In this post I am trying to simplify the understanding and use of AVL especially for those who are using AVL for the first time in life.
You can download the program, sample files, user guide from : http://web.mit.edu/drela/Public/web/avl/
To ease up and tidy the use, I unzipped the avl3.32.tgz and avl332.zip into a same folder in my C drive.
For a simple wing surface, atleast two sections in the wing surface of the avl file are required to identify the start and end co-ordinates of the wing geometry in x, y and z co-ordinate system.
The first section of the Surface (let it be wing / tail) shows the origin values of the geometry. The second section, for a simple design, gives the final geometry co-ordinates.
The two sections also has Chord values and so the values of root chord and tip chord for a tapered wing can be made.
Ainc is the angle of inclination. Some software such as AVLEditor uses ANGLE to identify this. Using AINC. wing tip washout can be made, to change the wing performance at different angle of attacks.
RUNNING DESIGN FILE IN AVL PROGRAM
1. Start the AVL Program from the folder created in the beginning.
2. Type: LOAD [space] Name of the file.avl
eg. load sampleXX.avl
If file is saved at different location from AVL Program then :
LOAD [space] Path of the file\Name of the file.avl
eg. Program is in C: Drive and file in E:
If successful, the program would display as shown in the pic below.
3. Type: OPER to open operating-point run cases.
4. Type: G to open geometric plot of the design.
Follow the geometric plot menu options to view the design. Once complete, hit Return/Enter on AVL command screen to come back to OPER cases menu for further analysis.
5. Type M to enter or edit parameters such as mach no., mass, g , velocity etc.
6. Type: A A Value to enter or edit angle of attack for the geometry.
eg: a a 2.0 or a a 3.7
7. After making any change in either the parameters, AoA or other values - type : X to eXecute the calculations
8. To obtain Trefftz Plot (after execution always) type: T