Does the Coriolis Effect Determine the Direction of Curl in Hemispheres?

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Discussion Overview

The discussion revolves around the Coriolis effect and its relationship to the direction of curl in different hemispheres, specifically in the context of meteorological phenomena such as cyclones. Participants explore the implications of the Coriolis effect on motion and clarify terminology related to curl.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions whether the Coriolis effect dictates that curl is always negative in the northern hemisphere and positive in the southern hemisphere.
  • Another participant explains that the Coriolis effect is related to the vector cross product of Earth's rotation and velocity, suggesting that the sign of curl cannot be generalized by hemisphere.
  • A participant notes that in the northern hemisphere, a bullet's trajectory is deflected clockwise, while in the southern hemisphere, it is deflected counter-clockwise, indicating a difference in behavior due to the Coriolis effect.
  • There is a clarification on the term "curl," with participants discussing whether it refers to the mathematical operator ∇× or something else.
  • One participant admits to confusion regarding the terminology and acknowledges a misunderstanding related to the concept of curl.

Areas of Agreement / Disagreement

Participants express differing views on whether the Coriolis effect can be generalized to determine the sign of curl based on hemisphere. The discussion remains unresolved regarding the implications of the Coriolis effect on curl and the correct terminology.

Contextual Notes

There is a lack of clarity regarding the definitions and assumptions related to the term "curl," which may affect the understanding of the Coriolis effect's implications. Additionally, the relationship between the Coriolis effect and the behavior of moving objects in different hemispheres is not fully settled.

Keru
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Two quick questions. Does the Coriolis effect mean that in the northern hemisphere the curl will always have a negative value and in the southern hemisphere a positive one? Is the curl in the eye of the cyclones equal to zero?
Thanks.
 
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The Coriolis effect is proportional to ##-2(\vec{\omega}\times\vec{v})## where ##\vec{\omega}## is pointing up out of the North pole, along the axis of Earth's rotation. Whether this curl is positive or negative depends on the vector ##\vec{v}## and can not be generalized to "northern vs southern hemisphere" effects. However, if something (say a bullet) is moving initially along a straight line in the Northern hemisphere, its trajectory will be deflected (by the Coriolis force) in a clockwise direction, while in the Southern hemisphere the trajectory would be deflected in a counter-clock-wise direction.
 
By "curl" do you mean \nabla\times or something else?
 
Haha! I had a brain fart and associated a cross product ##\vec{\omega}\times\vec{v}## as a curl. Now I'm not sure what the OP is asking.
 
Meir Achuz said:
By "curl" do you mean ∇×\nabla\times or something else?

Yes i meant ∇×. Sorry I am not english native speaker, searched for the translation and that's the best i had.
 

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