- #1
Ryoko
- 114
- 5
This is a section from the Pan Air user's guide (Pan Air is a aerodynamic panel-method flow solver).
I'm confused by the symmetry and anti-symmetry. The first one is easy enough: mirror about the XZ plane (Yimage = -Y, Ximage = X, Zimage = Z). The third one is no symmetry applied. Also easy. But the ones describing the antisymmetry have me stumped because they didn't provide any samples of how they define antisymmetry. For example, the last one is antisymmetry about xz with the full model entered. Does this mean that:
Yimage = -Y, Ximage = -X, Zimage = Z
or does it mean:
Yimage = -Y, Ximage = X, Zimage = -Z?
Or maybe it means something else entirely. Thoughts?
To define the planes of flow symmetry or antisymmetry, enter one of the blocks of data
defined below.
Input Data for Flow Symmetry
$SYMMETRIC FLOW ABOUT XZ PLANE
=XZPLN XYPLN
1.0 0.0
! Inputs half configuration
$SYMMETRIC FLOW ABOUT XZ AND XY PLANES
1.0 1.0
! Inputs quarter configuration
$SYM - UNSYMMETRIC FLOW (DEFAULT VALUE)
0.0 0.0
! Inputs full configuration
$SYM - ANTISYMMETRIC FLOW ABOUT XZ PLANE AND SYMMETRIC FLOW ABOUT XY PLANE
1.0 -1.0
! Inputs half configuration
$SYM - ANTISYMMETRIC FLOW ABOUT XZ PLANE
-1.0 0.0
! Inputs full configuration above or below XZ plane
Most configuration and flow analyses have one plane of symmetry. For this type of
problem, you only need to define half the configuration. Onset flow is defined with a zero
angle of yaw. This approach represents a considerable savings over an analysis of the
complete configuration. A summary of the planes of symmetry and the recommended
placement of the configuration are given in figure 5-5.
I'm confused by the symmetry and anti-symmetry. The first one is easy enough: mirror about the XZ plane (Yimage = -Y, Ximage = X, Zimage = Z). The third one is no symmetry applied. Also easy. But the ones describing the antisymmetry have me stumped because they didn't provide any samples of how they define antisymmetry. For example, the last one is antisymmetry about xz with the full model entered. Does this mean that:
Yimage = -Y, Ximage = -X, Zimage = Z
or does it mean:
Yimage = -Y, Ximage = X, Zimage = -Z?
Or maybe it means something else entirely. Thoughts?