Structure for the Vortex Lattice Surface tuple = ("Name of Surface", "Value"). "Name of surface defines the name of the surface in which the data should be applied.
The "Value" can either be a JSON String dictionary (see Section JSON String Dictionary) or a single string keyword string (see Section Single Value String).
JSON String Dictionary
If "Value" is a JSON string dictionary (eg. "Value" = {"numChord": 5, "spaceChord": 1.0, "numSpan": 10, "spaceSpan": 0.5}) the following keywords ( = default values) may be used:
-
groupName = "(no default)"
Single or list of capsGroup names used to define the surface (e.g. "Name1" or ["Name1","Name2",...]. If no groupName variable is provided an attempted will be made to use the tuple name instead;
-
noKeyword = "(no default)"
"No" type. Options: NOWAKE, NOALBE, NOLOAD.
-
numChord = 10
The number of chordwise horseshoe vortices placed on the surface.
-
spaceChord = 1.0
The chordwise vortex spacing parameter.
Note: The local spanwise spacing may be overridden using the vlmSspace BODY attribute on a section.
-
numSpanTotal = 0
Total number of spanwise horseshoe vortices placed on the surface. The vorticies are 'evenly' distributed across sections to minimize jumps in spacings. numpSpanPerSection must be zero if this is set.
Note: The local spanwise count may be overridden using the vlmNumSpan BODY attribute on a section.
-
numSpanPerSection = 0
The number of spanwise horseshoe vortices placed on each section the surface. The total number of spanwise vorticies are (numSection-1)*numSpanPerSection. The vorticies are 'evenly' distributed across sections to minimize jumps in spacings. numSpanTotal must be zero if this is set.
Note: The local spanwise count may be overridden using the vlmNumSpan BODY attribute on a section.
-
yMirror = False
Mirror surface about the y-direction.
-
component = 0
A positive number allows multiple input SURFACEs to be grouped together into a composite virtual surface. Application examples are:
- A wing component made up of a wing SURFACE and a winglet SURFACE
- A T-tail component made up of horizontal and vertical tail SURFACEs.
-
CLaf = 0.0
This scales the effective dcl/da of the section airfoil as follows:
dcl/da = 2 pi ( 1 + CLaf t/c )
where t/c is the airfoil's thickness/chord ratio.
Single Value String
If "Value" is a single string the following options maybe used:
