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“Fluid gears” invention offers promise for improving mechanical devices

phys.org

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Re: “Fluid gears” invention offers promise for improving mechanical devices

#51

Post by adrian_b »

mjmas wrote: post #14
Someone wrote: post #12

Earlier quoted context omitted.

> Ever driven a vehicle with an automatic transmission rather than a manual gearshift with a clutch? Then you almost certainly used a fluid coupling Are you sure? https://en.wikipedia.org/wiki/Continuously_variable_transmis... : “The most common type of CVT uses a V-belt which runs between two variable-diameter pulleys. […] A belt-driven design offers approximately 88% efficiency, which, while lower than that of a ma…

CVT != Automatic transmission (which is generally hydraulic) https://en.wikipedia.org/wiki/Automatic_transmission#Hydraul...

CVT is not the same as "automatic transmission", but it is a subtype of automatic transmission, i.e. CVT is a kind of automatic transmission, but there are also other kinds of automatic transmissions, which are more frequently used.

"Automatic transmission" just means that you do not change gears manually, which is also true for CVT.

Re: “Fluid gears” invention offers promise for improving mechanical devices

#52

Post by dang »

bwoah wrote: post #46
dang wrote: post #44

Earlier quoted context omitted.

Can someone suggest a better (i.e. more accurate and neutral) title?

Mapping out How Fluid Mechanical Spin-coupling Interactions Depend on Proximity, Confinement, and Flow State Alternate: New Ways to Understand, Control, and Exploit Hydrodynamic Spin-spin Interactions in Applications The article doesn't really deliver on either headline, but that's the fault of the article, not the study.

The limit is 80 chars and I'm not sure how to squeeze those in. I've taken a crack at something simpler in the title above. Does it work?

Re: “Fluid gears” invention offers promise for improving mechanical devices

#53

Post by gnabgib »

dang wrote: post #44
snow_flake wrote: post #27

The phys.org article and headlines are misleading, the authors did not investigate systems to actually transmit torque. From what I gather, the interesting findings are the parameters for co-rotation and counterrotation of the driving and driven cylinder, depending on the Reynolds number, distance and so on. To illustrate one of the images of their publication: https://i.imgur.com/m8P2iVw.png

Can someone suggest a better (i.e. more accurate and neutral) title?

From the original source: Scientists Put Teeth Into Water-Driven Gears https://www.nyu.edu/about/news-publications/news/2026/januar...

(Can't tell what the submission title was, but the byline (with quotes) works too: “Fluid gears” invention offers promise for improving mechanical devices)

Re: “Fluid gears” invention offers promise for improving mechanical devices

#54

Post by dang »

gnabgib wrote: post #53
dang wrote: post #44

Earlier quoted context omitted.

Can someone suggest a better (i.e. more accurate and neutral) title?

From the original source: Scientists Put Teeth Into Water-Driven Gears https://www.nyu.edu/about/news-publications/news/2026/januar... (Can't tell what the submission title was, but the byline (with quotes) works too: “Fluid gears” invention offers promise for improving mechanical devices )

Ok, let's try the second one. Thanks!

Re: “Fluid gears” invention offers promise for improving mechanical devices

#55

Post by gregors »

HPsquared wrote: post #21
bluGill wrote: post #17

Earlier quoted context omitted.

Many automatics these days are manual transmissions with a computer controlling the clutch. They have nothing in common with the slushboxes of old, the oil is just for lubrication.

Even slushboxes tend to aggressively lock up the torque converter. It's usually only in a "fluid dynamics" mode for brief moments. (Except maybe on a gentle hill start)

It's worth mentioning hard acceleration causes a torque multiplication to occur in torque converters vs a slow acceleration does not (check me on that). Once locked up, multiplication no longer occurs. Thank you hot rod magazines of the 90's.
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