Part 2: Some Classical Concepts and Equations in Fluid Mechanics Flashcards
True or False: Differential analysis can yield results for a few points in the flow field
False, differential analysis can yield results for ANY point in the flow field. This is why it is favoured over Control Volume Analysis that can only yield “global results”
What are the different types of fluid motion?
Transition ( no velocity gradient present), linear deformation, rotation , angular deformation
What is rotation?
the average angular velocity of two mutually perpendicular lines about a point
The existence of a streamline implies that continuity is ____________
Satisfied
True or False: Flow can occur across a streamline
False
The existence of a valid potential function, (Phi), means that the flow is ___________
Irrotational
Streamlines and Equipotential lines are _________ to each other
orthogonal
True or False: The velocity of flow is always perpendicular to the equipotential line
True
True or False: The velocity is always perpendicular any streamline
False, Velocity is parallel to the streamline
What is a Flow Net?
A flow net is a family of streamlines and equipotential lines drawn throughout a flow field.
Where is the pressure lowest on a flow net?
The pressure is lowest where the equipotential lines are the closest. This is also where the highest velocity is.
The difference between the water level upstream and the water level down stream is called _________
The Driving Head
True or False: A free vortex is irrotational
True
True or False: In a Forced vortex the highest velocity is on the outer edge.
True
What are the four Bernouilli assumptions?
- Inviscid fluid
- Steady Flow
- Incompressible Flow
- Flow is along a Streamline
In general, Potential Flow theory gives reasonable solutions to real fluid flow problems when:
1) the fluid is of low viscosity
2) The velocity is relatively high
3) The fluid is accelerating
True or False: For an inviscid flow there will be Shear stresses.
False, For inviscid flow there will be NO shear stress. There will however be normal stress due from pressure
The Naiver-Stokes equations are the basic differential equations describing _________
The flow of incompressible Newtonian Flow
True or False: Navier-Stokes law apply to both Laminar and Turbulent Flow
True
What is Plane Poiseuille Flow?
Poiseuille Flow is a steady, laminar flow between infinite horizontal, fixed, parallel plates. Flow occurs in the x-direction only. Maximum Velocity will occur at the centre between the points.
What is Couette Flow?
Couette flow is a steady, laminar flow between infinite horizontal, parallel plates. With flow occurring in the x-direction only and one plate moving.
What is Hagen-Poiseuille Flow?
Hagen Poiseuille Flow is a steady, laminar flow in a straight, horizontal, circular tubes of constant size.
