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Fluid statics of fluid mechanic
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1
Fundamental of Fluid Mechanics (Lecture 3)
Dr.Eng Denny Widhiyanuriyawan, ST, MT
Department of Mechanical Engineering,Brawijaya University
Malang, Indonesia
Email: [email protected]
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Chapter 3
Fluid Statics
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Main Topics
The Basic Equations of Fluid StaticsPressure Variation in a Static FluidHydrostatic Force on Submerged SurfacesBuoyancy
Forces : Body Force
Surface Force
Body Forces : - Gravity force
- Electromagnetic Force
- Corriolis Force
- Centrifugal Force
Surface Forces : - Pressure Force
- Viscous Force (ShearForce)
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The Basic Equationsof Fluid Statics
Body Force (gravitasi force yg sering digunakan dalam MF)
Jika elemen fluida dalam bentuk kubus maka dV=dx.dy.dz
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The Basic Equationsof Fluid Statics
Surface Force
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The Basic Equationsof Fluid Statics
Surface Force
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The Basic Equationsof Fluid Statics
Surface Force
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The Basic Equationsof Fluid Statics
Total Force
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Newton’s Second Law
dadmadF
Fluida static a = 0
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The Basic Equationsof Fluid Statics
Newton’s Second Law
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The Basic Equationsof Fluid Statics
0
x
p
0xg
0
y
p
0yg
gz
p
ggz
Depan belakang
kanan kiri Atas bawah
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The Basic Equationsof Fluid Statics
Pascal’s Law
s
y
sins
x
cos
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The Basic Equationsof Fluid Statics
zypApF xxx ABFE ..
zxpApF yyy CDEF ..
zspApF sss ABCD ..
Surface Force Body Force
- mg = - Vg = - (dxdydz/2) g
syx ppp Pascal’s Law
Buktikan
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The Basic Equationsof Fluid Statics
Vertically
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The Basic Equationsof Fluid Statics
Horizontally
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The Basic Equationsof Fluid Statics
Generally
Cari Kesetimb
angan gaya2nya
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The Basic Equationsof Fluid Statics
Pressure-Height Relation
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Pressure Variation in aStatic Fluid
Incompressible Fluid: Manometers
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Pressure Variation in aStatic Fluid
Compressible Fluid: Ideal Gas
Need additional information, e.g., T(z) for atmosphere
Hydrostatic Condition: U.S. Standard AtmosphereIdealized Representation of the Mid-Latitude Atmosphere
Linear Variation, T = Ta - z
Isothermal, T = To
Standard Atmosphere is used in the design of aircraft, missiles and
spacecraft.
Stratosphere:
Troposphere:
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Pressure Variation in aStatic Fluid
In the sea level surface p0, 0 and z0 = 0. • po = 101,303 Pa (14.696 lb/in2) = lapse rate (koefisien muai untuk
udara) = 0,00650 K/m. For U.S Standard AtmosphereTo = 15oC = 288.15 K (59oF or
518.67oR)
Troposphere
Rg
o T
zpp
01
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Pressure Variation in aStatic Fluid
Stratosphere
Temperature constant
T=Tc=216,7 K=319,1 oR
Zc=11 km (36000ft)
Pc=22600 Pa (3,28 lb/in2)
c
c
RTzzg
cepp
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Pressure Variation in aStatic Fluid
Ionosphere
DISCONTINUM FLUID
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Hydrostatic Force on Submerged Surfaces
Plane Submerged Surface
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Hydrostatic Force on Submerged Surfaces
Plane Submerged Surface
We can find FR, and y´ and x´,by integrating, or …
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Hydrostatic Force on Submerged Surfaces
Plane Submerged Surface• Algebraic Equations – Total Pressure Force
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Hydrostatic Force on Submerged Surfaces
Plane Submerged Surface• Algebraic Equations – Net Pressure Force
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Hydrostatic Force on Submerged Surfaces
Curved Submerged Surface
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Hydrostatic Force on Submerged Surfaces
Curved Submerged Surface• Horizontal Force = Equivalent Vertical Plane Force• Vertical Force = Weight of Fluid Directly Above
(+ Free Surface Pressure Force)
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Buoyancy
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Buoyancy
For example, for a hot air balloon (Example Problem 3.8):
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Examples 3.2
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Examples 3.2
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Examples 3.2
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Examples 3.2
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Examples 3.2
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Examples 3.8
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Examples 3.8
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Examples 3.8
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Examples 3.8
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Examples 3.8
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Examples 3.9
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Examples 3.9
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Examples 3.9
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Examples 3.9
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Examples 3.36
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Examples 3.36
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Examples 3.36
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Examples 3.36
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Examples 3.36
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Practice -q3.77 (optional)
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Project (3) – q 3.60