Question aboutTrefftz plane analysis?
Question aboutTrefftz plane analysis?
(OP)
Hello every one
I would like to learn more about trefftz plane theory which is used to calculate induced drag.
Is it an effective method to calculate induced drag?
can i used it with propeller and wind turbine instead of an aircraft wing?
thanks in advance
I would like to learn more about trefftz plane theory which is used to calculate induced drag.
Is it an effective method to calculate induced drag?
can i used it with propeller and wind turbine instead of an aircraft wing?
thanks in advance





RE: Question aboutTrefftz plane analysis?
http://www.edforall.net/index.php/engineering-a-te...
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: Question aboutTrefftz plane analysis?
RE: Question aboutTrefftz plane analysis?
Regards
Pat
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RE: Question aboutTrefftz plane analysis?
RE: Question aboutTrefftz plane analysis?
I asked two more question which i can't answer by reading 3 pages, what i need is an opinion based on experience.
Appreciate your help and i have no intention to break any rules.
RE: Question aboutTrefftz plane analysis?
so too berkshire's (so he gives you a link to the material).
if you're saying you've read the material but don't "get it", i'd suggest starting with an earlier lecture and see if that helps. maybe if you ask a specific question about the derivation, maybe someone will give you a nice response (but don't count on it !).
assuming you know the material, and you're asking is it applicable to propeller drag analysis, i'd point out the initial assumptions "invisid, incompressible" fliud. i'd suggest that flow around a propeller is not incompressible (tip speeds are often close to mach 1), and so it probably doesn't apply (unless they derive a compressible version later in the lecture.
RE: Question aboutTrefftz plane analysis?
This is far from my area of expertise, but I think a propeller can be treated as a wing, except that the air speed over the wing increases with dia as does effective pitch unless that is corrected for in the design.
Even if you are not a student which I will quite happily take your word for, simplistic or very wide general questions still tend to downgrade the site and attract student style posts which we mostly really don't want to bother with.
Regards
Pat
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RE: Question aboutTrefftz plane analysis?
RE: Question aboutTrefftz plane analysis?
Assume the OP means HAWT, or do you actually mean VAWT?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Question aboutTrefftz plane analysis?
rb1957 This method used - as i understand - to calculate the induced drag, and since the induced is caused by the downwash which lead to change the angle of the Lift which lead to another component of lift in the free stream direction namely induced drag.
All this has nothing to do with the compressibility effect, so i think the incompressible, inviscid, irrational flow assumption - even for high speed propeller - is safe.
MiketheEngineer What i am trying to say is: all i want is the NAME of the book so i can BUY it
RE: Question aboutTrefftz plane analysis?
don't we use CFD for this (calculating drag) these days ? looking quickly at the calc, you need the flow veolcity over some control volume, something you'll only get from CFD; but then don't CFD codes calc drag for you ?
maybe go to the MIT opencourseware site (the origin of the previous link) and look for similar lectures, maybe there are references and examples ?
maybe you're too focused on this specific analysis ? maybe google "induced drag".
"to calculate the induced drag, and since the induced is caused by the downwash which lead to change the angle of the Lift which lead to another component of lift in the free stream direction namely induced drag." ... this seems circular ! induced drag is drag caused by lift (as opposed to form drag) you use it to determine the drag polar of a wing.
RE: Question aboutTrefftz plane analysis?
RE: Question aboutTrefftz plane analysis?
are you trying to do some hand calcs to verify the CFD ?
i found this site "http://www.pdas.com/induced.html" by googling "induced drag worked example". it has links to some more work/books on the subject.
even googling "trefftz plane analysis" got lots of hits (surprisingly) so there are sources out there (that you can find for yourself).
is this for school ??