Hydrostatic Force acting on Submerged Surface
The thrust force acting on a surface submerged in a liquid can be calculated as
F = p a A
= ρ g h a A (1)
where
F = thrust force (N)
p a = ρ g h a = average pressure on the surface (Pa)
A = area of submerged surface (m 2 )
h a = average depth (m)
ρ = density (kg/m 3 ) (water 1000 kg/m 3 )
g = acceleration of gravity (9.81 m/s 2 )
Example - The thrust force acting on the side of a container
The trust force acting on the submerged vertical side of a container can be calculated as
F = p a A
= ( (p t + p b ) / 2) A
= ( ρ g (h t + h b ) / 2) A (2)
where
p t = pressure at the top of the submerged surface (Pa)
p b = pressure at the bottom of the submerged surface (Pa)
h t = depth at the top of the submerged surface (m)
h b = depth at the bottom of the submerged surface (m)
The thrust on a surface with width 1 m and height from 0 m to 2 m - in a water-filled container can be calculated as
F = ( ρ g (h t + h b ) / 2) A
= (1000 kg/m 3 ) (9.81 m/s 2 ) ((0 m) + (2 m)) / 2) ( (1 m) (2 m) )
= 19620 N
= 19.6 kN
Example - The thrust force acting on the bottom of a container
The trust force acting on the horizontal bottom of a submerged container can be calculated as
F = p b A
= ρ g h b A (2b)
The thrust on a bottom with width 1 m and length 2 m - on depth 1 m - in a water filled container can be calculated as
F = ρ g h b A
= (1000 kg/m 3 ) (9.81 m/s 2 ) (1 m) ( (1 m) (2 m))
= 19620 N
= 19.6 kN
Related Topics
• Fluid Mechanics
The study of fluids - liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.
Related Documents
Archimedes' Law
Forces acting on bodies submerged in fluids.
Buoyancy
Buoyancy is the resultant force acting on a submerged body.
Center of Gravity
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Center of Gravity and Buoyancy
Stability - the center of gravity vs. the center of buoyancy.
Hydrostatic Pressure vs. Depth
Depth and hydrostatic pressure.
Underground Pipes - Earth Pressure
Pressure acting on underground pipes due to weight of soil and transport.