1. Pertemuan 03 - 04 Hydrostatics 1

2. Bina Nusantara 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. Focus : 1. Properties of Fluid 2. Pressure 3. Measurement of Pressure (Manometers) 4. Hydrostatics Flow  Vertical, Horizontal, Inclined, Curved 5. Bernoully 6. Buoyancy, stability of submerged and floating bodies

3. Bina Nusantara

9. 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)

10. 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

11. Bina Nusantara Pascal Law The pressure at a point in static fluid is equal in all direction Forces on a fluid element The forces acting on the element are : 1. Pressure forces formal to the surfaces 2. Weight of element in the vertical direction Forces on the face AB = p x x d y x 1 AC = p y x d x x 1 BC = p z x d s x 1 Weight of element = (mass of element) x g = (volume x  )x g Revolving the force in x-direction, we have p x x d y x 1 – p(ds x 1)sin (90 o –  =0 p x x d y x 1 –p z x d s x 1 cos  =0 From fig. ds cos  = AB = dy So p x x d y x 1 - p z x d s x dy = 0 p x = p z px.dy.1 pz.ds.1 py.dx.1   AC C

12. Bina Nusantara 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.

13. Bina Nusantara

25. Application Communicating Tube Pascal’s Paradox Hydraulic Jack Manometer - U-Tube Manometer - Prandtl-Manometer - Betz-Manometer - Manometer for Small Pressure Difference Hydraulic Siphon Chimney

26. Bina Nusantara Hydraulic Jack ▲ Fig. 3.9 (3.6) Application

27. Bina Nusantara Manometer A) U-Tube Manometer (3.7) (3.8) (3.9) ◀ Fig. 3.10

28. Bina Nusantara B) Prandtl-Manometer (3.10) (3.11) ◀ Fig. 3.11

29. Bina Nusantara C) Betz-Manometer ▲ Fig. 3.12

30. Bina Nusantara D) Manometer for Small Pressure Difference (3.13) (3.14) (3.15) (3.12) ▲ Fig. 3.13

31. Bina Nusantara Hydraulic Siphon (3.16) ▲ Fig. 3.14

32. Bina Nusantara Chimney ▲ Fig. 3.15