Dynamic Pressure
Dynamic pressure is the kinetic energy per unit volume of a fluid in movement.
Dynamic pressure is the kinetic energy of a flowing fluid  liquid or gas  per unit volume  and can be expressed as
p _{ d } = 1/2 ρ v^{2}(1)
where
p _{ d } = dynamic pressure (N/m^{2}(Pa), lb_{f} /ft^{2}(psf))
ρ = density of fluid (kg/m^{3}, slugs /ft^{3} )
v = velocity (m/s, ft/s)
Dynamic Pressure Calculator  SI Units
The default values below are for water with density of 1000 kg/m^{3} .
 1 N/m^{2}= 1 Pa = 1.4504x10^{4} lb_{f} /in^{2}(psi) = 0.02089 lb_{f} /ft^{2}(psf) = 1x10 ^{ 5 } bar = 4.03x10^{3} in water = 0.336x10^{3} ft water = 0.1024 mm water = 0.295x10^{3} in mercury = 7.55x10^{3} mm mercury = 0.1024 kp/m^{2}= 0.993x10 ^{ 5 } atm
Dynamic Pressure Calculator  Imperial Units
The default values below are for water with density of 1.940 slugs .
Some common densities at atmospheric pressure:
 Water  0 ^{o}C  1000 kg/m^{3}
 Water  32 ^{o}F  1.940 slugs/ft^{3}
 Air  20 ^{o}C  1.2 kg/m^{3}
 Air  60 ^{o}F  2.373 10^{3} slugs/ft^{3}
Example  The Dynamic Pressure in a Water Flow
The dynamic pressure in water with  temperature 20 ^{o}C  density 1000 kg/m^{3} and velocity 5 m/s  can be calculated as
p _{ d } = 1/2 (1000 kg/m^{3} ) (5 m/s)^{2}
= 12500 Pa
= 12.5 kPa
Example  Hurricane and Force acting on a Wall
The dynamic pressure in a hurricane with air temperature 20 ^{o}C, density of air 1.2 kg/m^{3} and wind speed 37 m/s can be calculated as
p _{ d } = 1/2 (1.2 kg/m^{3} ) (37 m/s)^{2}
= 821 Pa (N/m^{2})
The force acting directly on a wall with area 10 m^{2} can be calculated as
F = p _{ d } A
= (821 N/m^{2}) (10 m^{2})
= 8210 N
= 8.2 kN
 almost the weight of a small car.
Note!  the real force acting on the wall  or an other obstruction in the wind  is in general more complicated to calculate due to drag , turbulence and other effects.
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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