Formula Symbols and Units for Fluidics and Electric Engineering
Formula Symbol  Description  Unit  Note 



A  Surface, cross sectional area  m²  
a  Acceleration  m/s²  
c  Drag coefficient  
c_{p}  Specific isobar heat capacity  J/kg K  
c_{v}  Specific isochor heat capacity  J/kg K  
D, d  Diameter  m  
E  Energy  J  1 J = 1 N m = 1 W s = 1 VA s = 1 kg m²/s² 
F  Force  N  
f  Frequency  Hz  
f  Function of …, factor  
g  Gravitational acceleration  m/s²  Gravity ≅ 9.8 m/s² 
H  Height  m  
I  Pulse  Ns  1 Ns = 1 kg m/s 
İ  Pulsating current  N  1 N = kg m/s² 
i  Pulsating current density  Nm², Pa  1 Pa = N/m² = kg/s²m 
k  Roughness height  m  
k_{s}  Sand roughness height  m  
L  Length  m  
M  Mass  kg  
Ṁ  Mass flow  kg/s  
ṁ  Mass flow density  kg/s  
m  Opening ratio  
Mo  Momentum  
n  RPM  1/s  
n  Number  
n  Exponent  
P  Power  W  1 W = J/s = 1 Nm/s = 1 VA = 1 kg m²/s³ 
p  Pressure  N/m², Pa  1 Pa = 1 N/m² = 1 kg/s² m 
r  Radius  m  
r  Gas constant  J/kg K  
s  Thickness, wall thickness, length  m  
T  Temperature (Kelvin)  K  
t  Time  s  
U  Scale  m  
u  Speed Component  m/s  
V  Volume  m³  
V̇  Volumetric flow rate  m³/h  
v  Specific volume  m³/kg  v = V/M = 1/ρ 
v  Volumetric flow rate  m³/h  
v  Speed component  m/s  
W  Work  J  1 J = 1 Nm = 1 Ws = 1 VAs = 1 kg m²/s² 
w  Speed  m/s  
w_{T}  Friction velocity  m/s  
x  Coordinate for the direction of flow  
y  Coordinate transversely to the direction of flow  
α  Flow coefficient  
β  Angel  rad  
δ  Boundary layer thickness  m  
ζ  Coefficient of friction  
η  Viscosity  Pa s  1 Pa s = 1 Ns/m² = 1 kg/s m 
η  Efficiency  
ϑ  Temperature (Celsius)  ° C  °C = T273,15 K 
λ  Pipe friction factor  
μ  Contraction coefficient  
υ  Kinematic viscosity  m²/s  υ=η/ρ 
ρ  Density  kg/m³  υ=η/ρ 
τ  Shear stresses  N/m², Pa  1 Pa = 1 N/m² = 1 kg/s²m 
ψ  Cavity proportion 