Useful equations and conversions – Xylem 407119A HOT WIRE ANEMOMETERS User Manual
Page 11
Model 407119A Version 4.1 October 2005
11
Useful Equations and Conversions
Area equation for rectangular or square ducts
Area equation for circular ducts
Cubic equations
NOTE:
Measurements made in inches
must be converted to feet or meters before using the above formulae.
Unit of Measure Conversion Table
m/s
ft/min
knots
km/h
MPH
1 m/s
1
196.87
1.944
3.6
2.24
1 ft/min
0.00508
1
0.00987
0.01829
0.01138
1 knot
0.5144
101.27
1
1.8519
1.1523
1 km/h
0.2778
54.69
0.54
1
0.6222
1 MPH
0.4464
87.89
0.8679
1.6071
1
Width (W)
Height (H)
Area (A) = Width (W) x Height (H)
CFM (ft
3
/min) = Air Velocity (ft/min) x Area (ft
2
)
CMM (m
3
/min) = Air Velocity (m/sec) x Area (m
2
) x 60
Radius
Area (A) =
x r
2
Where
= 3.14 and r
2
= radius x radius