Coefficient of friction

Mechanics of the fluids

Aerodynamic, Hydrodynamic

In the calculation of a Trailed or Resistance of friction RF, the coefficient of friction noted cf applies to a surface of reference S.

RF = Q. S. cf

with Q: dynamic Pressure

Values of the cf

in water

  • Turbulent flow. General formulation ITTC (International Towing Tank Conference):
cf = 0.075. (log Re -2) ²
with log Re: decimal logarithm of the Reynolds number = V. L/naked
with V: speed in m/s, L: reference length of the body (length of floating, Cord of a profile), naked: kinematic viscosity = xxx (water with 15°C)
  • correction for roughness
delta cf is added to the cf

in the air

to follow

Random links:-289 | 1977 | Faye Dunaway | French industry of the shoe | Joseph-Moynat stage | The Family spirit | Liste_de_destinataires_de_croix_de_Crète_Victoria