Hydrostatic Force acting on Submerged Surface
Calculate the thrust force acting on a 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 waterfilled 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.
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