Is the cast itself a transverse wave?

[gordonjudd]

Vince,
As an aerosystemes engineer, what would you call the force that is lifting this inclined plate due to the change in the momentum of the water flow from a fire hose? When they cranked up the flow from the fire hose to increase the momentum change, it actually lifted him off his feet.


The same thing is going on with the drag induced lift of a climbing loop shape.

Gordy

[Merlin]

Vince

There is no such thing as alternative physics (but it can be argued on Twitter or Facebook by now), I guess you imagine what I think of those media

Merlin

[VGB]

Vince,
As an aerosystemes engineer, what would you call the force that is lifting this inclined plate due to the change in the momentum of the water flow from a fire hose? When they cranked up the flow from the fire hose to increase the momentum change, it actually lifted him off his feet.


The same thing is going on with the drag induced lift of a climbing loop shape.

Gordy

Gordy

We have been through this before, stop going to high school sites.

Vince

[VGB]

Vince

There is no such thing as alternative physics (but it can be argued on Twitter or Facebook by now), I guess you imagine what I think of those media

Merlin

Merlin

I would like to agree with you but lift and drag are clearly defined concepts.

Vince

[VGB]

Here you go Gordy, the problem with the "skipping stone theory of lift" that is used in your video.

https://www.grc.nasa.gov/www/k-12/airplane/wrong2.html

I have shown the free stream flow in green, the resultant force due to the plate angle and the resolved components of lift and drag on the red and blue axes, in accordance with aerodynamic convention. Do you think the result would have been the same if he had been holding a flexible distributed mass instead of a rigid distributed mass?

Vince

[Graeme H]

Drs. Gatti-Bono and Perkins provided that answer in a short note years ago.
effect of loop shape on drag induced lift of fly line
Gordy

I've read that paper. Some interesting numeric modelling ...

Can you tell me why my loop doesn't veer sharply to the right when I cast with a side loop please? If loop lift has enough force to counteract gravity when the loop is vertical, why isn't there enough force to turn my loop even vaguely when it's on the side?

What is keeping that loop up when it's on its side, not receiving any loop lift?

Cheers,
Graeme

[gordonjudd]

Can you tell me why my loop doesn't veer sharply to the right when I cast with a side loop please? If loop lift has enough force to counteract gravity when the loop is vertical, why isn't there enough force to turn my loop even vaguely when it's on the side?

Graeme,
Good question, I would think it should if you are able to get a climbing loop shape that looks like a sexyloop turned on it side.

Try taking a bird's eye video (with a light line that will be more affected by drag) and let's see what a measurement shows.

What is keeping that loop up when it's on its side, not receiving any loop lift?

There is tension pulling up on the rod leg. Try putting you tip on the ground after the loop is formed and see how much the loop drops. A video will help with this example as well.

Gordy

[gordonjudd]

Do you think the result would have been the same if he had been holding a flexible distributed mass instead of a rigid distributed mass?

Vince,
Not if the moving medium is coming from a fire hose, but if it is an inclined section of fly line that has tension and is traveling through air then Dr. Gatti-Bono's analysis would say it will have some lift.

You could do a related experiment by hitting a short section of hanging fly line with the exhaust stream from a vacuum cleaner and see if it rises at some angle where the downward gravitational force on the fly line reaches an equilibrium angle that depends on the drag-induced lift it has from the air stream.

A video of that would be instructive as well, but I am betting that the line will swing up to some equilibrium angle that depends on the velocity of the air stream (even though you will have some flutter of the free end).

Gordy

[gordonjudd]

Can someone point out how air drag lifts a falling object please?
and
I've read that paper. Some interesting numeric modelling ...

Graeme,
If you were familiar with Dr Gatti-Bono's analysis I would be interested why you asked that question.

Do you think her analysis is wrong, and there no such thing as a climbing loop shape?

Gordy

[Paul Arden]

Can you tell me why my loop doesn't veer sharply to the right when I cast with a side loop please?

If the underlying principle is correct there will be a veering to the right on a high speed cast. I cannot confirm or deny this. I will have a play tomorrow.

Cheers, Paul