Velocity Head

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Dynamic pressure in a fluid flow can be expressed as

p_d = ρ_f v² / 2   (1)

where 

p_d = dynamic pressure in fluid (Pa, psi)

ρ_f = density of fluid (kg/m³, lb/ft³)

v = fluid velocity (m/s, ft/s)

Head water column can be calculated by dividing dynamic pressure with specific weight of water like 

h_w = p_d / γ_w 

  =  (ρ_f v²/2) /  ρ_w g  

  = ρ_f v²/ 2 g    (2)

where

h_w = head water (m Water, ft Water)

γ_w  = ρ_w g = specific weight water

where 

 ρ_w = density of water (kg/m³, lb/ft³)

g = acceleration of gravity (32.174 ft/s², 9.81 m/s²)

Air Flow - Velocity and Dynamic Head Chart 

Charts based on air density 1.205 kg/m³ and water density 1000 kg/m³.

• Air Flow - Velocity and Dynamic Head Chart (pdf)

Water Flow - Velocity and Dynamic Head Chart

• Water Flow - Velocity and Dynamic Head Chart (pdf)

Heads at different velocities are indicated in the table below:

• 1 ft (foot) = 0.3048 m = 12 inches = 0.3333 yd

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Related Topics

• Fluid Mechanics - The study of fluids - liquids and gases. Involves various properties of the fluid, such as velocity, pressure, density and temperature, as functions of space and time.

Related Documents

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