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• Any such redistributions must be done under the terms of the GPL, else the permission is withdrawn.

Announcements

• A Slovenian translation of this webpage has been created by Mary Orban.

Software

Latest Versions

• avl3.40b.tgz (606752 bytes)
  AVL 3.40b for Unix and Win32. Gzipped directory tar image.
  All source code, User Guide, sample AVL session inputs.
  Requires Fortran, C compilers, windowing support.
• avl (1853240 bytes)
  AVL 3.40b executable for Intel x86_64. Requires xQuartz for graphics.
• avl (1685504 bytes)
  AVL 3.40b executable for ARM MacOS. Requires xQuartz for graphics.
• avl (1054104 bytes)
  AVL 3.40b executable for Linux 64. Requires libX11 libraries for graphics.
• avl.exe (1674868 bytes)
  AVL 3.40b executable for Windows.
• avl3.36.tgz (606752 bytes)
• avl3.36.exe.zip (509063 bytes)
  AVL 3.36 executable for Windows.
• avl3.35.tgz (1041053 bytes)
• avl335.zip (505104 bytes)
  AVL 3.35 executable for Windows.
• avl335_MacOSX.zip (95232 bytes)
  AVL 3.35 executable for Mac OSX. Requires Quartz library to be present on system.
• avl3.32.tgz (496506 bytes)
• 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
• AVL_User_Primer.pdf
  User Guide in Latex PDF (courtesy of Wendy Yang of Berkeley)
• 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

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)

10 Feb 14
- Added second-order righthand sides to the VL system, proportional to both the unit translation+rotation velocities, and to control deflections. This improves convergence to the trim condition. It also gives the correct eigenmode solutions even for large trim control deflections. Only the very slow eigenmodes, especially the phugoid, will be affected by this change. A few other minor features were added since 3.32. See version_notes.txt.
- AVL 3.35 for Linux.

23 Feb 14
- Windows executable for AVL 3.35 (courtesy of Harold Youngren)

29 Jan 15
- MacOSX executable for AVL 3.35 (courtesy of Harold Youngren)

23 Feb 17
- Made a few fixes and tweaks. See version_notes.txt file.
- Windows executable for AVL 3.36 (courtesy of Harold Youngren)

18 Apr 22
- AVL 3.40b , courtesy of Steven Allmaras.
- Has wider variety of output options -- see version_notes.txt
- Switched to LAPACK matrix solver for faster execution