_Coriolis Effect
I will not be going into unnecessary facts, so that it’ll be easy to you to understand. Anyway I try to give you the essence of it
“Deflection of moving objects when they are viewed in a rotating reference frame”
- Acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame
- And proportional to the object's speed (or rotation rate) in the rotating frame.
ii. The centrifugal force
- Acts outwards in the radial direction
- And proportional to the distance of the body from the axis of the rotating frame.
“Deflection of moving objects when they are viewed in a rotating reference frame”
- Simply it is, in a reference frame with clockwise rotation, the deflection is to the left of the motion of the object whereas in one with anti-clockwise rotation, the deflection is to the right.
- The Coriolis Effect is caused by the rotation of the Earth and the inertia of the mass which we consider.
- Newton's laws of motion apply to an object in an inertial (non-accelerating or simply inactive) frame of reference.
- When Newton's laws are transformed to a rotating frame of reference, the Coriolis and centrifugal (force acts outwards of the center of rotation or axis) forces appear (those both forces are proportional to the mass of the object).
- Acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame
- And proportional to the object's speed (or rotation rate) in the rotating frame.
ii. The centrifugal force
- Acts outwards in the radial direction
- And proportional to the distance of the body from the axis of the rotating frame.
- These forces are termed either inertial forces, fictitious forces or pseudo forces. They allow the application of simple Newtonian laws to a rotating system. They do not exist in a true non-accelerating "inertial" system.
- As we know the most commonly used rotating reference frame is the Earth.
- Because the Earth completes only one rotation per day, the Coriolis force is quite small
- To become its effects noticeable, it should be a motion which occurs over a large distance and long period of time, such as large-scale movement of air in the atmosphere (something like a tornado) or water in the ocean (something like a whirlpool). Such motions are limited by the 2-dimensional surface of the earth, so only the horizontal component (i.e. how far above or below the equator. Maximum horizontal effect is at the poles, zero at the equator) of the Coriolis force is generally important.
- Now comes the interesting part
- This force causes moving objects on the surface of the Earth to appear to swerve (go around) to the right in the northern hemisphere, and to the left in the southern instead flowing directly from areas of high pressure to low pressure, as they would on a reference frame at rest (non-rotating)
- Winds and currents tend to flow to the right of this direction north of the equator, and to the left of this direction south of it. This effect is responsible for the rotation of large cyclones.
In the inertial frame of reference (upper part of the picture), the black object moves in a straight line (assume there is no significant friction). The observer (red dot) who is standing in the rotating (non-inertial) frame of reference (lower part of the picture) sees the object as following a curved path due to the Coriolis and centrifugal forces present in this frame.
At last, that makes it. I hope that you understood it. |