Elementary Mechanics of Fluids

1. Elementary Mechanics of Fluids CE 319 F Daene McKinney Hydrostatic Forces on Plane Surfaces

2. F Centroid Center of pressure Pressure on Plane Surface Surfaces exposed to fluids experience a force due to the pressure distribution in the fluid

3. Plywood Form (2.44m x 1.22m) Concrete (23.6 kN/m3) 2.44 m F Example

4. F Centroid Center of pressure Line of Action of Force • Lies below centroid, since pressure increases with depth

5. T F Example (3.59) • F  as H ? •  as H ? • is constant as H ? • T  as H ? • T is constant as H ?

7. 0.133 Fw,g 2 Fb,g Example (3.73) Find: Force of block on gate F

8. RA 6 3-0.4641 F Example (3.78)

9. HW (3.87)

10. HW (3.92)

11. Air G 5.01 ft 18 ft Water A Oil SG=0.75 gate 6 ft B Example Given: Gate AB is 4 ft wide, hinged at A. Gage G reads -2.17 psi Find: Horizontal force at B to hold gate. Solution: Convert negative pressure in tank to ft of water

12. A Air G 5.01 ft 3.03 ft 4ft 18 ft Fw Water Foil A FB Oil SG=0.75 gate 6 ft B B Example

13. HW (3.96)

14. HW (3.102)