"A common misconception is that Coandă effect is demonstrated when a stream of tap water flows over the back of a spoon held lightly in the stream and the spoon is pulled into the stream. While the flow looks very similar to the air flow over the ping pong ball above (if one could see the air flow), the cause is not really the Coandă effect. This particular demonstration is dominated by surface tension." - wikipedia.
You can also see the different flow regimes for the water coming out of the spigot. The flow seems to be first laminar, and then with the increased flow rate, the water enters the transition regime and the finally the fully turbulent regime. Overall, very good experiment!
There is still debate as to which better describes the principles of flight, but most aerodynamicists believe that the Coanda effect describes lift of an airplane wing to a greater degree than the Bernoulli principle. Really, both principles are different ways of describing essentially the same net result --Newton's laws of motion (e.g., F=ma), but one better describes the aerodynamic than the other.
This is the Bernoulli principle - think lift on the upper curved top surface of an aircraft wing. If you understand that the atmosphere is a fluid medium just like water only less dense, you will understand they've simply used the backside of a spoon for the curved surface, turned everything sideways, and called it something else. The stream of water is providing sideways "lift" because it effectively reduces the air pressure on the opposite side of the spoon.
No, this effect is not adequately described by the Bernoulli principle. The viscosity of the fluid (air in the case of an airplane wing, or tap water in the above experiment) causes the fluid to adhere to the curved surface due to a gradient in friction (highest friction at the surface of the spoon) and directs the flow beyond the trailing edge at whatever trajectory it departed the trailing edge from. The result is a fluid flow departing the spoon at a greater angle than vertical.
Water and air behave the same, I see. I Hadn't considered that water and air could possibly exhibit pressure equalizing between them. I wonder if the same effect would occure in a vaccum.
No it wouldn't because there is no fluid to obtain lift or steering in. Satellites and space shuttle orbiters use reaction control system thrusters for steering because any wings would be obsolete in vacuum.
no, the Coanda effect is present when any fluid (i.e. liquid or gaseous, separately) runs along a solid surface. The flaps of the airplane function in gas only and the rudders of a submarine in function in liquid only.
@yutewang
"A common misconception is that Coandă effect is demonstrated when a stream of tap water flows over the back of a spoon held lightly in the stream and the spoon is pulled into the stream. While the flow looks very similar to the air flow over the ping pong ball above (if one could see the air flow), the cause is not really the Coandă effect. This particular demonstration is dominated by surface tension." - wikipedia.
kazioo2 3 weeks ago
Really great idea, excellent demonstration.
Sylvanian1000 7 months ago
Excellent, demonstrative experiment!
cashmab 1 year ago
You can also see the different flow regimes for the water coming out of the spigot. The flow seems to be first laminar, and then with the increased flow rate, the water enters the transition regime and the finally the fully turbulent regime. Overall, very good experiment!
NYFlyer1 2 years ago
Cool experiment!!!
vanepico 2 years ago
So is it the coanda effect or the bernoulli's principle that explains why an airplane flies?
thanks.
Niko1917 3 years ago
There is still debate as to which better describes the principles of flight, but most aerodynamicists believe that the Coanda effect describes lift of an airplane wing to a greater degree than the Bernoulli principle. Really, both principles are different ways of describing essentially the same net result --Newton's laws of motion (e.g., F=ma), but one better describes the aerodynamic than the other.
cashmab 1 year ago
This is the Bernoulli principle - think lift on the upper curved top surface of an aircraft wing. If you understand that the atmosphere is a fluid medium just like water only less dense, you will understand they've simply used the backside of a spoon for the curved surface, turned everything sideways, and called it something else. The stream of water is providing sideways "lift" because it effectively reduces the air pressure on the opposite side of the spoon.
sigung01 3 years ago
No, this effect is not adequately described by the Bernoulli principle. The viscosity of the fluid (air in the case of an airplane wing, or tap water in the above experiment) causes the fluid to adhere to the curved surface due to a gradient in friction (highest friction at the surface of the spoon) and directs the flow beyond the trailing edge at whatever trajectory it departed the trailing edge from. The result is a fluid flow departing the spoon at a greater angle than vertical.
cashmab 1 year ago
The horizontal component of that diverted flow vector is what holds the spoon in the stream of water.
cashmab 1 year ago
Wow, never thought of that, thank you for your insightful comment.
sigung01 1 year ago
wow, is the effect used practically anywhere?
PerfectBlindness 4 years ago
on airplanes' wings to make them fly!! =)
kiscky 3 years ago 2
Water and air behave the same, I see. I Hadn't considered that water and air could possibly exhibit pressure equalizing between them. I wonder if the same effect would occure in a vaccum.
PerfectBlindness 3 years ago
No it wouldn't because there is no fluid to obtain lift or steering in. Satellites and space shuttle orbiters use reaction control system thrusters for steering because any wings would be obsolete in vacuum.
McQuackor 3 years ago
I was remarking upon this coanada effect demonstration having involved both water and the air around it. Does the air need to be there?
PerfectBlindness 3 years ago
no, the Coanda effect is present when any fluid (i.e. liquid or gaseous, separately) runs along a solid surface. The flaps of the airplane function in gas only and the rudders of a submarine in function in liquid only.
McQuackor 3 years ago
thanks, I couldn't tell from the video. That's a real help. :D
PerfectBlindness 3 years ago
excellent demonstration, we appreciate your contribution
crazydandan 4 years ago 3