Pertemuan 03 - 04
Hydrostatics 1
Fundamental Principles
•
•
Deals with fluids either at rest or in
motion in such away that there is no
relative motion between adjacent
particles.
The term pressure is used to indicate the
normal force per unit area at a given
point on a given plane within the fluid.
Bina Nusantara
• Focus :
1.
2.
3.
4.
Properties of Fluid
Pressure
Measurement of Pressure (Manometers)
Hydrostatics Flow  Vertical,
Horizontal , Inclined, Curved
5. Bernoully
6. Buoyancy, stability of submerged and
floating bodies
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Fluid Pressure (hydrostatics 1)
• The force per unit area acting on a real or imaginary surface within
a fluid is called intensity of pressure or simply pressure, p.
• Pressure at Point
• Pascal’s Law
• Measurement of Pressure ( Manometers)
Bina Nusantara
Fluid Pressure at a Point
• The force per unit area acting on a real or imaginary surface within
a fluid is called intensity of pressure or simply pressure, p.
• The force exerted by the surrounding fluid on the area dA will
always perpendicular to the surface dA.
• Mathematically : p = dF/dA
- if the forced is uniformly distributed over the area (A)
p = F/A = Force/Area
• So, Force or Pressure Force , F = p x A
Bina Nusantara
Pascal Law
•
The pressure at a point in static fluid is equal in
all direction
C
q
px.dy.1
q
A
py.dx.1
•
Bina Nusantara
Forces on a fluid element
• The forces acting on the element are :
1. Pressure forces formal to the surfaces
pz.ds.1 2. Weight of element in the vertical direction
Forces on the face AB = px x dy x 1
AC = py x dx x 1
BC = pz x ds x 1
Weight of element = (mass of element) x g
C
= (volume x r)x g
Revolving the force in x-direction, we have
px x dy x 1 – p(ds x 1)sin (90o – q) =0
px x dy x 1 –pz x ds x 1 cos q =0
From fig. ds cos q = AB = dy
So
px x dy x 1 - pz x ds x dy = 0
px = pz
Hydrostatic Law
• The pressure at any point in a fluid at rest is obtained by the
Hydrostatics Law.
• The rate of increase of pressure in vertically downward direction
must be equal to the specific weight of the fluid at that point.
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Bina Nusantara
Application
•
•
•
•
Communicating Tube
Pascal’s Paradox
Hydraulic Jack
Manometer
- U-Tube Manometer
- Prandtl-Manometer
- Betz-Manometer
- Manometer for Small Pressure Difference
• Hydraulic Siphon
• Chimney
Bina Nusantara
Application
Hydraulic Jack
(3.6)
▲ Fig. 3.9
Bina Nusantara
Manometer
A) U-Tube Manometer
(3.7)
(3.8)
(3.9)
◀ Fig. 3.10
Bina Nusantara
B) Prandtl-Manometer
(3.10)
(3.11)
◀ Fig. 3.11
Bina Nusantara
C) Betz-Manometer
▲ Fig. 3.12
Bina Nusantara
D) Manometer for Small Pressure Difference
(3.12)
(3.13)
(3.14)
(3.15)
▲ Fig. 3.13
Bina Nusantara
Hydraulic Siphon
(3.16)
▲ Fig. 3.14
Bina Nusantara
Chimney
▲ Fig. 3.15
Bina Nusantara