Fluid Mechanics
(AME 3810)
Dr. Nasser Mohamed Shelil
Assistant Professor, Mechanical Engineering Dept.,
College of Applied Engineering, King Saud University
B.Sc. & M.Sc. , Suez Canal University; PhD, Cardiff University/UK
Course Contents
Chapter 1: Introduction & Dimensions and Units
Chapter 2: Fundamental Concepts in Fluids
Chapter 3: Fluid Statics
Chapter 4: Basic Equations of Fluid Flow
Chapter 5: Applications for Internal Incompressible Viscous Flow
Chapter 6: Applications for External Viscous Flow
Chapter 7: Momentum Equation
Chapter 8: Dimensional Analysis
Applied Mechanical Engineering Program
Fluid Mechanics Contents 2
References
1. R.W. Fox, A.T. McDonald, and P. J. Pritchard, “Introduction to Fluid
Mechanics”, John Wiley & Sons, 7th Edition, 2008.
2. P.J. Pritchard and J.C. Leylegian, “Introduction to Fluid Mechanics”,
8th Ed., 2011.
3. J.F. Douglas, J. M. Gasiorek, J. A. Swaffield and Lynne B. Jack “Fluid
Mechanics”, 5th. Ed., 2006.
4. B. R. Munson, D.F. Young, T.H. Okiishi, and W.W. Huebsch.
“Fundamentals of Fluid Mechanics”, 6th Ed., 2009.
5. F. White, “Fluid Mechanics”, 4th. Ed.,
Applied Mechanical Engineering Program
Fluid Mechanics References 3
Assessment
Assessment task
(e.g. essay, test, group project, Week due %
examination etc.)
1 Homework Assignments Every weeks 10
2 Attendance and Participation Every weeks 10
3 Mid Term Exam 8 10
4 Quizzes … 10
5 Laboratory reports Every weeks 10
6 Laboratory Tests … 10
Final Exam 17 40
Applied Mechanical Engineering Program
Fluid Mechanics Assessment 4
Applied Mechanical Engineering Program
Fluid Mechanics Assessment 5
Chapter 1:
Introduction & Dimensions and Units
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 6
Fluid
A fluid is a substance which deforms continuously
under the action of shearing forces, however small
they may be.
Deformation caused by shearing forces
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 7
Matter
Solid Fluid
Liquid Gas
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 8
Mechanics
Statics Dynamics
Kinematics Kinetics
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 9
Classification Of Mechanics
Statics:
Statics is the branch of mechanics which deals with forces and
their effects while acted upon bodies which are at rest.
Dynamics:
Dynamics is the branch of mechanics which deals with forces and
their effects while acted upon bodies which are in motion.
Kinematics:
Kinematics is the branch of mechanics which deals with motion
parameters without considering the forces responsible for motion.
Kinetics:
Kinetics is the branch of mechanics which deals with motion
parameters as well as forces responsible for motion.
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 10
Units & Properties
Units
SI (metric) English system
kilogram (kg) pound (lb)
meter (m) foot (ft)
second (s) second (s)
lb = 0.45359 kg
ft = 0.3048 m
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 11
The seven fundamental (or primary)
dimensions and their units in SI
Dimension Unit
Length meter (m)
Mass kilogram (kg)
Time second (s)
Temperature Kelvin (K)
Electric current Ampere (A)
Amount of light candela (cd)
Amount of matter mole (mol)
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 12
Length m Work
Mass kg Heat
Time s Energy
Area m2 Power
Volume m3
Velocity
Acceleration
Density
Specific Volume
Mass flow rate
Discharge
Pressure
Force
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 13
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 14
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 15
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 16
Convert:
100 km/hr → m/s.
5 m2 → ft2 .
2 kg/s → lb/min.
9.81 m/s2 → ft/s2.
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 17
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 18
Pressure
P = F/A ≡ N/m2 (Pa)
Pgage = Pabs – Patm
Pvac = Patm – Pabs
1 bar = 105 Pa = 0.1 MPa = 100 kPa
1 atm = 101,325 Pa = 101.325 kPa = 1.01325 bars
1 kgf/cm2 = 9.807 N/cm2 = 9.807x104 N/m2 = 9.807x104 Pa
1 atm = 14.696 psi
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 19
Temperature
The Kelvin scale is related to the Celsius scale by
T (K) = T ( °C) + 273.15 (1)
The Rankine scale is related to the Fahrenheit scale by
T (R) = T ( °F) + 459.67 (2)
It is common practice to round the constant in Eq. 1 to 273 and that
in Eq. 2 to 460.
The temperature scales in the two unit systems are related by
T (R) = 1.8 T (K)
T (F) = 1.8 T ( °C) + 32
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 20
DENSITY
The density of a substance is that quantity of matter
contained in unit volume of the substance.
ρ = m/V [kg/m 3] Note:
Specific volume (υ):
υ = 1/ρ [m3/kg]
Specific Weight
γ = W /V [N/m 3]
γ=ρg [N/m 3]
Relative Density
s = ρ/ρw = γ/γw [-]
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 21
Viscosity
The dynamic viscosity
μ : The dynamic viscosity [Pa.s]
Poise =0.1 Pa.s
The kinematic viscosity
stokes (St); [104 St = 1 m2/s]
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 22
Equation Of State Of A Perfect Gas
Pv = RT
PV = mRT v =V /m
PV = NMRT m = NM
PV = NR T R = MR
Pv = R T v =V / N
• where,
P = absolute pressure, N/m2
V = volume, m3 v = specific volume, m3/kg
v = molar specific volume, m3/kmol
N = No of kmoles m = NM= mass, kg
T = absolute temperature, K
R = Universal gas constant, J/kmol.K R = gas constant, J/kg.K
M = Molecular Weight, kg/kmol = R /M
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 23
Convert:
220 kPa → kg/cm2 & bar & psi
30 oC → F & K & R.
20 Pa.s → lb.s/ft2.
4 m3 → gallon & ft3.
Applied Mechanical Engineering Program Chapter 1
Fluid Mechanics Introduction 24
