News An ordinary squirt of canned air achieves supersonic speeds - engineer spots telltale shock diamonds

[Admin]

A precision engineering and machining YouTuber noticed telltale ‘shock diamonds’ in the stream emitted by his Staples-branded canned air and felt compelled to investigate further. Using a Schlieren imaging setup the YouTuber confirmed that the air duster was pushing out a supersonic flow of gas.

An ordinary squirt of canned air achieves supersonic speeds - engineer spots telltale shock diamonds : Read more

 

[vanadiel007]

Excellent if you wish to blow the components off your motherboard.
Now it makes sense they are producing shielded motherboards. It's to protect them from the blast of canned air.

 

[pixelpusher220]

Reminds me of the question

"Name the first human invention to break the sound barrier"

The bullwhip

 

[punkncat]

If the contents of the can are going supersonic, why are we not hearing a crack or boom?

I do not hold any degree or training in fluid dynamics (etc.) so this is a legitimate ask.

 

[USAFRet]

If the contents of the can are going supersonic, why are we not hearing a crack or boom?

I do not hold any degree or training in fluid dynamics (etc.) so this is a legitimate ask.

Much too small an amount of material (air).

 

[punkncat]

Much too small an amount of material (air).

I am going to come off like an idiot, lol.

I don't doubt this at all. As I say I have no training in said. I do understand a bit about "boom sticks" and know that if you are going to successfully use a suppressor, that you must have a "rock" that doesn't exceed the speed of sound.
Would this be to infer that if you had a small enough projectile (or is it the density of said) that determines the amount of displacement of atmosphere which actually causes the sound as it moves back into its previous state/location?

 

[USAFRet]

I am going to come off like an idiot, lol.

I don't doubt this at all. As I say I have no training in said. I do understand a bit about "boom sticks" and know that if you are going to successfully use a suppressor, that you must have a "rock" that doesn't exceed the speed of sound.
Would this be to infer that if you had a small enough projectile (or is it the density of said) that determines the amount of displacement of atmosphere which actually causes the sound as it moves back into its previous state/location?

The molecules of air coming out of the can are only supersonic for a very short range. I would expect a couple of inches, maybe.
In addition, not a lot of mass.

We hear a supersonic bullet, because that is many many times more mass than the airflow coming out of the can.

 

[domih]

I'm using the opportunity of this article to again remind casual users with this warning.

WARNING
DO NOT blow an air can toward a fan and make it spin very fast. Yes, the fan noise is entertaining BUT you actually make the fan rotating way beyond what it is designed to support. The result is damaging and you significantly reduce the life span of you fan.

If you want to air dust a fan, hold the blades still with a finger, a piece of wood or whatever.

 

[thently]

No I will not stop this.

 

[vanadiel007]

It does give a satisfying sound. Worth it to me!

 

[peachpuff]

I'm using the opportunity of this article to again remind casual users with this warning.

WARNING
DO NOT blow an air can toward a fan and make it spin very fast. Yes, the fan noise is entertaining BUT you actually make the fan rotating way beyond what it is designed to support. The result is damaging and you significantly reduce the life span of you fan.

If you want to air dust a fan, hold the blades still with a finger, a piece of wood or whatever.

Party pooper!

 

[Nikolay Mihaylov]

Canned air cans do not actually contain air. That would require too much pressure in order to hold reasonable amounts of gas. You need something that turns into a liquid. I always though they clean so well, because the hydrocarbons it contains act as solvent.

https://en.wikipedia.org/wiki/Gas_duster

 

[Geezer760]

I just use an air compressor and very soft make-up brushes, why pay for expensive canned air.

 

[Notton]

Sonic booms happen when a solid object creates a pressure wave in front and behind while moving through air.

Shock diamonds don't produce a crack or boom, because it's a fluid. It only creates a pressure wave in front. The displaced air gets filled in by the fluid. It's still loud.

If you've seen rocket engine or jet engine testing, you might have seen them producing shock diamonds while stationary.

 

[USAFRet]

I just use an air compressor and very soft make-up brushes, why pay for expensive canned air.

Depending on the compressor, they can also spit out oil.

 

[JeffreyP55]

A precision engineering and machining YouTuber noticed telltale ‘shock diamonds’ in the stream emitted by his Staples-branded canned air and felt compelled to investigate further. Using a Schlieren imaging setup the YouTuber confirmed that the air duster was pushing out a supersonic flow of gas.

An ordinary squirt of canned air achieves supersonic speeds - engineer spots telltale shock diamonds : Read more

That's nice. I have been using the exhaust side of my shopVac for the past 15 years. No need to buy an aerosol can. Never a broken part or bent anything. Cleans the dust bunnies like crazy. Just take the PC outdoors.

 

[JeffreyP55]

I'm using the opportunity of this article to again remind casual users with this warning.

WARNING
DO NOT blow an air can toward a fan and make it spin very fast. Yes, the fan noise is entertaining BUT you actually make the fan rotating way beyond what it is designed to support. The result is damaging and you significantly reduce the life span of you fan.

If you want to air dust a fan, hold the blades still with a finger, a piece of wood or whatever.

Been blowing fans clean for 15 years and another 10 with my old hoover constellation exhaust ports at insane speeds. The constellation does not have wheels. 1959 UFO inspired vac rides on a cushion of air from the exhaust post. No damage to report. Some fans in my old machine I built in 2014? No fan problems to this day. Maybe someday... I will keep you posted

 

[punkncat]

I just use an air compressor and very soft make-up brushes, why pay for expensive canned air.

Make sure to drain the tank and use a water filter on the output side. Air compressor tanks fill with water due to humidity and will blow droplets of water out. Also, if this is a compressor head that uses oil (some are "oil-less") you should consider filtering for that as well.

One of the plus sides of the canned air are there are no contaminants to blow onto whatever you are working with.

I personally use a cheap electric leaf blower, some static free brushes (a new addition) and wipes or microfiber rag on some parts.

 

[JeffreyP55]

A precision engineering and machining YouTuber noticed telltale ‘shock diamonds’ in the stream emitted by his Staples-branded canned air and felt compelled to investigate further. Using a Schlieren imaging setup the YouTuber confirmed that the air duster was pushing out a supersonic flow of gas.

An ordinary squirt of canned air achieves supersonic speeds - engineer spots telltale shock diamonds : Read more

Oh look, diamonds!

https://imgur.com/a/0uUawkg

View: https://imgur.com/a/0uUawkg

A precision engineering and machining YouTuber noticed telltale ‘shock diamonds’ in the stream emitted by his Staples-branded canned air and felt compelled to investigate further. Using a Schlieren imaging setup the YouTuber confirmed that the air duster was pushing out a supersonic flow of gas.

An ordinary squirt of canned air achieves supersonic speeds - engineer spots telltale shock diamonds : Read more