p0
Reminder
p=p0+h
h
p p h
If A and B are on a
common horizontal line are
connected by a single liquid pA = pB
0
The pressure at a point in a fluid does
not depend on directions
In fluids, pressure always acts
normal to a solid surface.
A
B
Static pressur
DAY 19: Boundary Layer
(after Couette
on the BLACKBOARD)
flat plate : let us neglect the shape of the
leading edge for now
flat plate boundary layer: in blue we highlight the region of the flow
where velocity is influenced by the presence of the solid sur
DAY 24: Flow in conduits
flow entering
a pipe
conduit: pipe, tube or duct completely filled with a flowing fluid (no free surface)
we can apply the energy equation: but, as usual, we have to estimate head losses.
Thats the challenge !
1) Flow regimes
Lam
Lift / drag
When an object is submerged in a flowing fluid, or the
object moves in a stationary fluid the fluid is forced to
flow around the object.
As a result, the object is subjected to forces
perpendicular and parallel to free stream velocity
Drag:
Day 24: Flow around objects
case 1) fluid flowing around a fixed
object (e.g. bridge pier)
case 2) object travelling within a fluid
(cars, ships planes)
two forces are exerted between the fluid and the object
related to:
Skin Friction (Ch9),
Drag, Lift (C
review pre-midterm2
Day 21
Definition of mass and volume flow rate
Q dQ Vn dA V dA
A
A
A
of course, for V normal to n and for V= constant
we come back to our first simple definition Q= VA
Generalized form for the mass flow rate
in case of constant veloc
DAY 16:
ENERGY
Chapter 7
REYNOLDS TRANSPORT
THEOREM
for a system with discrete entrances and exits
B is an extensive property
b=dB/dM is the intensive counterpart
d
bd mb OUT mb IN
dt
dt CV
dBsys
REYNOLDS TRANSPORT
THEOREM & Mass
for a system with disc
Chapter 4: description of fluids in motion
First: fluid motion is defined by the velocity vector v = v(x,y,z)
steady motion:
the flow velocity does not change in time
particular streamline
the streamline is a curve that is
parallel (or tangent) to the vel
Image from Wikipedia.com
Osborne Reynolds
(23 August 184221 February 1912)
Transition from laminar to turbulent flow
Reynolds number
Reynolds stresses
Reynolds-averaged Navier Stokes equations
Reynolds transport theorem
given u=U+u, with U=<u>
Reynold
DAY 17:
Energy Grade Lines &
Hydraulic Grade Lines
EGLs & HGLs
HYDRAULIC GRADE LINE HGL
Graphical
representation of p
(often p G z
)
Recall,
z
if we tap in piezometers,
at each point i, the fluid level will
rise to a height of
pi
zi
HGLS ARE LIKE THE
Fluid Mechanics 3502
Day 2
Fluid Properties Part 2
Solid-Liquid-Gas
Solid under shear vs Fluid under Shear
Density / Specific Weight
Compressible vs. Non-Compressible (contd)
Viscosity
Newtonian vs. Non-Newtonian Fluids
Surface Tension
Vapor Pressure
Summ
Rotation and vorticity
V magnitude increases
V direction changes
note:
the rotation of a fluid element
has to be quantified at a small scale
Consider a fluid element undergoing shear
y
under a linear velocity profile
(constant shear dU/dy)
a small fluid e
Chapter 4: description of fluids in motion
First: fluid motion is defined by the velocity vector v = v(x,y,z)
steady motion:
the flow velocity does not change in time
particular streamline
the streamline is a curve that is
parallel (or tangent) to the vel
Fall, 2016
Lian Shen
ME5332
Handouts #2
Introduction
1 in the textbook.
What are fluids and fluid mechanics?
1.3 in the textbook.
A fluid is a substance that deforms continuously under an applied shear stress,
however small.
See whiteboard for discussion.