Measures of Rotation Rate of the Table

The rotation rate of our table can be quoted in various units. The following are often used – period, revolutions per minute, or units of ‘f’, as described below.

  1. The angular velocity of the tank, Ω , in radians per second
  2. The Coriolis parameter (f) defined as f = 2Ω
  3. The period of one revolution of the tank, τ, in seconds is τ = 2π/Ω
  4. Revolutions per minute, rpm = 60/τ

Conversion table

Ω (rad/s) 0 0.25 0.5 1 1.5 2
f=2Ω(rad/s) 0 0.5 1 2 3 4
τ(s) 8π = 25. 1 4π = 12. 6 2π = 6. 3 4π/3 = 4. 2 π = 3.14
rpm 0 2. 4 4. 7 9.5 14.3 19.1

Note that on the ‘big’ table pictured above, the digital readout is the rotation rate in `milli-f’: thus 1000 is a rotation rate of 1x f: the period of rotation is thus 12.6 s.