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Tension Discontinuity /DN
Moderator: Torsten
- Paul Arden
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Re: Tension Discontinuity /DN
Yes I think that the radius of the loop is very much tighter and the bottom of the loop begins and ends at the nose ie Tr should be there?
Cheers, Paul
Cheers, Paul
Re: Tension Discontinuity /DN
The path of a particle in the line is something like a cycloid, and so what?
Merlin
I guess this relates to alternative physics.It's a fallacy to think the size of the loop influences the aerodynamics of the loop.
Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
Charles Ritz, A Flyfisher's Life
Re: Tension Discontinuity /DN
Can you rephrase that? I don't understand what you mean by "the bottom of the loop begins and ends at the nose".Paul Arden wrote: ↑Sun Jun 20, 2021 3:01 pm Yes I think that the radius of the loop is very much tighter and the bottom of the loop begins and ends at the nose ie Tr should be there?
Cheers, Paul
FFi CCI
- Paul Arden
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Re: Tension Discontinuity /DN
Basically I was wondering if this would be a better representation…
Re: Tension Discontinuity /DN
The wording "tension discontinuty" is inappropriate and comes from a mathematical discontinuity found when solving equations for a string shooter. It is not appropriate to reality and I much prefer a "tension singularity" which does not violate the fact that a string is a continuous medium. I am writing a paper on that and shall have reading test with Paul before posting.
On the other hand negating front drag for a loop can be classified as alternative physics, and tension discontinuity as well.
Merlin
On the other hand negating front drag for a loop can be classified as alternative physics, and tension discontinuity as well.
Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
Charles Ritz, A Flyfisher's Life
Re: Tension Discontinuity /DN
For a single particle we can assume a combination of translation and rotation (like a rolling wheel) - that's why you're getting such a trajectory. A larger radius means that line more segments are exposed to form drag and thus have larger losses. So I'd still expect that this model produces plausible results, as long as the top and bottom legs are reasonable straight and the loop front is semicircular.
The alternative approach to solve this model with work/energy is here:
https://www.researchgate.net/publicatio ... g_dynamics
Gatti-Bono, Caroline & Perkins, N.. (2003). Comparison of numerical and analytical solutions for fly casting dynamics. Sports Engineering. 6. 165-175. 10.1007/BF02859893.
Daniel, you should get the same results, maybe you have compared them already.
The alternative approach to solve this model with work/energy is here:
https://www.researchgate.net/publicatio ... g_dynamics
Gatti-Bono, Caroline & Perkins, N.. (2003). Comparison of numerical and analytical solutions for fly casting dynamics. Sports Engineering. 6. 165-175. 10.1007/BF02859893.
Daniel, you should get the same results, maybe you have compared them already.
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Re: Tension Discontinuity /DN
Graeme,
Thanks for the great videos!
It amazes me how frequently something obvious slaps me in the face and shows me how off target my incorrect suspicions are... and all I can do is bang my forehead and say "Duh!"
I have always been fascinated by gyroscopes (there is a toy one on my desk as I type this). And I had the idea that the unrolling loop had some similar properties, or at least half of 'em. Your videos show that the particle doesn't even travel in half a circle... maybe 1/4 at most?
I have been daydreaming about this shit ever since!
Thanks for the great videos!
It amazes me how frequently something obvious slaps me in the face and shows me how off target my incorrect suspicions are... and all I can do is bang my forehead and say "Duh!"
I have always been fascinated by gyroscopes (there is a toy one on my desk as I type this). And I had the idea that the unrolling loop had some similar properties, or at least half of 'em. Your videos show that the particle doesn't even travel in half a circle... maybe 1/4 at most?
I have been daydreaming about this shit ever since!
With appreciation and apologies to Ray Charles…
“If it wasn’t for AI, we wouldn’t have no I at all.”
“If it wasn’t for AI, we wouldn’t have no I at all.”
- gordonjudd
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Re: Tension Discontinuity /DN
Graeme,A single point doesn't even follow a 1/4 circle in a normal "semi-circular loop". It has a sort of "1/4 parabolic" path, shedding forward velocity rapidly.
That is the case for an earth frame, but if you use an inertial frame (constant velocity in one direction) attached to the front of the loop the particles do appear to follow a quasi-semi-circular path. An example of what your clip 10 video would look like in a moving frame is shown below. Not sure why it is breaking up at the end using Vimeo.
[media]https://vimeo.com/manage/videos/566346145[/media]
a moving frame should give the same results as the ones you get earth frame, and is typically used in most analysis papers to make the analysis much more straightforward.
Can you give your reasoning for this statement?It's a fallacy to think the size of the loop influences the aerodynamics of the loop.
Gordy
Re: Tension Discontinuity /DN
Hi Torsten
I did check with the work energy model from Gatti Bono. The set of momentum equations (horizontal and angular momentum) exactly matches the work energy one, with the same input data of course. That was a perequisite before moving forward and test pull back situations.
Merlin
I did check with the work energy model from Gatti Bono. The set of momentum equations (horizontal and angular momentum) exactly matches the work energy one, with the same input data of course. That was a perequisite before moving forward and test pull back situations.
Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
Charles Ritz, A Flyfisher's Life