Simplistic aerodynamic modelling of wings

[nichols46]

Hie

I'm currently working to put together a simple aeroelastic structual tool for use in design of aircfat wings. However most of my experience, and teh experience of my colleagues is in structures, so i'm hoping someone can provide a bit of advice on the aerodynamic side of things.

The model needs to be quick to run, as it's a highly iterative process and we want to keep run times down.

Initially I've considered using tornado, which is an open source VLM method. but I've read that run times can increase if the geometry becomes comlex.

Obviously if we use a simpler method for complex geometry the results will not be as accurate, but we may need to live with the inaccuracies in order to keep run times down.

I know Prandtl's lifting line theory become inaccurate for swept wings, but can anyone quantify (or point me in the direction of) how inaccurate it becomes?

And if as a very simplistic approach I just calcaulted the CL and Cm of each section of the wing using thin aerofoil theory is there a way to obtain the distribution over the whole wing? Is there a tip loss factor that can be applied to wings to account for their aspect ratio? How rough would the answers be?

I'd be really grateful for any tips or advice,

Thanks in advance

Sara

 

[btrueblood]

Google the term "NASA Technical Report Server". Go to the first or second link, and type the following search term:

"spinner drag propellor"

You could also add "hub" and "rotor" in various combinations with the above.

But, that first search gave these gems as some of the top ten hits:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091383_1993091383.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091667_1993091667.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092657_1993092657.pdf

and

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091803_1993091803.pdf

There's probably a later NASA report in the pile, somewhere, that summarizes all the prior NACA work. But, getting copies of the NASA reports is a bit trickier, as they aren't in a free server like the NACA reports, and you'll have to work out how to get copies (try a uni library, or pay for them...)

 

[Sparweb]

Sounds like you want a "black box" airplane wing design program. I hope you have an idea of the large number of input variables that would go into such a thing. It's been done before - you might find that the path of least resistance. Maybe WH Mason has already written one.

I think a better approach (than getting reports from the NACA server, useful though they are) would be to buy an aerodynamics textbook such as "Introduction to Flight" by Anderson, or "Airplane Aerodynamics" by Dommasch, Sherbey, and Connolly. Then you would have a better picture of how to build mathematical models of aircraft wings or propellors.

Steven Fahey, CET