pressure.

False

True or false: When the self-weight of an object exceeds the buoyant force, the object will float.

False, it will sink

What is the flow work?

It is the energy per unit mass needed to move the fluid and maintain flow.

Intensive properties

Temperature, pressure, and density

Absolute Pressure

The absolute pressure at any point equals the sum of the atmospheric pressure and the gage pressure Patm + ρgh.

What is Pascal's law?

The pressure applied in a closed fluid system is equally transmitted in all directions.

Extensive properties

Total mass, total volume, and total energy

The continuum idealization is valid as long as the size of the system is large relative to the space between the molecules.

True

True or false: Internal energy is only part of the total energy of a system.

True

Identify the systems that can be studied under fluid statics. a. The hydro-pressure acting on the wall of a dam b. The force acting on the surface of a nozzle during a fluid flow c. The forces acting on a floating boat d. The pressure developed by a hydraulic jack

a, b, d

The ideal gas equation of state is expressed as Pυ = RT, where P is the absolute pressure, υ is the specific volume, T is the thermodynamic temperature, and R is the gas constant. Select correct unit used for the temperature. (Check all that apply.) Multiple select question. a. Rankine (R) b. Fahrenheit (oF) c. Kelvin (K) d. Celsius (oC)

a, c