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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