Sharkoon's "Golf Ball" Inspired Case-Fan
Sharkoon released the latest fan in its Silent Eagle "golf ball" series.
Wednesday Sharkoon revealed the 140-mm Silent Eagle 800 fan, the latest addition to its "Silent Eagle" case fan series. What makes this particular series unique is that the rotor blades have the surface texture of a golf ball. Although the fan certainly won't help with your golf swing, the small, round dimples are said to increase the amount of airflow by reducing drag. [as proven by The Mythbusters--Ed.]
"The Sharkoon Silent Eagle 800 rotates at 800 rpm, moving 93.85 cubic meters of air per hour while at a noise level of 12.4 decibels," the company said in a press release. "The power usage is rated at 0.1 amps and 12 volts. The white propeller and black frame case fan rotates in a rugged metal bearing and weighs 162 grams."
The company said that the fan can be connected to the power supply or motherboard. Also included with the fan is a 3pin/4pin adapter cable, a 3pin connector cable protected by a rubber hose, and a separate cable for monitoring the number of revolutions. To help with the noise reduction, four fan screws and rubber bolts are also supplied.
The Silent Eagle 800 is one of many models offered in the Silent Eagle series. Other than this 140-mm version, consumers can also purchase an illuminated LED model or the SE version which includes a modular cable system.
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hum.. these have been around for quite some time!
Where is the silent eagle series available in the US? I emailed Sharkoon just the other day and only the SE series is available in the US, and they rotate about 40% slower than the Silent Eagle 2000 (120mm models being compared.)
this reminds me of the myth buster episode where the "golf ball" the exterior of a car which ends up actually upping the gas mileage.
"93.85 cubic meters of air per hour"
55 CFM. typical of 140mm fans at 800rpm. not too impressive. but quiet.
I really don't think this applies to fans considering they have a sharp cut off. If you follow the air movement on the fan, tell me how it is going to reduce air resistance. More likely it will increase considering the dimples are going to slow the air down (which is the whole point of them). However I'm thinking that because this gives it more air resistance it is better, since it acts like a physically bigger fan.
WTF? I have have Sharkoon's Golf Ball design fans for years... Maybe these are new low power, low speed, even lower noise editions but the story shouldn't focus on the design as that is the one part that isn't new!
@the_punkinator
Anyone can Google the concept and find the article you're paraphrasing:
http://wings.avkids.com/Book/Sport [...] lf-01.html
It's usually a good idea to understand it from a possible point of view instead of reading the article trying to use it to justify a pre-convieved idea that MythBusters are morons.
The concept doesn't apply to airfoils.
edit* Thanks for clearing that up with the comment edit
batwing design FTW!
Holy time warp!
I think i have seen this like 5+ years ago!!!
WTF? I have have Sharkoon's Golf Ball design fans for years... Maybe these are new low power, low speed, even lower noise editions but the story shouldn't focus on the design as that is the one part that isn't new!
But who elsee knows they exist?
Fyi anyone that wants them can get them at performance pcs
@the_punkinator
Anyone can Google the concept and find the article you're paraphrasing:
http://wings.avkids.com/Book/Sport [...] lf-01.html
It's usually a good idea to understand it from a possible point of view instead of reading the article trying to use it to justify a pre-convieved idea that MythBusters are morons.
Well first of all I didn't google crap. If you didn't know not all people have to google stuff to get the knowledge to comment.
Also I deleted that since I figured it interfered with my main point. Did you know "MythBusters" "proved" that Archimedes could not have built a steam cannon. Did you know that even back then Archimedes was 50 times smarter then they will ever be? But apparently they "Busted" it, they could have just said that "from the looks of things he wouldn't of been able to do it" but no that's not what the losers who watch the show would want.
Silverstone has been using golf ball fans in some of the HTPC cases to reduce noise.
@the_punkinatorAnyone can Google the concept and find the article you're paraphrasing:http://wings.avkids.com/Book/Sport [...] lf-01.htmlIt's usually a good idea to understand it from a possible point of view instead of reading the article trying to use it to justify a pre-convieved idea that MythBusters are morons.
You must note that in the article you linked they are discussing spheres, not blades. The aerodynamics of a blade are completely different than that of a sphere. Also, if you decreased the drag on the fan, it wouldn't do it's job as well. If the blades were flat, the air resistance would be virtually zero, which, if decreasing air resistance was the goal, is what they would do. But when the fan blades are flat they won't actually push/pull any air. These dimples are definitely to increase the air resistance thereby increasing the amount of air moved.
I have a silverstone fan that is just like that
I have a 120mm cooler master fan that pushes out 90cfm's at 19db and they're 10 bucks a peice, best fan i've ever had!.
http://xoxide.com/coolermaster-r4-120mmfan-green.html
green red and blue flavors for you're liking.
You must note that in the article you linked they are discussing spheres, not blades. The aerodynamics of a blade are completely different than that of a sphere. Also, if you decreased the drag on the fan, it wouldn't do it's job as well. If the blades were flat, the air resistance would be virtually zero, which, if decreasing air resistance was the goal, is what they would do. But when the fan blades are flat they won't actually push/pull any air. These dimples are definitely to increase the air resistance thereby increasing the amount of air moved.
You're confusing up profile drag and lift-induced drag. Wikipedia will be able to explain them better than me, but the basic concept is that threre are two primary kinds of drag on a wing/propeller shaped object like a fan: Profile drag is the smaller of the two. It arises because you're pushing the blades through the air and overcoming the friction between the air and the blade's surface. You'd get profile drag even if the blades were flat and weren't pushing any air.
Lift-induced drag is caused by the blades "pushing" the air. The greater the angle of attack of the blades, the more air they push, and the higher the lift-induced drag. So if the blades were flat, you'd get zero lift induced drag (but still get profile drag), but in an actual fan with the blades angled, you'd get both profile drag and lift-induced drag (which is the larger of the two).
By adding dimples, you're not increasing air flow "because you are increasing the resistance", but rather the dimples decrease profile drag (because like a golf ball, the dimples make the air flow turbulent instead of laminar, so you reduce air resistance). The fact that resistance is reduced (not increased) was written in the last line of the first paragraph of the article. My guess is that lift-induced drag remains unchanged by the dimples. So there you go you'll get the same amount of airflow but need a less powerful motor to overcome the combined drag, leading to quieter running.
I have golfball dimpled fans in my coolermaster ft02 case.
I have golfball dimpled fans in my coolermaster ft02 case.
sorry, i meant silverstone.
i read a review on such fan, found that it was quieter but at the expense of lower CFM.
"93.85 cubic meters of air per hour"55 CFM. typical of 140mm fans at 800rpm. not too impressive. but quiet.
At least it's quiet.... I have to agree with you there.
You're confusing up profile drag and lift-induced drag. Wikipedia will be able to explain them better than me, but the basic concept is that threre are two primary kinds of drag on a wing/propeller shaped object like a fan: Profile drag is the smaller of the two. It arises because you're pushing the blades through the air and overcoming the friction between the air and the blade's surface. You'd get profile drag even if the blades were flat and weren't pushing any air.Lift-induced drag is caused by the blades "pushing" the air. The greater the angle of attack of the blades, the more air they push, and the higher the lift-induced drag. So if the blades were flat, you'd get zero lift induced drag (but still get profile drag), but in an actual fan with the blades angled, you'd get both profile drag and lift-induced drag (which is the larger of the two).By adding dimples, you're not increasing air flow "because you are increasing the resistance", but rather the dimples decrease profile drag (because like a golf ball, the dimples make the air flow turbulent instead of laminar, so you reduce air resistance). The fact that resistance is reduced (not increased) was written in the last line of the first paragraph of the article. My guess is that lift-induced drag remains unchanged by the dimples. So there you go you'll get the same amount of airflow but need a less powerful motor to overcome the combined drag, leading to quieter running.
Except that dimples do not always reduce profile drag.
The reason that the dimples work on a golf ball is that turbulent boundary layers are more resistant to flow separation. This means that the flow stays attached to the surface of the ball farther around the back of it, causing it to have a smaller region of stagnant air behind it. Less stagnant air = less drag.
With an airfoil or streamlined object, such as a fan blade, a turbulent boundary layer is not beneficial. Although it is still resistant to flow separation, an airfoil or streamlined shape is not prone to flow separation regardless, even with laminar flow. Because flow separation is not a problem, skin friction drag is the majority of the profile drag (rather than pressure drag, as with a sphere). With a turbulent boundary layer, which is what the dimples are meant to induce, the skin friction drag actually increases. There's a reason that airplanes aren't dimpled. In fact, on the Boeing 787 (now in testing), a tremendous amount of effort went towards decreasing the amount of turbulence on the front part of the wings (especially on the engines), maintaining laminar flow as long as possible to reduce drag.
(Oh, and induced drag is effectively unchanged)
Will it survived long enough for enthusiast?
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Except that dimples do not always reduce profile drag.The reason that the dimples work on a golf ball is that turbulent boundary layers are more resistant to flow separation. This means that the flow stays attached to the surface of the ball farther around the back of it, causing it to have a smaller region of stagnant air behind it. Less stagnant air = less drag.With an airfoil or streamlined object, such as a fan blade, a turbulent boundary layer is not beneficial. Although it is still resistant to flow separation, an airfoil or streamlined shape is not prone to flow separation regardless, even with laminar flow. Because flow separation is not a problem, skin friction drag is the majority of the profile drag (rather than pressure drag, as with a sphere). With a turbulent boundary layer, which is what the dimples are meant to induce, the skin friction drag actually increases. There's a reason that airplanes aren't dimpled. In fact, on the Boeing 787 (now in testing), a tremendous amount of effort went towards decreasing the amount of turbulence on the front part of the wings (especially on the engines), maintaining laminar flow as long as possible to reduce drag. (Oh, and induced drag is effectively unchanged)
Everything you said makes sense, but if we assume that the dimples on the fan do have beneficial effects (as the mythbusters seem to have proven), then how do the benefits come about? I was wrong to compare a sphere to a streamlined shape, so I agree with your statement that skin friction drag (profile drag) increases. More drag is generally worse, so how then do the dimples give this fan an advantage? It's starting to look like a marketing gimmick to me... can you explain how dimples make it better?
"93.85 cubic meters of air per hour"55 CFM. typical of 140mm fans at 800rpm. not too impressive. but quiet.
93.85 m^3/hr = 55.2 CFM (95.83m^3/hr * 35.3ft^3/1m^3 * 1hr/60M)
Looking around the web (newegg.com and www.performance-pcs.com) for other fans 140mm @ 750 - 1000 RPM ...
NF-P14 FLX: 750 RPM / 41.93 CFM
XCLIO 256 Color Fan: 800 RPM / 31.25 CFM
MASSCOOL SLC-FD14025: 800 RPM / 27.2 CFM
Yate Loon D14SL-12: 1000 RPM / 46.9 CFM
Lian Li CF-1409A: 900 RPM / 60.2 CFM
Aerocool Streamliner: 1000 RPM / 54.7 CFM
Enermax T.B.SILENCE: 750 RPM / 45.4 CFM
Scythe "KAZE MARU 2": 800 RPM / 43.50 CFM
It's only "beaten" by the Lian Li fan and edges out the Areocool. However, both of those are running 20% - 33% faster. I'd say it is impressive.
EDIT only 12.5% - 25% faster ... had 750 RPM on the brain.
They were featured at computex.
Everything you said makes sense, but if we assume that the dimples on the fan do have beneficial effects (as the mythbusters seem to have proven), then how do the benefits come about? I was wrong to compare a sphere to a streamlined shape, so I agree with your statement that skin friction drag (profile drag) increases. More drag is generally worse, so how then do the dimples give this fan an advantage? It's starting to look like a marketing gimmick to me... can you explain how dimples make it better?
I have to say, I'm quite tempted to conclude that the dimples make it worse, and are there simply as a marketing gimmick.
Honestly, the best fans that I've seen from an aerodynamic perspective (and from an airflow per noise perspective) are the Noctuas. I have those in my case, and I'm always amazed at how much air they push for their noise. Expensive though.
Agreed, +1, Noctua FTW
They do a hard job in tough condition but keep my rig chilly at the worst of times