SU2: Open-source CFD Software from Stanford's Aerospace Dept.

From the Stanford University website:

At a recent demonstration, the Stanford team debuted "Stanford University Unstructured" (SU2), an open-source application that models the effects of fluids moving over aerodynamic surfaces such as fuselages, hulls, propellers, rotors, wings, rockets and re-entry vehicles.

Dubbed SU2 for short, the application incorporates everything engineers need to perform a complete design loop for optimizing the shapes of aerospace systems.  While commercial programs offering similar capabilities are available, they can be prohibitively expensive. SU2, on the other hand,  can be downloaded for free from the lab's website.

Source: http://engineering.stanford.edu/news/stanford-aero-engineers-debut-open-source-fluid-dynamics-design-application

Update: Version 1.1 of SU2 is available as of 06/29/12

Download via: http://su2.stanford.edu/news/news_release1p1.html

Many thanks to @FlightTestFact for the link!

Reference Text: "Summary of Airfoil Data" - National Advisory Committee For Aeronautics

Old but valuable, airfoil theory and the aerodynamic characteristics of various airfoil sections (NACA profiles)


The complete text available via the NASA Technical Report Server: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930090976_1993090976.pdf


Report No. 824
Summary of Airfoil Data, 1945
by: Ira H. Abbott, Albert E. von Doenhoff & Louis S. Stivers, Jr.


Also see: University of Illinois - Urbana Champaign - Airfoil Coordinates Database 

USAF Stability & Control DATCOM (Data Compendium)

For those who haven't come across this colossal project, here's a quick intro from its wiki page:

The United States Air Force Stability and Control DATCOM is a collection, correlation, codification, and recording of best knowledge, opinion, and judgment in the area of aerodynamic stability and control prediction methods. It presents substantiated techniques for use (1) early in the design or concept study phase, (2) to evaluate changes resulting from proposed engineering fixes, and (3) as a training on crosstraining aid. It bridges the gap between theory and practice by including a combination of pertinent discussion and proven practical methods. For any given configuration and flight condition, a complete set of stability and control derivatives can be determined without resort to outside information.

A spectrum of methods is presented, ranging from very simple and easily applied techniques to quite accurate and thorough procedures. Comparatively simple methods are presented in complete form, while the more complex methods are often handled by reference to separate treatments. Tables which compare calculated results with test data provide indications of method accuracy. Extensive references to related material are also included. 

The report was compiled from September 1975 to September 1977 by the McDonnell Douglas Corporation in conjunction with the engineers at the Flight Dynamics Laboratory at Wright-Patterson Air Force Base.

Source: http://en.wikipedia.org/wiki/USAF_Stability_and_Control_DATCOM


Ok, with that of the way, here's the entire (1978 revision) declassified PDF document (3134 pages, 113 MB):

http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADB072483

I can safely say that this report was a life saver during stability and control analysis projects and preliminary aircraft design. It also helps that it's easy to use with a detailed table of contents that almost always gets what you what you need.

My stability and control textbook from college extensively implemented DATCOM methods. Here's a preview:



The DATCOM report also gave way to a computer program (USAF Digital DATCOM) which allowed users to analyse various aircraft configurations based on geometry and flight condition inputs.

Intro tutorial we used at college:

Direct link to file: http://openae.org/files/resources/digital_datcom/DATCOM_Tutorial_I.pdf



The Digital DATCOM project has seen 3rd party updates and innovations over the years, with the inclusion of 3D model viewing, MATLAB/Simulink integration etc. To get a better idea: http://en.wikipedia.org/wiki/USAF_Digital_DATCOM#Current_Development

Conflict Resolution: Newton, Bernoulli and 'Lift'

A professor of mine from university put together a superb essay for The Physics Teacher clarifying the concept of aerodynamic lift and how it can be best described by either Newton or Bernoulli's laws. Although this targets educators, undergrad engineering/physics students would probably appreciate the accessibility of this essay.


-k

Equation 16.42 - Raymer 4th Edition

I went through Raymer and a couple of other texts (Stengel, Etkin, etc.) and I it's my understanding that the negative term in eqn 16.42 represents 'propeller fin effect' (Etkin eqn.3.9,8) and is destabilizing for a conventional tractor config. 

The term in question, dBp/dB, is analogous to d(alpha)p/d(alpha), which is seen is eqn 16.30 (Raymer) which is the upwash derivative if the engine is in front of the wings. Similarly, dBp/dB, is probably the sidewash derivative wrt to the prop. 

For a single engine tractor configuration the vertical tail is considered far aft, so that dBp/dB is equal to one. I got this value from a colleague, so there is no text I can point to. Raymer doesn't define this term anywhere. 

I'd appreciate  constructive feedback.

-k

Control Systems Basics

A friend pointed me to North Dakota State University's (NDSU) site as a reference for Control Systems fundamentals. 

The course is available for download in .pdf form complete with lecture notes, worked out examples and diagrams.

http://www.ece.ndsu.nodak.edu/~glower/ee461/Lecture_Fa07/

-k

Kalman Filtering

One of the more interesting control systems topics,


"The Kalman filter has two distinct phases: Predict and Update. The predict phase uses the state estimate from the previous timestep to produce an estimate of the state at the current timestep. In the update phase, measurement information at the current timestep is used to refine this prediction to arrive at a new, (hopefully) more accurate state estimate, again for the current timestep."


Basics --> http://www.cs.unc.edu/~welch/media/pdf/maybeck_ch1.pdf


More --> http://en.wikipedia.org/wiki/Kalman_filter


http://www.elo.utfsm.cl/~ipd481/Papers%20varios/kalman1960.pdf


http://www.cs.unc.edu/~welch/media/pdf/kalman_intro.pdf

DATCOM wing-body analysis

It appears DATCOM is using a wing-body analysis method regardless of the aspect ratio.