1. BIEN 301 Individual Project Presentation Hydrostatic Force Against A Dam
Scott C. Laura

2. Hydrostatic Force:
The pressure force related to the weight of a fluid bearing on a surface
No motion in the fluid
Sum of forces = zero

3. Need to Know Values

4. Horizontal Component, Fh
The horizontal component of force on a curved surface equals the force on the plane area formed by the projection of the curved surface onto a vertical plane normal to the component.
The force in the x direction can be thought of as a resistance to shear stress Δx

5. Fh has a line of action below the centroid (0,0) onto the point ycp
Actually Z

6. Z
Add Mag
of Ycp
To ½ Z
Below
The
Surface = X Y

7. Vertical Component, Fv
The vertical component of force on a curved surface equals the weight of the effective column of fluid necessary to cause the pressure on the surface.
Force at any point
is equal to the sum
of all the above
weights Δz
+ Patm

8. The force acts downward through the centroid

9. Problem # 2.82
Determine the horizontal and vertical components of the hydrostatic force against the dam and the point (CP) where the resultant strikes the dam.
Fig. P2.82
Water
20 m CP
Pa = 0
50 m

10. Assumptions: Hydrostatic – water is not moving Uniform Density
Incompressible
20 degrees

11. Given: H = 20 meters L = 20 meters W = 50 meters pa = 0
Quarter Circle in shape
Water
Dam

12. Approach: Hydrostatic Forces On Curved Surfaces Calculate Fh
Calculate Ycp
Calculate Fv
Calculate the x value of the centroid
Find the resultant force

17. Resultant:
Tan-1(153.8/97.9) = 57.5°

18. ө

19. BME Application
Hydrostatic force is a vital concept in estimating our body’s conditions
From headaches to keeping us alive through diffusion and osmosis
Our body can even sense when we need to urinate by the pressure within the bladder