What is the direction of the wind based on flag direction

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Discussion Overview

The discussion centers around the relationship between the direction of wind and the orientation of flags, particularly in the context of sailing ships and wind cones. Participants explore various scenarios and interpretations of how flags behave in different wind conditions, including practical experiments and artistic representations.

Discussion Character

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

Main Points Raised

  • Some participants suggest that the wind direction indicated by a flag is approximately 90 degrees off from the wind's origin, particularly in open fields.
  • Others question whether a flag behaves differently than a wind cone, prompting discussions about the accuracy of wind direction representation.
  • A participant proposes that the flag should point directly opposite to the wind direction (180 degrees), claiming this is confirmed in practice.
  • There are references to sailing ships and how they may not always be oriented directly downwind, with some arguing that they can sail into the wind through a technique called tacking.
  • Participants express uncertainty about the depiction of sails in paintings, noting that the sails may not align with the wind direction indicated by the flag.
  • Some participants humorously speculate about the accuracy of artistic representations and the potential influence of the painter's state of mind on the depiction of wind and sails.
  • There is a discussion about the apparent wind experienced on a sailboat, suggesting that the flag's orientation may differ due to airflow affected by the sails.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the relationship between flag direction and wind direction, with multiple competing views and interpretations remaining throughout the discussion.

Contextual Notes

Some assumptions about the behavior of flags and sails in different wind conditions are not fully explored, and there are unresolved questions regarding the accuracy of artistic representations of sailing scenarios.

TheWonderer1
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I think it is about 90 degrees off but I never thought about wind direction too much. I guess let's say the wind is coming from the NE and there is nothing behind the flag so it's on a field. I know a windcone is 180 degrees so opposite wind direction.
 
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Why do you think a flag would be any different froma windcone? And if it was not 180 degrees off, which of the two directions would it go?
 
TheWonderer1 said:
I think it is about 90 degrees off...

How about directly upwind, like on many sail ship paintings?

ba88118a36c5459f9fd0b485d662fc39.jpg
 
Getting a small flag and blowing on it is also a fairly simple experiment, if you've any doubts.
 
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I figured out soon after writing it. It should be 180 degrees and found that this is true in practice.
 
A.T. said:
How about directly upwind, like on many sail ship paintings?

To be fair, sailing ships aren't necessarily pointed directly downwind ( and in fact perform better when they aren't. They can even almost sail into the wind, called tacking. So the picture isn't really impossible by any stretch.
 
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boneh3ad said:
To be fair, sailing ships aren't necessarily pointed directly downwind ( and in fact perform better when they aren't. They can even almost sail into the wind, called tacking. So the picture isn't really impossible by any stretch.
That picture is. Note the sails.
 
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A.T. said:
That picture is. Note the sails.

filling in different directions LOL
 
  • #10
davenn said:
filling in different directions LOL
There could be a strong velocity gradient ... :biggrin:
 
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  • #11
A.T. said:
Note the sails.

I wonder if they are using the same wind we are using.
 
  • #13
Also, I must say that it is not completely clear to me that the flag is flying towards the stern and the sails could very well be at an angle to the ship that is not 90 degrees. Compare to this:
3361341497_78bcf03ea4_b.jpg
 
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  • #14
Orodruin said:
Also, I must say that it is not completely clear to me that the flag is flying towards the stern and the sails could very well be at an angle to the ship that is not 90 degrees. Compare to this:
View attachment 203255

That's a different type of sails. What you mean would look like this on the pirate ship above:

can-stock-photo_csp3961721.jpg


But this is not how that sails are set on the pirate ship image (which was just an example for an error you sometimes see, maybe not the clearest one).
 
  • #15
Eh, is the suggestion here that on a sail boat it would be different? Went away for a while but in fact, that's why I asked.
 
  • #16
TheWonderer1 said:
Eh, is the suggestion here that on a sail boat it would be different? Went away for a while but in fact, that's why I asked.
On a sail boat the flag orients down the apparent wind. At the height of the sails (like the big US one above) it's affected by the airflow diverted by the sails.
 

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