Chapter 4 Flashcards
What is a steady flow?
The velocity at a given point does not vary with time.
What is an unsteady flow?
Velocity at a given point in space varies with time
What is a streamline?
A line drawn through the flow field (at any given moment of time) which is everywhere tangent to the velocity field vectors.
Flow where all properties are independent of time is called?
Steady flow
Properties in this type of flow can vary with respect to time.
Unsteady flow
Lagrangian description of motion
Focuses attention on an idividual fluid particle and follows its motion to see how properties associated with the particle change with a function of time
Eulerian description of motion
Focuses attention on a point in space and studies flow past that point
Pathlines
Trajectory or path of a single fluid particle over some period of time
Streamline
Imaginary curves in the flow which at any instant of time are tangent of the velocity vectors of the fluid particles (everywhere tangent to the velocity field)
Streakline
Consists of all particles in a flow that have previously passed through a common point.
Streamlines, pathlines, and streaklines are all the same for _________ .
Steady flow
Control volume
Volume in a space “isolated” for study (fluid can enter or leave a control volume)
A system
Fixed quantity of Mass “isolated” for study
Intensive property relationships for a system of fixed amount of mass is called
Extensive = B
b = (p, T, rho, etc.)
Intensive property
A line traced out by a given particle as it flows from one point to another.
Pathline
How does the Eulerian description describe the acceleration field?
As a function of position and time without actually following any particular particle.
What is the Material Derivative?
It is used to describe time rates of change for a given particle.
