Velocity Head

Dynamic pressure and velocity head

Dynamic pressure in a fluid flow can be expressed as

pd = ρf v/ 2   (1)

where 

pd = dynamic pressure in fluid (Pa, psi)

ρf = 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 

hw = pγw 

  = f v2/2) /  ρw g  

  = ρf v2/ 2 g    (2)

where

hw = head water (m Water, ft Water)

γw  = ρw g = specific weight water

where 

 ρw = 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 Head

Water Flow - Velocity and Dynamic Head Chart

Air Flow - Velocity and Head

 

Velocity Heads

Velocity
- v -
(ft/sec)
Velocity Head
- v2/2g -
(ft Water)
0.5 0.004
1.0 0.016
1.5 0035
2.0 0.062
2.5 0.097
3.0 0.140
3.5 0.190
4.0 0.248
4.5 0.314
5.0 0.389
5.5 0.470
6.0 0.560
6.5 0.657
7.0 0.762
7.5 0.875
8.0 0.995
8.5 1.123
9.0 1.259
9.5 1.403
10.0 1.555
11.0 1.881
12.0 2.239
13.0 2.627
14.0 3.047
15.0 3.498
16.0 3.980
17.0 4.493
18.0 5.037
19.0 5.613
20.0 6.219
21.0 6.856
22.0 7.525
  • 1 ft (foot) = 0.3048 m = 12 inches = 0.3333 yd

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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