AIM Attributes

The following list of attributes drives the AVL geometric definition. Each FaceBody which relates to AVL Sections will be marked up in an appropriate manner to drive the input file construction. Many attributes are required and those that are optional are marked so in the description:

• capsReferenceArea This attribute may exist on any Body. Its value will be used as the SREF entry in the AVL input.
• capsReferenceChord This attribute may exist on any Body. Its value will be used as the CREF entry in the AVL input.
• capsReferenceSpan This attribute may exist on any Body. Its value will be used as the BREF entry in the AVL input.
• capsReferenceX [Optional: Default 0.0] This attribute may exist on any Body. Its value will be used as the Xref entry in the AVL input.
• capsReferenceY [Optional: Default 0.0] This attribute may exist on any Body. Its value will be used as the Yref entry in the AVL input.
• capsReferenceZ [Optional: Default 0.0] This attribute may exist on any Body. Its value will be used as the Zref entry in the AVL input.
• capsGroup This string attribute labels the FaceBody as to which AVL Surface the section is assigned. This should be something like: Main_Wing, Horizontal_Tail, etc. This informs the AVL AIM to collect all FaceBodies that match this attribute into a single AVL Surface.
  Note: If a capsGroup contains only one section then the section is treated as a slender body, and only the numChord and spaceChord in the "AVL_Surface" (Vortex Lattice Surface) input will be used.
• vlmControl"Name" This string attribute attaches a control surface to the FaceBody. The hinge location is defined as the double value between 0 or 1.0. The range as percentage from 0 to 100 will also work. The name of the control surface is the string information after vlmControl (or vlmControl_). For Example, to define a control surface named Aileron the following are identical (attribute vlmControlAileron 0.8 or attribute vlmControl_Aileron 80) . Multiple vlmControl attributes, with different names, can be defined on a single FaceBody.
  
  By default control surfaces with percentages less than 0.5 (< 50%) are leading edge slats (with the control surface is between leading edge and hinge location), while values greater than or equal to 0.5 (>= 50%) are considered trailing edge flaps (with the control surface between the hinge location and trailing edge). This behavior may be overwritten with the "AVL_Control" (see AIM Inputs) input keyword "leOrTe" (see Vortex Lattice Control Surface for additional details).
  
  • For leOrTe = 0, the control surface is always between the leading edge and the hinge line.
  • For leOrTe = 1, the control surface is always between the trailing edge and the hinge line.
• vlmNumSpan This attribute may be set on any given airfoil cross-section to overwrite the number of spanwise horseshoe vortices placed on the surface (globally set - see keyword "numSpanPerSection" and "numSpanTotal" in Vortex Lattice Surface ) between two sections. Note, that the AIM internally sorts the sections in ascending y (or z) order, so care should be taken to select the correct section for the desired intent.

Note: The attribute avlNumSpan has been deprecated in favor of vlmNumSpan

• vlmSspace This attribute may be set on any given airfoil cross-section in the range [-1 .. 1] specify the spanwise distribution function.
• vlmNumChord This attribute may be set on any given airfoil cross-section to overwrite the number of chordwise horseshoe vortices placed on the surface (globally set - see keyword "numChord" in Vortex Lattice Surface ).
  vlmNumChord must be the same if set on multiple sections of a surface.
• vlmCspace This attribute may be set on any given airfoil cross-section in the range [-1 .. 1] specify the chordwise distribution function.
  vlmCspace must be the same if set on multiple sections of a surface.
• vlmCDCL The CD-CL polar is based on a simple interpolation. Must be a list of 6 [CL1, CD1, CL2, CD2, CL3, CD3] entries. See AVL documentation for more details.