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I have rewritten to remove ambiguity and to clarify the physics of the situation
Tayana 20:44, 19 September 2006 (UTC)
Tayana 23:02, 20 September 2006 (UTC)
There is a an article Points of sail. It should not be necessary to duplicate information between apparent wind and points of sail. Duplication will make for incconsistency between articles as contributors to points of sail may not be well versed with the physics as those who may address apparent wind and error will occur and make updating difficult. Wikipedia must not become like a Tower of Babel
Tayana 21:28, 21 September 2006 (UTC)
Your sentence ("In sailing, and especially in sailboat racing, apparent wind is a vitally important factor, when determining the Points of sail a sailboat can successfully travel in") is OK and feel free to edit accordingly.
Tayana 21:17, 22 September 2006 (UTC)
IMO what is lacking is a clear definition of the marine term. The definition is valid, although focussed on the observer. Also, I would like to incude mathematical references to the vector calculation of apparent wind speed and angle.
My suggestion: Apparent Wind is the air flow relative to a moving object. Apparent Wind in marine terminology is the flow of air acting upon a sail, or the wind as it appears to the sailor. It differs from the true absolute wind observed by a stationary observer in velocity and direction.
Feuser 22:28, 4 June 2007 (UTC)
01:00, 11 June 2007 (UTC)
http://simple.wikipedia.org/wiki/Reciprocal
http://www.mathsteacher.com.au/year7/ch04_frac/06_recip/num.htm
a = 90
W = 18
H = 25
A = sqrt((25+18*cos(90))^2 + (18*sin(90))^2)
A = sqrt((25+0)^2 + (18*1)^2)
A = sqrt (625 + 324)
A = 30.80
W = 10
H = 10
a = 90
b = angle of apparent wind
A = velocity of apparent wind = sqrt((H+W*cos(a))^2 + (W*sin(a))^2) AcosD = inverse cosine in degrees
b = AcosD((H+(W×COS(a)))/A)
b = AcosD ((10+(10/14.14213562373)
b = AcosD 1.41421356237
b = 45
Angle and velocity of apparent wind in going 35 in 30 knots on a broad reach (115 deg)
W = 30
H = 35
a = 115
b = angle of apparent wind in degrees
A = velocity of apparent wind
b = AcosD((H+(W*cos(a))/sqrt((H+W*cos(a))^2 + (W*sin(a))^2))
A = sqrt ((30+35*-0.42261826174)^2+(30*0.90630778704)^2)
b = 47.14
A = 35.17
I believe using the variable H (head wind) summarizes more clearly the actual effect of boat speed (velocity) over ground. My apologies if my re-write deleted parts of your article - I feel your contributions were valuable and I believe the reference to classical mechanics was correct. However the term relative in the core definition would be misleading as it is used in the contrext of general relativity in the linked article.
Feuser 03:28, 13 June 2007 (UTC)
Hey 194.46.241.162
I think the latest addition is not only confusing but also a regression:
"This is the Inverse (mathematics) of the objects actual velocity or more succinctly the apparent wind is defined as the Velocity of the wind minus the Velocity of the object."
We've already established that "Apparent wind is the vector sum of the True Wind Velocity and the air stream generated by an "object's Velocity over ground".
The air stream generated by the objects' "Velocity over ground" is, in fact, the sum of the inverse velocity of the object and any current or displacement of the base medium. Therefore the effect of the objects motion relative to the wind is summarized as "head wind" (H).
Edit by Joern [83.21.158.93]: I have to state as a sailor, that the formulas are wrong. the Objects velocity must not be subtracted from the cosine term but rather beeing added to it. —Preceding unsigned comment added by 83.21.158.93 ( talk) 08:08, 28 April 2009 (UTC)
Edit Feuser: Take a boat going dead downwind at 8 knots in 10 knots true. Your apparent wind will be 2 knots. I also removed redundant language from the Definition section. The movement of the vessel does not need to be described in order to convey the fact that the apparent wind is different from the true wind acting upon a stationary object. The following paragraph serves to explain the physics.
Wikipedia Terminology Conflict: "Headwind"
In this article, headwind is defined as the component of apparent wind that's due to an object's velocity, and is a vector that adds to true wind. Compare this to the Wikipedia article on Tailwind (there's no Headwind article), which states "A tailwind is a wind that blows in the direction of travel of an object, while a headwind blows against the direction of travel." In other words, a headwind doesn't add to true wind, it is true wind.
This is a direct contradiction that needs to be resolved. I suspect that the aeronautics-oriented tailwind article is correct while this article needs to adopt a better term.
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
|
I have rewritten to remove ambiguity and to clarify the physics of the situation
Tayana 20:44, 19 September 2006 (UTC)
Tayana 23:02, 20 September 2006 (UTC)
There is a an article Points of sail. It should not be necessary to duplicate information between apparent wind and points of sail. Duplication will make for incconsistency between articles as contributors to points of sail may not be well versed with the physics as those who may address apparent wind and error will occur and make updating difficult. Wikipedia must not become like a Tower of Babel
Tayana 21:28, 21 September 2006 (UTC)
Your sentence ("In sailing, and especially in sailboat racing, apparent wind is a vitally important factor, when determining the Points of sail a sailboat can successfully travel in") is OK and feel free to edit accordingly.
Tayana 21:17, 22 September 2006 (UTC)
IMO what is lacking is a clear definition of the marine term. The definition is valid, although focussed on the observer. Also, I would like to incude mathematical references to the vector calculation of apparent wind speed and angle.
My suggestion: Apparent Wind is the air flow relative to a moving object. Apparent Wind in marine terminology is the flow of air acting upon a sail, or the wind as it appears to the sailor. It differs from the true absolute wind observed by a stationary observer in velocity and direction.
Feuser 22:28, 4 June 2007 (UTC)
01:00, 11 June 2007 (UTC)
http://simple.wikipedia.org/wiki/Reciprocal
http://www.mathsteacher.com.au/year7/ch04_frac/06_recip/num.htm
a = 90
W = 18
H = 25
A = sqrt((25+18*cos(90))^2 + (18*sin(90))^2)
A = sqrt((25+0)^2 + (18*1)^2)
A = sqrt (625 + 324)
A = 30.80
W = 10
H = 10
a = 90
b = angle of apparent wind
A = velocity of apparent wind = sqrt((H+W*cos(a))^2 + (W*sin(a))^2) AcosD = inverse cosine in degrees
b = AcosD((H+(W×COS(a)))/A)
b = AcosD ((10+(10/14.14213562373)
b = AcosD 1.41421356237
b = 45
Angle and velocity of apparent wind in going 35 in 30 knots on a broad reach (115 deg)
W = 30
H = 35
a = 115
b = angle of apparent wind in degrees
A = velocity of apparent wind
b = AcosD((H+(W*cos(a))/sqrt((H+W*cos(a))^2 + (W*sin(a))^2))
A = sqrt ((30+35*-0.42261826174)^2+(30*0.90630778704)^2)
b = 47.14
A = 35.17
I believe using the variable H (head wind) summarizes more clearly the actual effect of boat speed (velocity) over ground. My apologies if my re-write deleted parts of your article - I feel your contributions were valuable and I believe the reference to classical mechanics was correct. However the term relative in the core definition would be misleading as it is used in the contrext of general relativity in the linked article.
Feuser 03:28, 13 June 2007 (UTC)
Hey 194.46.241.162
I think the latest addition is not only confusing but also a regression:
"This is the Inverse (mathematics) of the objects actual velocity or more succinctly the apparent wind is defined as the Velocity of the wind minus the Velocity of the object."
We've already established that "Apparent wind is the vector sum of the True Wind Velocity and the air stream generated by an "object's Velocity over ground".
The air stream generated by the objects' "Velocity over ground" is, in fact, the sum of the inverse velocity of the object and any current or displacement of the base medium. Therefore the effect of the objects motion relative to the wind is summarized as "head wind" (H).
Edit by Joern [83.21.158.93]: I have to state as a sailor, that the formulas are wrong. the Objects velocity must not be subtracted from the cosine term but rather beeing added to it. —Preceding unsigned comment added by 83.21.158.93 ( talk) 08:08, 28 April 2009 (UTC)
Edit Feuser: Take a boat going dead downwind at 8 knots in 10 knots true. Your apparent wind will be 2 knots. I also removed redundant language from the Definition section. The movement of the vessel does not need to be described in order to convey the fact that the apparent wind is different from the true wind acting upon a stationary object. The following paragraph serves to explain the physics.
Wikipedia Terminology Conflict: "Headwind"
In this article, headwind is defined as the component of apparent wind that's due to an object's velocity, and is a vector that adds to true wind. Compare this to the Wikipedia article on Tailwind (there's no Headwind article), which states "A tailwind is a wind that blows in the direction of travel of an object, while a headwind blows against the direction of travel." In other words, a headwind doesn't add to true wind, it is true wind.
This is a direct contradiction that needs to be resolved. I suspect that the aeronautics-oriented tailwind article is correct while this article needs to adopt a better term.