# Coriolis acceleration

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## Coriolis acceleration

[kȯr·ē′ō·ləs ik‚sel·ə′rā·shən]## Coriolis Acceleration

[named after the French scientist G. Coriolis], a rotational acceleration, a part of the total acceleration of a point that appears in the so-called composite motion, when the transferred motion, that is, the motion of a moving frame of reference, is not translational. Coriolis acceleration

appears as a consequence of a change in the relative velocity of a point ν_{rel} in the transferred motion (motion of the moving frame of reference) and of the transferred velocity in the relative motion. Numerically, the Coriolis acceleration is

w_{Cor} = 2ω_{trans}ν_{rel}sin α

where ω_{trans} is the angular velocity of rotation of the moving frame of reference about some axis *AB* and a is the angle between ν_{rel} and the axis *AB*. As a vector, the Coriolis acceleration is given by

The direction of the Coriolis acceleration can be obtained by projecting the vector ν_{rel} on a plane perpendicular to the *AB* axis and rotating this projection by 90° in the direction of the transferred motion (see Figure 1, in which the velocity of the point *M* along the meridian *AMB* of a sphere is ν_{rel}, while the rotational velocity of the sphere about the *AB* axis is ω).

It should be emphasized that the Coriolis acceleration is the part of the acceleration of the point relative to the fixed frame of reference and not to the moving frame of reference. For example, for motion along the surface of the earth, owing to the earth’s rotation a point will have a Coriolis acceleration with respect to the stars, not to the earth. The Coriolis acceleration is equal to zero when the motion of the moving frame of reference is purely translational (oω_{trans} = 0) or when α = 0.

The concept of Coriolis acceleration is used in solving various problems in kinematics and dynamics (*see*).

S. M. TARG