Fluid Mechanics


Skin Friction Coefficient

 , where:

C= Skin Friction Coefficient

 = Wall Shear Stress (Pa)

 = Fluid Density (kg/m^3)

U = Free Stream Velocity (m/s)

Speed of Sound

 , where:

a = Speed of Sound (m/s)

 = Heat Capacity Ratio, approximately:

  • 1.4 for Oxygen (Natural Gas)
  • 1.7 for Argon
  • 1.4 for Hydrogen
  • 1.3 for Water (Steam)

p = Pressure (Pa)

Stagnation Temperature

 , where:

T= Stagnation (or total) temperature (K)

T = Static Temperature (K)

pt = Stagnation (or total) pressure (Pa)

p = Static Pressure (Pa)

 = Heat Capacity Ratio, approximately:

Stokes Terminal Velocity

 , for spherical particles falling in liquids with low Reynolds Number.

vs = Terminal or settling velocity (m/s)

 = Density of falling particle (kg/m^3)

 = Density of fluid (kg/m^3)

Stokes' Law

 applies to spherical objects with small Reynolds numbers where:

Fd = Drag Force (N)

 = Dynamic Viscosity (Pa*s)

R = Radius (m)

vs = Velocity (m/s)