NASA text/article on jet engine performance modeling

[Phil Bunch]

http://gltrs.grc.nasa.gov/Citations.aspx?id=3061

Among other things, there is a link to a 175 page PDF article on jet engine performance and the associated modeling at the above web page, and this document link is provided below for convenience.  

The text quality is adequate but not ideal quality - perhaps it was scanned at excessively low resolution.   Lots of technical info here for those who would like to understand jet engine performance in a bit more depth and/or to understand more about how such things are mathematically modeled.

http://gltrs.grc.nasa.gov/reports/1998/CR-1998-206597.pdf

I thought about putting this in the A380 incident topic since it was referred to on pprune where they continue their discussion of the A380's recent uncontained engine failure, etc.  However, this is a general purpose engine modeling and analysis document, and is not specific to the A380 or the recent engine failure.

I haven't read the article in depth yet but I always wonder about the accuracy of such computational modeling efforts.  In all fairness, comparing model predictions vs measured performance would necessarily be the topic of another large research effort and publication.

[Zinger]

I always wonder about the accuracy of such computational modeling efforts.  In all fairness, comparing model predictions vs measured performance would necessarily be the topic of another large research effort and publication.

Once the human race is able to solve Kutta's  three simple airflow differential equations, the calculated method would be accurate. Till then, we need to utilize computational modelling and test them in cells and later in flight.

[Phil Bunch]

I found this Wikipedia article to be interesting and informative in its balanced discussion of competing theories of lift.  

http://en.wikipedia.org/wiki/Lift_%28force%29

Especially see the animated airflow figure, its caption and the associated discussion.  Too often one sees only Bernoulli effects or excessively simplified Newton's laws of motion, in generic lift explanations.

I gave some thought to applying to graduate school in a program at my university that emphasized fluid mechanics and related areas of study, many years ago.  Instead, I obtained my PhD in medical physics (diagnostic radiology).  I always wonder about paths not taken in life.  I also wonder about paths taken.  (grins)

[Jeroen Hoppenbrouwers]

What, you take your paths consciously?   :-P

[Phil Bunch]

What, you take your paths consciously?   :-P

Well, it *seems* like it at the time, but in retrospect ALL the major path decisions seem to have a large random component!  I can't figure how to reconcile the illusion of making carefully thought out conscious decisions with the unavoidable reality of path selections being substantially or perhaps totally random.  

For example - one's spouse/partner choice "path" is heavily influenced by what city (or virtual internet society) you inhabit when one falls in love or whatever.    If you're living in London, your future spouse/partner is likely to be living there too.  Someone living in Bangkok would not be a likely candidate.

Mathematically, it seems that many aspects of one's life are mostly described by chaos and is heavily influenced by slight changes in initial conditions.    
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Speaking of chaos and accidental events, the A380 pilot who helped land the thing after an engine exploded failed his check ride since he received advice from others during the check ride.  Somehow, it seems unfair that he helped pulled off such a major "save the plane and pax" effort without loss of life and yet failed the check ride.   I guess it just wasn't his day.  Would he still have failed if he had ordered everyone else to stay silent and let him handle it without assistance or advice?