The Coriolis effect causes objects, which should move in a straight line, to deviate from their course. This is an essential phenomenon that affects, for example, the movement of airplanes and missiles. You can use our Coriolis effect calculator if you want to compute the strength of the Coriolis force acting on an object. Keep reading and find answers to the questions: What is the Coriolis effect? What is the Coriolis effect definition? How does Coriolis effect influence airplanes?
What is the Coriolis effect?
Coriolis effect is caused by the inertial force resulting from the rotational movement of the Earth, which rotates around its own axis from the west to the east. As a result, every moving object will be subject to this rotation and thus change the direction of its movement:
- in the northern hemisphere, the direction of a moving body deflects to the right,
- in the southern hemisphere, the direction of a moving body deflects to the left.
Coriolis effect definition
Coriolis force can be easily estimated with the Coriolis effect definition below:
F = 2 * m * v * ω * sin(α)
Fis the Coriolis force,
mis the mass of the moving object,
vis the velocity of the moving object,
ωis the angular velocity of the Earth,
αis the latitude at which the object is located.
Associated Coriolis acceleration equals:
a = F / m = 2 * v * ω * sin(α)
In our Coriolis effect calculator, the rotating body is assumed to be Earth with angular velocity
ω = 2π/24h ≈ 0.0000727 1/s (
360° in radians). If you want to change it, you can go to the advanced mode.
You can see from above equation that the magnitude of Coriolis force depends on the latitude at which the object is located. The Coriolis effect is greater near the poles where
α = 90° (
sin(90°) = 1) and decreases to zero at the equator
α = 0° (
sin(0°) = 0).
Coriolis effect and airplanes
Do Coriolis effect and airplanes have something in common? Of course they have! Let's say that an airplane (
m = 50,000 kg) takes off from London (
α = 51.50° N) and travels to North America (to the west) with the velocity
v = 500 km/h. With our Coriolis effect calculator we can compute that this airplane is subjected to the Coriolis force
F ≈ 800 N which means that it deflects to the north with the acceleration
a = F / m = 0.016 m/s². It is almost 0.2% of the Earth's gravity! Pilots need to establish a constant force sideways, equal but opposite to the coriolis force, to compensate it. It is achieved automatically, by the autopilot, by slightly banking the airplane to keep the heading as planned.
For this example, the banking angle equals only about
atan(0.002*g/g) ≈ 0.115°, so it is too small to be perceivable by passengers. However, without this correction, the airplane may land hundreds or thousands of miles away from the destination point. It is even a possibility that it would fly around the circle, never reaching a final airport!