def make_span_break(cs_ID, LE_TE, ib_ob, span_frac, chord_cut, Airfoil,
dihedral_ob, sweep_ob_QC, sweep_ob_LE, twist, local_chord,
x_offset, dih_offset):
""" This gathers information related to a span break into one Data() object.
A span break is the spanwise location of a discontinuity in the discretization
of the panels. These can be caused by segments and by the inboard and outboard
edges of a control surface. The inboard and outboard sides of a span break can
have different chords due to cuts made by control surfaces. Ultimately, the
attributes of the span_breaks of the wing will provide the discretization function
generate_wing_vortex_distribution() with the necessary values to make VLM panels
as well as reshape those panels to make the control surface cuts dipicted below.
A diagram is given below:
nominal local chord
fuselage inboard LE | | . outboard LE
<--- | | .
| | .
| | . <-- cut from a slat
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | . <-- cut from a non-slat control surface with a different chord
cut from a non-slat control surface | | . fraction than the control surface on the inboard side
--> . | .
. | .
inboard TE . | . outboard TE
|_______________________|
|
there is 0 spanwise
distance between inboard
and outboard sides
Outputs:
span_break
Properties Used:
N/A
"""
span_break = Data()
span_break.cs_IDs = np.array([[-1,-1], # [[inboard LE cs, outboard LE cs],
[-1,-1]]) # [inboard TE cs, outboard TE cs]]
span_break.cs_IDs[LE_TE,ib_ob] = cs_ID
span_break.span_fraction = span_frac
# The following 'cut' attributes are in terms of the local total chord and represent positions.
# (an aileron with chord fraction 0.2 would have a cut value of 0.8)
# For inboard_cut, -1 takes value of previous outboard cut value in a later function
# For outboard_cut, -1 takes value of next inboard cut value.
# If no break directly touching this one, cut becomes 0 (LE) or 1 (TE).
span_break.cuts = np.array([[0.,0.], # [[inboard LE cut, outboard LE cut],
[1.,1.]]) # [inboard TE cut, outboard TE cut]]
span_break.cuts[LE_TE,ib_ob] = chord_cut
span_break.Airfoil = Airfoil
span_break.dihedral_outboard = dihedral_ob
span_break.sweep_outboard_QC = sweep_ob_QC
span_break.sweep_outboard_LE = sweep_ob_LE
span_break.twist = twist
span_break.local_chord = local_chord #this is the local chord BEFORE cuts are made
span_break.x_offset = x_offset
span_break.dih_offset = dih_offset #dih_offset is the y or z accumulated offset from dihedral
span_break.tag = make_span_break_tag(span_break)
return span_break
