Fluids Final

Pressure

When analyzing hydrostatic forces on a plane surface, Yr and Xr represent the location of the center of ___________.

Atmospheric

When analyzing hydrostatic forces on submerged surfaces, the ______________ pressure can be subtracted for simplicity when it acts on both sides of the structure.

Weight

Specific __________ is the weight of a substance per unit volume.

Motion

We can describe the flow of a fluid in terms of the _______ of fluid particles rather than individual molecules.

Lagrangian

The _____________ approach follows a fluid particle instantaneously to measure and calculate it’s properties.

Eulerian

The __________ approach observes a fixed volume in space (a control volume) and measures/calculates the properties of fluid particles that pass through space.

Eulerian

The ______________ approach to finding a fluids properties is often less tedious and, therefore, more common and practical.

Continuum

______________ assumption assumes that infinitesimal particles are so tightly packed together that a description of a fluid property can be given as a function of the fluids location.

Function

Field representation is the method to describe the fluid property. In doing so, it describes the fluid property as a _________ of the location of the fluid.

Field

The distribution of velocity is called the velocity __________. We also have one for pressure, acceleration, etc.

Flow

A _________ field is the collection of all the flow properties (V, P, T, etc.)

Speed

The magnitude of a fluids velocity is also called the __________ of the fluid.

Flowrate

Think of the Eulerian approach as the __________ at a given location as a function of time.

Position

Think of the Lagrangian approach as the ___________ of a given particle as a function of time.

Steady

________ flow means that the velocity at a given point in space does not vary with time.

Unsteady

___________ flow means that the velocity at a given point in space varies with time.

Unsteady

_________ flow occurs in turbulent flow and is absent from laminar flow.

Steady

_________ flow means the values of all fluid properties at any fixed point in space are independent of time.

F

In steady flow, the properties do not change with time at different locations. (T/F)

Streamline

A _____________ is a line that is everywhere tangent to the velocity vector.

Streakline

A ________________ consists of all particles in a flow that have previously passed through a common point.

Pathline

A ___________ is the line traced out by a given particle as it flows from one point to another.

T

For steady flow, a pathline and streakline are the same as a streamline. (T/F)

F

For unsteady flow, a pathline and streakline are the same as a streamline. (T/F)

Pathline

A ___________ is the trajectory of an individual fluid particle.

Streakline

A _______________ is the locus of all particles that pass through one location at different times. It connects the ends of several particle path lines.

Streamline

A ___________ is a curve tangent to the velocity vectors at a given time instant.

Streamline

The equation of a _________ is dy/dx or v/u.

Acceleration

The eulerian description of the _____________ field is a function of position and time, without actually following any particular particle.

Material

The _________ derivative concept is very useful in analysis involving various fluid parameters.

Local

The time derivative portion of the material derivative formula is termed the ___________ derivative.

Time

The ________ derivative portion of the material derivative represents effects of the unsteadiness of the flow.

Local

The time derivative of the acceleration material derivative is called __________ acceleration.

Convective

The portion of the material derivative represented by the spatial derivatives is termed the ___________ derivative.

Convective

The __________ derivative represents the fact that a flow property associated with a fluid particle may vary because of the motion of the particle from one point in space where the parameter has one value to another point in space where its value is different.

Fluid

A __________ is a type of matter that is relatively free to move, deform, and interact with its surroundings.

System

A __________ is a collection of matter of fixed identity (always the same atoms or fluid particles), which may move, flow, and interact with its surroundings.

Control Volume

A ________________ is a volume in space (a geometry entity independent of mass) through which fluid may flow. (2 Words)

System

A ____________ may continually change in shape and size but will always contain the same mass.

Control Volume

A ______________ matter may change with time as fluid flows through it. The amount of mass may change as well. (2 Words)

Control Volume

The approach to a _______________ is similar to approaching a problem with the eulerian method. (2 Words)

Reynolds

The ___________ transport theorem is an analytical tool to shift from one representation to the other.

Extensive

In B=mb, the parameter B is an ________ property.

Intensive

In B=mb, the parameter b is termed an ___________ property.

Extensive

Most of the laws governing fluid motion involve the time rate of change of an _________ property of a fluid system.

Reynolds

The __________ transport theorem provides the relationship between the time rate of change of an extensive property for a system and that for a control volume.

Material

The ___________ derivative is also called the total derivative or substantial derivative.

True

In a control volume, even if the flow is steady, there can be acceleration if velocity changes spatially. (T/F)

Volume

A control _____________ is a region of observation (a eulerian concept).

Surface

A __________ surface surrounds the control volume (boundary of the CV / faces of the shape).

Surface

The integral across the control __________ represents the net flowrate of the parameter B across the entire control surface.

Material

The physical interpretation of the ____________ derivative is that it provides the time rate of change of a fluid property associated with a particular fluid particle as it flows.

True

The material derivative can be applied to scalars and vectors. (T/F)

Relative

A moving control volume has _________ velocity to account for.

Relative

The ____________ velocity is the fluid velocity relative to the moving control volume (the fluid velocity seen by an observer riding along on the control volume).

Absolute

The ____________ velocity is the fluid velocity as seen by a stationary observer in a fixed coordinate system.

Relative

The _____________ velocity is the difference between the absolute velocity and the velocity of the control volume.

System

A ________ is a collection of fluid particles of fixed identity. A lagrangian concept for a particle tracking approach. It is the collection of the SAME fluid particles!

Connects

The Reynolds Transport Theorem ________ the lagrangian and eulerian approaches.

Continuity

The ___________ equation is the control volume expression for conservation of mass.

T

Fluid moves from high to low pressure, always. (T/F)

Energy

___________ conservation is a method utilized for mechanical systems involving fluid flow.

Pumps

__________ (or compressors) add energy to fluids.

Turbines

_________ remove energy from fluids.

Energy

Assumptions for ___________ conservation:


1. Single Inlet and Outlet - One Mdot
2. 1D Flows - Vin and Vout
3. Steady Flow/Operation (Rate of Energy in = Rate of Energy out)
4. Incompressible Fluids - Constant Density (rho)
5. No Heat Transfer!

Opposite

In a force conservation problem, the force experienced by the fluid is the __________ of the force experience by the nozzle.

Opposite

In a force conservation problem, an anchoring force of a vane is the __________ of the force experience by the nozzle.

Same

In a force conservation problem, an anchoring force of a vane is the __________ of the force experience by the fluid.

T

We only get a “big picture” from the integral forms of the conservation laws like mass conservation, momentum, and energy (T/F).

Mass

The gauss divergence theorem gives us a closer look at the __________ conservation integral form.

Navier-Stokes

The ___________________ equations are only solvable with simple problems or computational fluid dynamics (CFD).

Reynolds

_______________ number is an important quantity in any fluid flow because it determines if the flow is laminar or turbulent.

Internal

Pipes or ducts represent a case of ____________ flow.

F

Reynolds number has dimensions (T/F).

Laminar

____________ flow means that the flow is smooth, no mixing occurs, and a low reynolds number is observed (below 2000).

Turbulent

____________ flow means that the flow is chaotic, mixing occurs, and a high reynolds number is observed (above 4000).

Transition

A reynolds number between 2000 and 4000 represents a fluid ______________.

Pumps

In a pipe, we need to supply high pressure to counteract viscous friction. We do this by adding _____________, which consume energy.

Booster

We add pumps to supply high amounts of pressure in pipes to counteract viscous friction. These pumps are commonly called _____________ pumps.

Laminar

For ______________ flows, we can solve Navier-Stokes equations.

Turbulent

For ______________ flows, we cannot solve Navier-Stokes equations.

Moody

A turbulent flow requires the friction coefficient to be read from a ___________ chart.

Hydraulic

A non-circular pipe or duct can be solved using the same methods as circular pipes or ducts, however, we need to use a _____________ diameter.

Bend

A _________ in the pipe will require calculating for major and minor losses.

Loss

A pipe bend has a ___________ coefficient, K.

Dimensional

_______________ analysis and modeling can reduce the amount of parameters we are dealing with when designing.

L(T^-1)

MLT analysis for velocity is ________.

L(T^-2)

MLT analysis for acceleration is ________.

ML(T^-2)

MLT analysis for force is ___________.

M(L^-1)(T^-2)

MLT analysis for pressure is ____________.

M(L^2)(T^-2)

MLT analysis for energy is _____________.

M(L^2)(T^-3)

MLT analysis for power is ___________.

Mass

M in MLT stands for _________.

Length

L in MLT stands for __________.

Time

T in MLT stands for _______.

Buckingham

___________________ pi theorem means we can simplify a problem involving n parameters by rewriting it in terms of (n-j) dimensionless parameters called ‘pi’ terms, where j is the number of fundamental dimensions (M,L,T) involved in the problem.

First

The ___________ step of the buckingham pi theorem is to list all the parameters involved, letting n represent the number of parameters.

Second

The ________ step of the buckingham pi theorem is to list the dimensions of all parameters in terms of primary dimensions (let j be the number of primary dimensions).

Third

The _________ step of the buckingham pi theorem is to select a set of j ‘repeating’ parameters that includes all of the primary dimensions.

Fourth

The _________ step of the buckingham pi theorem is to set up the dimensional equations, combining the repeating parameters selected in the previous step with each of the other parameters in turn, to form dimensionless groups (there will be n-j equations).