In the design of fluid bearings, the Sommerfeld number (S), or bearing characteristic number, is a dimensionless quantity used extensively in hydrodynamic lubrication analysis. The Sommerfeld number is very important in lubrication analysis because it contains all the variables normally specified by the designer.
The Sommerfeld number is named after Arnold Sommerfeld (1868–1951).Related formulas
|S||Sommerfeld Number or bearing characteristic number (dimensionless)|
|r||shaft radius (m)|
|c||radial clearance (m)|
|μ||absolute viscosity of the lubricant (pascal*s)|
|N||speed of the rotating shaft (1/s)|
|P||load per unit of projected bearing area (N/m2)|