Some Fields May Not Have Been Properly Introduced

Like a lot of mysteries in science, the BN effect was introduced as
one type of phenomena when it was really something else.
The way a problem is originally presented often determines how long or
if it will be solved. That is often the most important part of the
solution according to Einstein and others.
This _mindset_ led everyone astray for a long time. I looked at the
BN effect very casually shortly before -- but not after -- I started
working on particle bed displacers in free cylinder "salt shaker"
Stirlings and I wondered if it might have to do with larger particles
having a higher Reynolds number.
I was originally misled too.
The BN effect and the particle displacer were like skew lines in my
mind. I may have thought about mixing various size particles in the
displacer but I never thought about the BN effect issue, even though I
had recently looked at it. I never thought that there might or might
not be a nexus.
What triggered the solution was the BN effect being raised as an issue
in the particle bed displacer _after_ I had spent so much time trying
to deal with the assymetry of the particle displacer cycle.
The assymetry issue occupied so much of my mind it dislodged the old
prejudices that got the BN effect off to a bad start.
Supposing a lot of empirical fields are like that? Supposing
continuum mechanics, for example, was somehow misintroduced and that's
why Newton messed up his lift equation and why they are still coming
up with considerable advances in a field where everything should have
been well settled years ago?
After Phelps made that spectacular victory back in March everyone was
diagraming his stroke to determine the success of his swimming style.
Phelps probably just tried a lot of different things to determine what
worked. That's just the way things seem to get done in fluid
mechanics.
In fields like structures or mechanics you will never be upstaged by
some empiricist.
Bret Cahill
Reply to
Bret Cahill
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Dear Bret Cahill:
...
Actually you *always* get upstaged by some empiricist. That is what "code", "standard", and "regulation" are... empirical guidelines to design.
As to expecting school to provide you with interest in every possible topic, you have to remember they are supposed to teach you how to learn, not "teach you everything there is to know, and make you feel interested in every topic". I would not sit still for such indoctrination, could not afford the time it would take, would not want to give up all other outside activities while such new interest was formed... nor could society come to a standstill while every student was required to know and be interested in the current state of affairs in all fields.
You might find such techniques helpful:
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We depend on each other for shared experience. That is the "leg up" that intelligence provides to those on the evolutionary ladder that have it. Sir Issac had his giants upon whose shoulders he stood.
Do you personally have to know everything there is to know? There are also companies that have services that will invoke specialists in certain disciplines, Nelco and TelTech (I think) among them.
David A. Smith
Reply to
dlzc
Machinery includes more than structures and dynamics but give some examples though and we'll look at them. I do not deny something could have been overlooked.
A structure example that wouldn't hold would be the stayed bridge and tower crane that were popular in Europe before becoming widespread in the U. S. It's not that American engineers were ignorant of the possibility of the structures. It's just that different high profile structures were grandfathered in. Bridges have architectural value and cranes must be an industry accepted design.
In sharp contrast, GE made a dramatic 25% efficiency improvement in an aircraft engine -- billions and billions in jet fuel -- and completely upstaged Rolls Royce. There's no need to pander to popular opinion with aircraft engines. Even the customers cannot spot any differences.
If RR engineers knew it was possible, they most certainly would have done it.
Bret Cahill
Reply to
Bret Cahill
Dear Bret Cahill:
...
I am asking what your experience is. I'd like to make you review all the empirical relationships that you use every day, and simply are not (currently) aware of.
Architectural and civil designs are very much at the end of the barrel of a gun, since we graduate more lawyers than anything else. They canot much afford to break new ground, because mistakes / missteps can have heavy financial penalties.
Threaded fasteners depend very much on empirical guidelines / directives. Design of joints depend very much on empirical guidelines / directives. Arrangements of mechanisms depend very much on empirical guidelines / directives.
Not that each has not been analyzed since, but daily practice is drawing from an established source (ASTM, ASME, MSA, etc.) for empirically-based sources.
Do you test every component part to failure, prior to "shipping" it?
We also stand on the shoulders of giants. We do not engineer things up from atoms, but depend on "customary" or "empirical" relations to make our further steps to progress.
David A. Smith
David A. Smith
Reply to
N:dlzc D:aol T:com (dlzc)
Airbus A380. Airbus structural engineering said "the wing will fail at 1.5 times limit load." That was a wing designed using FEA. When they actually tested it, it failed at something like 1.48.
Percentage wise, that's pretty good but, since the law says though shall exceed 1.5, it was a big deal. Empiricists win.
Tom.
Reply to
Tom S.
Wrong. RR knew full well it was possible. RR just has a different design philosophy (or used to). They generally design for minimum total cost of ownership. Pratt & Whitney generally designs for maximum performance. GE generally designs for minimum fuel consumption.
They all know exactly what the other guys are doing but, as with most things in aviation, there is no one right answer so none of them are right or wrong.
Tom.
Reply to
Tom S.
Fuel is 80% of the entire operating cost of an airline. Competing against 125 passenger miles/gallon with 100 pmpg just ain't gonna happen in the razor thin profit margin airline industry.
If RR knew what they were doing at GE then they just had really stupid management.
Bret Cahill
Reply to
Bret Cahill
Dear Bret Cahill:
...
Yes, and I provided a link before. Triz. Combine disparate empirical / analytical knowledgebases, to generate new solution spaces.
David A. Smith
Reply to
N:dlzc D:aol T:com (dlzc)
No, fuel is 80% of the cost of operating an air*plane*. For an airline, it's must lower (typically around 40%). The number one and two cost at most airlines is fuel and labour (it flip-flops depending on which airline you are talking about). Maintenance is usually third.
Of course not. But the different in efficiency between GE and RR is only a few percent, at most.
Not really stupid, just didn't guess the direction of the market as well as GE did. There are plenty of operators out there who still choose RR over GE. RR is running about 50/50 with GE on the 787, I believe.
Tom.
Reply to
Tom S.
Hmmmm....someone who is unsure of the concept of transport fuel efficiency and engine fuel efficiency, I guess? Alternatively, someone who is unsure in which units jet fuel usage is quoted?
Your guess is as good as mine, certainly.
Brian Whatcott Altus OK
Reply to
Brian Whatcott
The airframe has some advances but most of it is the counter rotating engine.
It's unambiguous: RR Airbus is trying to compete against 125 pmpg with 100 pmpg.
There is _no such thing_ as a TWENTY FIVE PERCENT advantage in the airline industry.
London/Brussels will have to bail them out.
Bret Cahill
Reply to
Bret Cahill
Dear Bret Cahill:
RR also has a counter-rotating engine, the Trent 900, and (purportedly) had it before GE.
That is true. And in this case, you appear to be all wet:
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The GEnx is being designed to bring a 15 percent improvement in specific fuel consumption over GE's highly successfully CF6-80C2 engine
... note that GE is not claiming 25% increase, and are comparing only to their own (older) product.
Has happened before, and will happen again. Same story with Boeing.
David A. Smith
Reply to
N:dlzc D:aol T:com (dlzc)
And there's no such thing as 15% either.
Western civilization is doomed. I'm going to learn Chinese.
Bret Cahill
Reply to
Bret Cahill
It's 25% higher.
No, it's not. I've got the TSFC figures for the GENX and the newest Trent right here.
If you're comparing across engine generations or airframes, then you may pick up a 25% difference, but that's pretty much a kumquats to watermelons comparison then.
Tom.
Reply to
Tom S.
No, it's not. As was correctly pointed out, RR has had counter-rotation for decades. It's only a new thing for GE.
That's totally ambiguous. RR and Airbus aren't the same company, and they both make a whole bunch of products. "RR Airbus" could refer to dozens of possible products...which ones are you talking about?
Tom.
Reply to
Tom S.

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