Coriolis Acceleration

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

(mechanics)

An acceleration which, when added to the acceleration of an object relative to a rotating coordinate system and to its centripetal acceleration, gives the acceleration of the object relative to a fixed coordinate system.

A vector which is equal in magnitude and opposite in direction to that of the first definition.

---

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

Figure 1

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_transν_relsin 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