[HN Gopher] Quieting the Global Growl
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Quieting the Global Growl
Author : tintinnabula
Score : 61 points
Date : 2024-06-07 05:21 UTC (17 hours ago)
(HTM) web link (hakaimagazine.com)
(TXT) w3m dump (hakaimagazine.com)
| lioeters wrote:
| Recently I saw a video of a dolphin that came up to a boat and
| was imitating the sound of a boat motor. It looked playful, but
| perhaps it was complaining about all the noise.
| telesilla wrote:
| It think it was an orca, I saw this yesterday also. We're all
| curious what it's trying to communicate, but I like the idea of
| it repeating back to us what is a very annoying sound to them.
| rtkwe wrote:
| "This is what you sound like idiot, those aren't even words!"
| -That Orca Probably
|
| I've been highly amused at the tales of Orca's attacking
| yachts over the last few years too.
| cess11 wrote:
| Yacht in this context typically refers to a rather small
| sailing boat. It affects small-scale fishers and things
| like that, not the large motor yachts rich people have.
| dkarl wrote:
| I remember watching a nature TV show as a kid in which the
| presenter waxed lyrical about the way a group of dolphins
| took one dolphin's vocalization and repeated it and riffed
| on it, claiming that they were improvising musically
| together like a jazz group. I remember thinking that it was
| a very optimistic assumption, and it was just as likely
| that the rest of the dolphin were mocking and bullying the
| first dolphin.
|
| That train of thought probably says something about what I
| was going through at the time, but given other things we've
| learned about dolphins, I wouldn't discount my idea.
| cess11 wrote:
| Orcas are dolphins.
| lioeters wrote:
| Thanks for pointing it out, I didn't know that orcas are
| dolphins too. The one I saw was like a "bottlenose dolphin"
| with the classic dolphin shape and color.
|
| > The orca, or killer whale, is a toothed whale that is the
| largest member of the oceanic dolphin family.
|
| > Oceanic dolphins include several big species whose common
| names contain "whale" rather than "dolphin", such as the
| round-headed whales including the false killer whale and
| pilot whale). The Delphinidae family also includes the
| porpoise, beluga whale, and narwhal.
| blackeyeblitzar wrote:
| If you have the chance to listen to actual boat noise from an
| underwater microphone, you'll be surprised at how loud it is and
| how far sound can travel. It's less of a problem with pleasure
| boats and more of an issue with commercial ones like container
| ships. Other sounds that are loud underwater and harmful for
| animals include wind turbine noise (from spinning giant blades)
| and sonar pings.
| ck2 wrote:
| US Navy (and certainly others) kill many dolphins, whales and
| other sea life with their high powered sonar.
|
| US also has high powered ultra low frequency radio (ELF) for
| communication to subs and that's got to be insane to wildlife.
|
| https://en.wikipedia.org/wiki/Project_Sanguine
| dingnuts wrote:
| sound and radio are of course waves in completely different
| media. why would low frequency radio waves be insane to
| wildlife? it's not like it's microwave (which would cook
| them) or pressure (sound) which directly physically damages
| their organs. almost by definition low frequency radio waves
| are low energy, so I don't see how this would be more
| dangerous to Flipper than my Wi-Fi router is to me
| d3w3y wrote:
| Well, some people _do_ think their Wi-Fi routers can hurt
| them ... maybe we should make tinfoil hats for the
| cephalopods.
| bee_rider wrote:
| Huh, sharks pick up EM signals, right? I wonder what they
| think of this stuff
|
| But just to be clear, I don't think we should suppose it is
| damaging and try to ask the military to stop using it (good
| luck, lol). It could be worth looking into though.
| nativeit wrote:
| I mean, we all pick up EM signals. The frequency range is
| the distinction, I think.
| bee_rider wrote:
| Sure, but sharks use them as a sense. We all pick up
| photons in the sense that we can all feel the warmth of
| the sun on our skin, but also, it is sometimes
| interesting to think about how people who aren't blind
| perceive light.
| blackeyeblitzar wrote:
| I'm talking about sound not electromagnetics. It's like a
| torture for marine life to be surrounded by constant noise.
| Many also use sound to communicate or locate.
| jeffbee wrote:
| According to this (highly interesting) paper I just read, it
| seems that the operating sounds of wind turbines come from the
| gearbox, which makes more sense to me because the blades of
| offshore turbines are turning very slowly. Also according to
| the same paper, the operating noises of offshore wind farms are
| probably not significant.
|
| https://www.int-res.com/articles/meps2006/309/m309p279.pdf
|
| As an aside, I love discovering a researcher with such a
| delightful niche. How many people are out there researching
| "Acoustically mediated fin whale mating"? Amazing humans.
| blackeyeblitzar wrote:
| My experience disagrees with that claim. But I suggest an
| easier way to verify this, which is to just go to YouTube and
| look at videos of the sound produced by wind turbines on
| land. You will hear the distinct loud woosh sound of the
| actual blades and not the gearbox. Personally, I feel a lot
| of the academic denial around this noise issue is from people
| with an activist goal.
| jeffbee wrote:
| You seem to have missed the point of the research, which is
| all about underwater sound propagation.
| bee_rider wrote:
| YouTube videos are not very difficult to edit. If you
| search YouTube for "noisy windmills," I'm sure you'll
| get... something.
|
| Anyway windmills are all over the place, lots of people
| have had the experience of being near them. If they make
| too much noise, that's a problem of course, but I think
| lots of people can verify the existence of non-noisy ones
| by virtue of having seen them in person. So, sure, loud
| designs should be avoided since there are perfectly good
| alternatives.
| teitoklien wrote:
| > YouTube videos are not very difficult to edit.
|
| And academic papers are not difficult to fudge up with
| edited fraudulent data [1].
|
| Even Ivy League colleges are committing rampant fraud
| sometimes for activism sometimes just to get attention
| and get more papers published.
|
| It's sad that we're at a time where academia is as
| untrustworthy as random videos on YouTube.
|
| But i agree with noiseless windmills part, they should be
| promoted more instead of noisy ones that will discourage
| more clean energy initiatives.
|
| [1](https://retractionwatch.com/)
| bee_rider wrote:
| I mean, nobody would say the academic publishing
| ecosystem is super healthy (every academic hates it, for
| one). But the existence of something like "retraction
| watch" points to the fact that these aren't really
| comparable ecosystems. Nobody need bothers to catalogue
| the lies on YouTube because that's an impossible and
| pointless task.
|
| The academic process has always been messy and political,
| and yet universities do keep churning out research and
| students.
| teitoklien wrote:
| > The academic process has always been messy and
| political, and yet universities do keep churning out
| research and students.
|
| The youtube process has always been messy and political,
| and yet new creators do keep churning out great content
| that people love watching and spreading awareness about
| various issues.
|
| :)
|
| The youtube show : "Undecided by Matt Ferrell" is my
| favourite
| ben_w wrote:
| Lotta clickbait, too. They need it to keep earning, even
| if they don't like it.
|
| I recall Tom Scott saying there was one video he
| basically couldn't make, because the climax was switching
| on a big light, which was actually silent, but it felt
| wrong unless he dubbed a sound over that and such dubbing
| was against his editorial standard.
| bee_rider wrote:
| That's interesting. Without knowing what the switch was,
| I guess it is hard to say, but a switch that kicked off
| some big process silently seems like it could be really
| dramatic and cool.
| advisedwang wrote:
| Wind turbines are moving a lot faster than they appear. E.g.
| Vestas v164 [1] rotates only at max 12 times per minute so
| looks slow. But because it has 80m blades, the tip speed is
| up to 100 meters per second (230mph). That's 1/3rd the speed
| of sound! That can generate a lot of noise.
|
| [1] https://en.wind-turbine-models.com/turbines/1419-mhi-
| vestas-...
| jeffbee wrote:
| That explains why they would make broadband noises but not
| peaky high-q noises like the ones in the paper.
| sevensor wrote:
| I'm not a fluid mechanics guy, but all that cavitation from the
| screws seems like preventably wasted energy, not to mention a
| huge source of potential surface wear.
| schiffern wrote:
| Yes you're right.
|
| I'm surprised PBCF isn't more common. It essentially reduces
| swirl and cavitation in the central vortex, converting it
| into additional thrust while also reducing shaft torque. It's
| an inexpensive retrofit (payoff time <6 mo) with broad
| compatibility, and the swap can be done while unloading with
| no downtime. And yes, it reduces rudder surface erosion which
| is caused by cavitation.
|
| Seems like a no-brainer. Maybe folks just aren't aware of the
| technology?
|
| https://www.youtube.com/watch?v=a8PjWSeLUzY
| UniverseHacker wrote:
| Fascinating, I'm really into boating and sailing and have
| never heard of this- no consumer grade engines or boats
| that I know of have this.
| sevensor wrote:
| Wow, that's awesome! Looks like a big win all-around. Save
| money, save fuel, save wear.
| UniverseHacker wrote:
| A lot of the noise is from the combustion engines themselves-
| exhaust often releases underwater, and the engine vibration
| transmits through the hull.
| dredmorbius wrote:
| Correct on both counts.
|
| Nuclear submarines feature very large, many-bladed,
| specially-shaped propellers _often turning very slowly_ to
| reduce both noise and wear (though more the former: stealth
| is key to submarine operations).
|
| Cavitation on hydraulic and steam turbines, as well as other
| hydraulic mechanisms, is a major source of wear and failure.
| Keep in mind that cavitation is equivalent to boiling, and
| involves both high (if localised) temperatures _and_ extreme
| pressure fluctuations as cavitation bubbles form and
| collapse.
|
| A couple of discussions from both perspectives:
|
| <https://archive.navalsubleague.org/2012/a-century-of-
| america...>
|
| <https://www.sciencedirect.com/science/article/abs/pii/S00298
| ...>
|
| For nuclear submarines, overall efficiency isn't
| _termendously_ important, as _when the sub needs to move
| quickly_ the powerplant can turn out a heck of a lot of
| power.
|
| Checking just now to confirm powerplant output, I'm learning
| that the _Virginia_ class of hunter-killer submarines, for
| which _both_ quiet operation _and_ speed for pursuit are
| concerns) use pump-jet propulsors rather than traditional
| bladed propellors, specifically to reduce cavitation:
|
| <https://en.wikipedia.org/wiki/Virginia-
| class_submarine#Propu...>
|
| Top speed is in excess of 25 knots. (I suspect _considerably_
| in excess, though
|
| Powerplant is a 210 MW nuclear reactor, 280,000 HP
| equivalent. By contrast the Maersk E-class containership
| (largest in the world until 2012) have an 81 MW (fossil-fuel
| based) powerplant, 109,000 HP equivalent. The still-larger
| Triple-Es have two 31 MW engines (for lower total output),
| and the current size giant _CSCL Globe_ 69.7 MW.
|
| <https://en.wikipedia.org/wiki/E-class_container_ship>
|
| <https://en.wikipedia.org/wiki/Triple_E-class_container_ship>
|
| <https://en.wikipedia.org/wiki/CSCL_Globe>
|
| And the fastest known military submarine seems to have been
| the K-222 Soviet Project 661 "Anchar", which could reach
| 41-45 knots (about 50 mph) submirged. The K-222 is slightly
| shorter than the _Virginia_ class, and as hull-length has a
| strong effect on top speed (see hull speed:
| <https://en.wikipedia.org/wiki/Hull_speed>, though how this
| relates to submarines I'm uncertain, see also Froude number:
| <https://en.wikipedia.org/wiki/Froude_number>), I suspect
| _Virginia_ class boats could likely achieve similar speeds
| should the need exist.
| dylan604 wrote:
| It's one of the things that I find fascinating about Naval
| tech. From the sonar from each boat to the network of devices
| like SOSUS net[0], you have to be very good and deliberate to
| sneak around in the oceans.
|
| [0]https://en.wikipedia.org/wiki/SOSUS
| emilecantin wrote:
| I've done some snorkeling on coral reefs in the Bahamas, and
| it's crazy how far you can hear boats. Once you learn what
| sound they make (it's completely different underwater), you can
| hear one very clearly but when you pop your head up it's way
| off in the distance. And this is just for smaller, outboard-
| powered boats.
|
| I've never really had the chance to hear a big ship underwater,
| but my home is right by the St-Lawrence seaway (the one they
| talk about in the article) and when it's quiet at night I can
| feel the rumble they make through the ground when one passes in
| front of the house.
| UniverseHacker wrote:
| Even the above water noise is awful... I am sensitive to noise,
| and do engineless sailing partly because the sound of motors is
| awful, and ruins the fun of boating for me.
| te0006 wrote:
| Try a modern electric motor. There are some really quiet ones
| now.
| edem wrote:
| when i was a kid we often camped near a river. every morning i
| heard music but i couldn't identify the source. "it comes from
| the other side" my uncle said. that day i learned how far sound
| can travel in the water
| sdenton4 wrote:
| If you make incredibly loud noises above water, humans will
| complain, and you'll end up reducing the noise, due to some
| combination of workplace safety regulations, litigious neighbors,
| and self-regulation.
|
| People don't experience underwater noise directly, though, and so
| it is allowed to be arbitrarily loud and has gone almost
| completely unchecked, and is undoubtedly harmful got marine
| ecosystems. It is thought to be a major factor in whale
| beachings, for example.
| spinach wrote:
| Humans in cities have also got used to the noise. Go from a
| quiet forest or rural area in the middle of nowhere to a city
| or residential area where you have cars, trains, lawn mowers,
| leaf blowers, air planes, loud barking dogs, etc. It's
| shockingly noisy. It's surprising that people don't want to do
| more about the noise pollution but it seems many just got used
| to it.
| chasd00 wrote:
| on a tangent, I was living about 15min SW of DFW airport when
| 9/11 happened. When the FAA grounded all air traffic i
| remember going outside and thinking how strange it was not
| hearing planes in the sky. I had become acclimated to all the
| air traffic and when there was none it was pretty eery.
| marssaxman wrote:
| Rural areas can be noisy, too, depending on the ecosystem:
| birds, frogs, crickets, and cicadas can all kick up quite a
| ruckus. One can get used to just about anything.
| ericd wrote:
| True, those sounds are somehow less grating, though. I hate
| two stroke motors with a passion.
| mycologos wrote:
| If you're a layperson interested in these sensory questions, I
| highly recommend the book _An Immense World_ by Ed Yong. It 's a
| 400-something page tour through the many senses animals have and
| we (mostly) don't. It might have the highest density of truly
| cool animal facts per page of anything I've ever read, despite
| being written for adults who maybe haven't considered themselves
| the audience for fun animal facts in decades.
| cactusplant7374 wrote:
| Which fact did you find the most interesting?
| pixelmonkey wrote:
| +1, a truly great book.
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