Bernoulli's Effect (Page 2): Well, this might have all been an exercise in mind bending. I checked with the meteorology department at Rutgers University, and, according to one of them...

toxdoc42

Well, this might have all been an exercise in mind bending. I checked with the meteorology department at Rutgers University, and, according to one of them, the winds changed to being from the WNW after the Nor Easter passed. The media never corrected their reports. More information may still come in, since I reached out to several meteorologists.

"I assume you are talking about the snow on March 14. Actually, the winds were from the WNW that day, so the snow was indeed on the windward side of the trees. This nor'easter had already passed us (and was stalled out over New England) by the time the snow was falling. We did have the customary NE winds (and some rain) on the 13th as the storm approached."

Beard43 Loc: End of the Oregon Trail

I've rebuilt a lot of carburetor in my time.

Ron

Dikdik Loc: Winnipeg, Canada

Same thing, but different... has to do with the changes in pressure with velocity for fluids... just like a carb...

olddutch Loc: Beloit, Wisconsin

lukevaliant wrote:

this makes sense that's how a carburator introduces air to the system(venturi).

Bernoulli‘s principle states that were velocity is greatest pressure is least, and in a carburetor the main discharge nozzle is placed in the center of the Venturi, where the pressure is least, and it dries fuel out of the car out of the carburetor and then reduces it into the air that’s going through the carburetor. And this is a very brief description and in aircraft mechanic school we spent almost all most of week on Bernoulli’s principles. That was 65 years ago

Toby

Toby wrote:

A lot of fancy descriptions and math. If you would like to see this principle in practice do the following. Cut a piece of paper about 1" wide and 6" long. Pinch the 1" end between your forefinger and thumb. Wrap the paper over the top of your fingers and the hold your forefinger up to your mouth with the top of the paper at the same level as the top of your bottom lip. What happens to the paper?? It is pulled up (lift) just like on the top surface of an airplane wing.

Sorry I forgot to mention that you need to blow across the paper while holding it up to your lip. Dummy me.

PhotogHobbyist Loc: Bradford, PA

toxdoc42 wrote:

I am really not sure where this posting belongs, but it started as an observation from my apartment window, then became a photographic effort, then an effort to explain the phenomenon I saw. The images are suboptimal, i was inside, not daring to go outside and the snow was really swirling around at high speeds.

I Lived my entire career in medicine, discovering things that were obvious, but that others missed. This included being the first to report a serial killer working in a hospital which ended up as the conviction of what some consider the most prolific serial murderer in the US history. If interested, see my book: Medical Toxicology, Antidotes and Anecdotes, published by Springer in 2017.

To make a long story short, there was a severe Nor-Eastern predicted for much of the country last week. In my area of NJ, Short Hills, we dodged the major bullet, with no real accumulation of snow. We did get the strong winds, allegedly gusting to in the 40 mph range. With it came swirling snow. When I looked out of my apartment window i was struck by something I had never seen before. The snow had accumulated on the vertical portion of every tree in sight, but, NOT ON THE NE side, in reality, the western side of the trees were accumulating the snow.

This made no sense to me at the time, if the winds were coming from the NE driving the snow, why did the snow not accumulate on that side. I looked up what the definition of a Nor-easter was to be sure that i was correct, that the winds come from the NE. Conforming that, I reached out to people I thought were smarter than me for help. There was silence from them all.

I postulated that perhaps, the tree trunk was acting like the leading edge of a wing and that the side opposite was developing a "vacuum effect" from the rapid rushing wind, the Bernoulli effect. I finally reached a meteorologist who said she had never been asked that question before, but felt that my explanation was probably sound.

https://www.khanacademy.org/science/physics/fluids/fluid-dynamics/a/what-is-bernoullis-equation

https://www.skybrary.aero/articles/bernoullis-principle

I am really not sure where this posting belongs, b... (show quote)

I did not recognize it as the Bournelli effect, but your description made me think if an automobile traviling in a snow strom, and not a really heavy one. When driving through falling snow a significant amount of snow accumulates on the rear of the auto, moreso on vehicles with flatter rear surfaces like pickup truck tailgates, larger SUVs and box trucks or semi trailiers.

Toby

PhotogHobbyist wrote:

I did not recognize it as the Bournelli effect, but your description made me think if an automobile traviling in a snow strom, and not a really heavy one. When driving through falling snow a significant amount of snow accumulates on the rear of the auto, moreso on vehicles with flatter rear surfaces like pickup truck tailgates, larger SUVs and box trucks or semi trailiers.

And next to trees and snow fences

Lucian Loc: From Wales, living in Ohio

It is the fact that the wind changed in your area. You won't get snow sticking to the back of a tree, the snow will impact the side that it is hitting and the tree will see a build up on that side being hit. Next time, go out and stand by the trees and see what way the wind and snow is hitting you. It has nothing to do with vacuums or anything else.

Lucian Loc: From Wales, living in Ohio

As for and airplanes wing, or a propellor or helicopter rotor blade, they all have a similar shape. If you look at a cross section of any of them, you will see that the top surface is curved and the bottom surface is relatively flat. Since the top surface is curved, if you straightened it out, you would see that it is longer than the bottom surface.
As air hits the leading edge (front), it has to be divided up, with some air going over the top and some going underneath along the bottom surface.

The air going over the top surface of these shapes obviously has a greater distance to travel than air running along the bottom surface. If the top and bottom air ran along those two surfaces at the same speed, the bottom layer would get to the back or trailing edge before the top surface air arrived. Physics tells us that this can't happen because if it did, we would get a constant vacuum at the trailing edge which would make a noise when the two air layers finally met.

Therefore, the air running over the top of the wing, prop, rotor, has to speed up in order to meet the bottom air layer at the same time, at the trailing edge. Since the top air must speed up, that also means that it creates an area of lower pressure than the bottom air layer. Since air likes to keep itself equal, the higher pressure lower air wants to equal out that top lower pressure air.

When that speeded up top layer of air creates that low pressure area, the wing effectively gets sucked up into the sky on that section. Now if you can image it, that longer top wing section is being pulled or sucked up into the sky and for the most part, this is what creates the lift of that wing, to make it go up into the sky. Now that bottom surface of the wing is also at an angle of attack to the oncoming air and of course, it will be hit by that air and the air will be deflected downwards, thereby also helping to push that section of the wing up into the sky.

This means that a wing gets helped on both top and bottom surfaces of its skin, to achieve lift into the sky. With that said, the longer top surface of the wing in the low pressure air has the greater lifting power, so more suction than deflected air from the bottom surface, goes to making that wing lift into the air to make an aircraft fly, or a prop give force to make the aircraft move forward through the air, or a rotor blade give lift to that entire spinning disk, to lift that helicopter into the sky.

That low pressure area on the top surface of the wing is very slight but very effective to allow an aircraft to achieve lift. Just to get you to understand the suction taking place along the top wing surface, lets look at a huge Boeing 747, which has a very large wing surface area. The suction taking place along that top surface of its wing is less, per square inch, than the suction a baby exerts on a dummy they are sucking, in their mouth. In the UK we call those things dummies. I think in the US you call them a pacifier.

So, image that, every square inch of that top surface wing area of a 747, that low pressure air is exerting less suction per Sq. inch, than a baby sucking on their dummy, yet, it still gets lifted off the ground and takes to the sky in flight. It is really quite amazing when you stop to think about it, the principles of flight and the physics that are going on in such a simple thing as a wing's airfoil shape, moving through the air.

I've been a pilot for more years than I've been a photographer and a flight instructor too, and it still amazes me when I think of what is going on with a wing, to make it fly. Hope this explanation has helped those that may not have fully understood what is going on as a wing moves through the air. I've tried to simplify it for everyone so as not to give too detailed of an explanation.

Dannj

Lucian wrote:

As for and airplanes wing, or a propellor or helicopter rotor blade, they all have a similar shape. If you look at a cross section of any of them, you will see that the top surface is curved and the bottom surface is relatively flat. Since the top surface is curved, if you straightened it out, you would see that it is longer than the bottom surface.
As air hits the leading edge (front), it has to be divided up, with some air going over the top and some going underneath along the bottom surface.

The air going over the top surface of these shapes obviously has a greater distance to travel than air running along the bottom surface. If the top and bottom air ran along those two surfaces at the same speed, the bottom layer would get to the back or trailing edge before the top surface air arrived. Physics tells us that this can't happen because if it did, we would get a constant vacuum at the trailing edge which would make a noise when the two air layers finally met.

Therefore, the air running over the top of the wing, prop, rotor, has to speed up in order to meet the bottom air layer at the same time, at the trailing edge. Since the top air must speed up, that also means that it creates an area of lower pressure than the bottom air layer. Since air likes to keep itself equal, the higher pressure lower air wants to equal out that top lower pressure air.

When that speeded up top layer of air creates that low pressure area, the wing effectively gets sucked up into the sky on that section. Now if you can image it, that longer top wing section is being pulled or sucked up into the sky and for the most part, this is what creates the lift of that wing, to make it go up into the sky. Now that bottom surface of the wing is also at an angle of attack to the oncoming air and of course, it will be hit by that air and the air will be deflected downwards, thereby also helping to push that section of the wing up into the sky.

This means that a wing gets helped on both top and bottom surfaces of its skin, to achieve lift into the sky. With that said, the longer top surface of the wing in the low pressure air has the greater lifting power, so more suction than deflected air from the bottom surface, goes to making that wing lift into the air to make an aircraft fly, or a prop give force to make the aircraft move forward through the air, or a rotor blade give lift to that entire spinning disk, to lift that helicopter into the sky.

That low pressure area on the top surface of the wing is very slight but very effective to allow an aircraft to achieve lift. Just to get you to understand the suction taking place along the top wing surface, lets look at a huge Boeing 747, which has a very large wing surface area. The suction taking place along that top surface of its wing is less, per square inch, than the suction a baby exerts on a dummy they are sucking, in their mouth. In the UK we call those things dummies. I think in the US you call them a pacifier.

So, image that, every square inch of that top surface wing area of a 747, that low pressure air is exerting less suction per Sq. inch, than a baby sucking on their dummy, yet, it still gets lifted off the ground and takes to the sky in flight. It is really quite amazing when you stop to think about it, the principles of flight and the physics that are going on in such a simple thing as a wing's airfoil shape, moving through the air.

I've been a pilot for more years than I've been a photographer and a flight instructor too, and it still amazes me when I think of what is going on with a wing, to make it fly. Hope this explanation has helped those that may not have fully understood what is going on as a wing moves through the air. I've tried to simplify it for everyone so as not to give too detailed of an explanation.

As for and airplanes wing, or a propellor or helic... (show quote)

Your explanation certainly helped me! Thanks! Hope you don’t mind if I use it so folks will think I actually know what I’m talking about😊

Lucian Loc: From Wales, living in Ohio

Dannj wrote:

Your explanation certainly helped me! Thanks! Hope you don’t mind if I use it so folks will think I actually know what I’m talking about😊

Big Smile on this end!

lukevaliant Loc: gloucester city,n. j.

what lucian said