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Re: [Phys-L] BP or CE?



Nodding to Roger Linsell's demo clips at
https://www.youtube.com/playlist?list=PLLKB_7Zd6leNJmORn6HHcF78o2ucquf0U
I insert what I take to be his categorizations below, where possible.

On 12/22/2014 4:50 PM, Anthony Lapinski wrote:
I checked many (not all) of my paper textbooks, and none of them the
Coanda effect.
I only heard about the CE from phys-l in the past few years. So if there
is much confusion
here, then why aren't these effects clearly spelled out in physics books?

Many of us do classroom demos to show BP, but I think some of them might
show the CE instead.
What about these, which I sort of put into categories? Which effect
dominates?

perfume atomizer
blow between two hanging cans
Venturi / Bernoulli
spin on baseball pitch
dimples on golf ball
Wiffle ball
Magnus effect (with enhanced boundary layer activation for the golf ball.)
shape of plane wing
blow over paper
boomerang
Coanda /Bernoulli.
vacuum cleaner and beach ball
toy blow ball pipe
vertical Dyson fan and balloon
air blower and toilet paper roll
Unsure of configuration details: vacuum blowing down on beach ball to lift it, or blowing up to suspend it?? etc...

What demos illustrate each?
J Denker replied:
Reasonable Bernoulli examples include:
-- ordinary airfoils.
-- Pitot-static system.
-- Magnus effect (spinning cylinder + true airspeed).
-- Venturi geometry (probably).
-- levitating disk, as previously discussed.
However, he seems to have lost a desired negation, in the paragraph below:
In contrast, if it looks like a narrow high-velocity jet impinging
on a curved surface, it's probably Coanda. If the same jet
impinging on a flat surface doesn't produce the effect, it's a
dead giveaway that Coanda is involved.



Brian Whatcott Altus OK