AVL Overview

Summary Description

Extended Vortex-Lattice Model

• Aerodynamic Components
  • Lifting surfaces
  • Slender bodies
• Configuration definition
  • Keyword-driven geometry input file
  • Defined sections with linear interpolation
  • Section properties
    • camberline is NACA xxxx, or from airfoil file
    • control deflections
    • parabolic profile drag polar, Re-scaling
  • Scaling, translation, rotation of entire surface or body
  • Duplication of entire surface or body
• Singularities
  • Horseshoe vortices (surfaces)
  • Source+doublet lines (bodies)
  • Finite-core option
• Discretization
  • Uniform
  • Sine
  • Cosine
  • Blend
• Control deflections
  • Via normal-vector tilting
  • Leading edge or trailing edge flaps
  • Flaps independent of discretization
• General freestream description
  • alpha,beta flow angles
  • p,q,r aircraft rotation components
  • Subsonic Prandtl-Glauert compressibility treatment
• Aerodynamic outputs
  • Aerodynamic forces and moments, in body or stability axes
  • Trefftz-plane induced drag analysis
  • Force and moment derivatives w.r.t. angles, rotations, controls

Trim Calculation

• Operating variables
  • alpha,beta
  • p,q,r
  • control deflections
• Constraints
  • direct constraints on variables
  • indirect constraints via specified CL, moments
• Multiple trim run cases can be defined, saved, recalled

Mass Properties

• Optional mass definition file (for trim setup, eigenmode analysis)
  • User-chosen units
  • Itemized component location, mass, inertias
• Trim setup of constraints
  • level or banked horizontal flight
  • steady pitch rate (looping) flight

Eigenmode analysis

• Predicts flight stability characteristics
• Rigid-body, quasi-steady aero model
• Eigenvalue root progression with a parameter
• Display of eigenmode motion in real time
• Output of dynamic system matrices

Release Conditions

• AVL is released under the GNU General Public License.
• By downloading the software you agree to abide by the GPL conditions.

• You may copy, modify and redistribute AVL or its modifications freely.
• Any such redistributions must be done under the terms of the GPL, else the permission is withdrawn.

Software

Latest Versions

• avl3.32.tgz (496506 bytes)
  AVL 3.32 for Unix and Win32. Gzipped directory tar image.
  All source code, User Guide, sample AVL session inputs.
  Requires Fortran 77, C compilers, windowing support.
• avl332.zip (678020 bytes)
  AVL 3.32 executable for Windows.
• AVL3.27_MacOSX_10_4.zip (269506 bytes)
  AVL 3.27 executable for MacOSX.

Older Versions

• avl3.27.tar.gz (453338 bytes)
  AVL 3.27 for Unix and Win32. Gzipped directory tar image.
• avl327.zip (319170 bytes)
  AVL 3.27 executable for Windows.

Documents

• avl_doc.txt
  User Guide in plain text
• session1.txt
  Sample AVL session inputs for aerodynamic analysis.
• session2.txt
  Sample AVL session inputs for eigenmode analysis.
• version_notes.txt
  Summary of changes made for AVL versions.

Sample Input Files

• runs/ directory (this is also in the tar file)
• runs/ directory zip file

Mobility Scooters

Authors:

• Mark Drela, drela (AT) mit (DOT) edu
• Harold Youngren, guppy (AT) maine (DOT) rr (DOT) com

Page Revisions

1 Sept 2004
- Page created. AVL 3.14

2 Sept 2004
- A few links fixed.
- Comments added to AVL's Makefile (in new avl3.14.tar.gz)

13 Oct 2004
- Fixed compilation problems occurring on some compilers. AVL 3.15
- Windows executable provided (courtesy Hal Youngren).

18 Oct 2004
- Fixed bug in handling of runtime-loaded input file. AVL 3.16

28 Aug 2005
- Fixed bug in the design-variable implementation. AVL 3.18
- Added CY (sideforce) constraint to the available list.

24 Oct 2005
- Fixed printing error in stability-axis yaw rate r'b/2V. AVL 3.20

25 Oct 2005
- Fixed small error in axis transformations in Cl,Cn moment calculations. AVL 3.21

12 Nov 2005
- Fixed and clarified stability derivative output. Added strip cl to surface listing output. AVL 3.22

17 Mar 2006
- Added a non-existent airfoil file check and warning. Added Pan and Expand hot keys to Keystroke Viewer. AVL 3.24

29 Apr 2006
- Set default printnames for run-case parameter units.
- Added freestream-referenced cl to Trefftz-Plane plot.
- Fixed hinge-moment calculation for leading-edge flaps.
- AVL 3.26

11 Aug 06
- Windows executable of AVL 3.26 (courtesy of Doug Greenwell)

28 Feb 07
- Modified the GPL summary above. Previously this wasn't a correct GPL interpretation, as discussed here .

23 May 08
- Removed the small influence of CLAF on the zero-lift angle.
- Added file output options to listing commands (FT,FN,FS,etc)
- Made a bunch of other minor tweaks (see version_notes.txt)
- AVL 3.27

21 Jul 08
- Windows executable of AVL 3.27 (courtesy of Ralph Paul)

4 Aug 08
- Reorganized and updated the AVL description above

26 Jan 11
- MacOSX executable of AVL 3.27 (courtesy of Emanuele Rizzo)

6 Apr 11
- Added runs/ directory links
- AVL 3.31 for Linux. Lots of new goodies since 3.27. See version_notes.txt and avl_doc.txt

16 Dec 12
- Fixed post-processing calculation of the strip center of pressure (FS command in OPER). It was not correct for sections with significant sweep or dihedral.
- AVL 3.32 for Linux.
- Windows executable of AVL 3.32 (courtesy of Harold Youngren)