Increasing amplitude of transverse waves

[Paul Arden]

Hi guys,

I'm sure this has been covered but I've forgotten the answer

Why/how do transverse waves in the fly leg, as in the case of a tailing loop, increase in amplitude as they propagate?

Many thanks,
Paul

[gordonjudd]

Why/how do transverse waves in the fly leg, as in the case of a tailing loop, increase in amplitude as they propagate?

Paul,
I think Alejandro's explanation was that the transverse wave has momentum in the direction of the initiating force impulse.

Thus the loop velocity in that direction will stay about the same (aside from the slowing caused by drag effects). That means its distance will increase with time. As a consequence its loop length will increase with time.

Gordy

[Paul Arden]

Thanks Gordy!

Since we discussed this last year, this concept of transverse wave propagation has sit in my head and is of great value. It applies to some forms of negative curves, the trailing loop, tracking faults and also the fly hitting the shoulder.

Aitor and Alejandro both understood this stuff some time ago. But it takes a while for me for it to sink in!

Cheers, Paul

[Hal Jordan]

Here are a few simple experiments to try. Find a fly line with a very short, or even no, rear taper on the head. Lay the head out in a straight line on the ground along with about 6 - 8 feet of the running line. Pick up the running line in your hand at this point (don't use the rod) and wave the line as hard and as fast as you can with the intention of creating waves that propagate into the head. Note what happens to the waves when they propagate in to the head. Now do the same thing in reverse - try and make waves propagate from the head to the running line. See any difference?

Now another experiment - get a friend and a really long slinky (or a long extension cord if you don't have a slinky). Each of you hold one end of the slinky and stretch it out as far as it will go. Each of you create a half wave in the slinky from their end. Do this two ways - first with the half wave oriented in the same direction (but obviously travelling in opposite directions). What happens when the two pulses cross each other? Now do the same thing but with the pulses oriented 180 degrees from each other. What happens when the pulses cross this time?

Cheers