# RCAIDE/Framework/External_Interfaces/OpenVSP/vsp_fuselage.py
# Created: Jun 2018, T. St Francis
# Modified: Aug 2018, T. St Francis
# Jan 2020, T. MacDonald
# Jul 2020, E. Botero
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# RCAIDE imports
import RCAIDE
from RCAIDE.Framework.Core import Units, Data
import numpy as np
try:
import vsp as vsp
except ImportError:
try:
import openvsp as vsp
except ImportError:
# This allows RCAIDE to build without OpenVSP
pass
# ----------------------------------------------------------------------------------------------------------------------
# vsp read fuselage
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def read_vsp_fuselage(fuselage_id,fux_idx,sym_flag, units_type='SI', fineness=True, use_scaling=True):
"""This reads an OpenVSP fuselage geometry and writes it to a RCAIDE fuselage format.
Assumptions:
1. OpenVSP fuselage is "conventionally shaped" (generally narrow at nose and tail, wider in center).
2. Fuselage is designed in VSP as it appears in real life. That is, the VSP model does not rely on
superficial elements such as canopies, stacks, or additional fuselages to cover up internal lofting oddities.
3. This program will NOT account for multiple geometries comprising the fuselage. For example: a wingbox mounted beneath
is a separate geometry and will NOT be processed.
4. Fuselage origin is located at nose. VSP file origin can be located anywhere, preferably at the forward tip
of the vehicle or in front (to make all X-coordinates of vehicle positive).
5. Written for OpenVSP 3.21.1
Source:
N/A
Inputs:
0. Pre-loaded VSP vehicle in memory, via import_vsp_vehicle.
1. VSP 10-digit geom ID for fuselage.
2. Units_type set to 'SI' (default) or 'Imperial'.
3. Boolean for whether or not to compute fuselage finenesses (default = True).
4. Boolean for whether or not to use the scaling from OpenVSP (default = True).
Outputs:
Writes RCAIDE fuselage, with these geometries: (all defaults are SI, but user may specify Imperial)
Fuselages.Fuselage.
origin [m] in all three dimensions
width [m]
lengths.
total [m]
nose [m]
tail [m]
heights.
maximum [m]
at_quarter_length [m]
at_three_quarters_length [m]
effective_diameter [m]
fineness.nose [-] ratio of nose section length to fuselage effective diameter
fineness.tail [-] ratio of tail section length to fuselage effective diameter
areas.wetted [m^2]
tag <string>
segment[]. (segments are in ordered container and callable by number)
vsp.shape [point,circle,round_rect,general_fuse,fuse_file]
vsp.xsec_id <10 digit string>
percent_x_location
percent_z_location
height
width
length
effective_diameter
tag
vsp.xsec_num <integer of fuselage segment quantity>
vsp.xsec_surf_id <10 digit string>
Properties Used:
N/A
"""
fuselage = RCAIDE.Library.Components.Fuselages.Fuselage()
if units_type == 'SI':
units_factor = Units.meter * 1.
elif units_type == 'imperial':
units_factor = Units.foot * 1.
elif units_type == 'inches':
units_factor = Units.inch * 1.
if vsp.GetGeomName(fuselage_id):
fuselage.tag = vsp.GetGeomName(fuselage_id) + '_' + str(fux_idx+1)
else:
fuselage.tag = 'FuselageGeom' + '_' + str(fux_idx+1)
if use_scaling:
scaling = vsp.GetParmVal(fuselage_id, 'Scale', 'XForm')
else:
scaling = 1.
units_factor = units_factor*scaling
fuselage.origin[0][0] = vsp.GetParmVal(fuselage_id, 'X_Location', 'XForm') * units_factor
fuselage.origin[0][1] = vsp.GetParmVal(fuselage_id, 'Y_Location', 'XForm') * units_factor*sym_flag
fuselage.origin[0][2] = vsp.GetParmVal(fuselage_id, 'Z_Location', 'XForm') * units_factor
fuselage.lengths.total = vsp.GetParmVal(fuselage_id, 'Length', 'Design') * units_factor
fuselage.vsp_data.xsec_surf_id = vsp.GetXSecSurf(fuselage_id, 0) # There is only one XSecSurf in geom.
fuselage.vsp_data.xsec_num = vsp.GetNumXSec(fuselage.vsp_data.xsec_surf_id) # Number of xsecs in fuselage.
x_locs = []
heights = []
widths = []
eff_diams = []
lengths = []
# -----------------
# Fuselage segments
# -----------------
for ii in range(0, fuselage.vsp_data.xsec_num):
# Create the segment
x_sec = vsp.GetXSec(fuselage.vsp_data.xsec_surf_id, ii) # VSP XSec ID.
vsp_section_index = vsp.GetXSecShape(vsp.GetXSec(fuselage.vsp_data.xsec_surf_id, ii))
if vsp_section_index == 1:
segment = RCAIDE.Library.Components.Fuselages.Segments.Circle_Segment()
elif vsp_section_index == 2:
segment = RCAIDE.Library.Components.Fuselages.Segments.Ellipse_Segment()
elif vsp_section_index == 3:
segment = RCAIDE.Library.Components.Fuselages.Segments.Super_Ellipse_Segment()
elif vsp_section_index == 4:
segment = RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment()
else:
segment = RCAIDE.Library.Components.Fuselages.Segments.Segment()
segment = RCAIDE.Library.Components.Fuselages.Segments.Segment()
segment.vsp_data.xsec_id = x_sec
segment.tag = 'segment_' + str(ii)
# Pull out Parms that will be needed
X_Loc_P = vsp.GetXSecParm(x_sec, 'XLocPercent')
Z_Loc_P = vsp.GetXSecParm(x_sec, 'ZLocPercent')
segment.percent_x_location = vsp.GetParmVal(X_Loc_P) # Along fuselage length.
segment.percent_z_location = vsp.GetParmVal(Z_Loc_P ) # Vertical deviation of fuselage center.
segment.height = vsp.GetXSecHeight(segment.vsp_data.xsec_id) * units_factor
segment.width = vsp.GetXSecWidth(segment.vsp_data.xsec_id) * units_factor
segment.effective_diameter = (segment.height+segment.width)/2.
x_locs.append(segment.percent_x_location) # Save into arrays for later computation.
heights.append(segment.height)
widths.append(segment.width)
eff_diams.append(segment.effective_diameter)
if ii != (fuselage.vsp_data.xsec_num-1): # Segment length: stored as length since previous segment. (last segment will have length 0.0.)
next_xsec = vsp.GetXSec(fuselage.vsp_data.xsec_surf_id, ii+1)
X_Loc_P_p = vsp.GetXSecParm(next_xsec, 'XLocPercent')
percent_x_loc_p1 = vsp.GetParmVal(X_Loc_P_p)
segment.length = fuselage.lengths.total*(percent_x_loc_p1 - segment.percent_x_location) * units_factor
else:
segment.length = 0.0
lengths.append(segment.length)
shape = vsp.GetXSecShape(segment.vsp_data.xsec_id)
shape_dict = {0:'point',1:'circle',2:'ellipse',3:'super ellipse',4:'rounded rectangle',5:'general fuse',6:'fuse file'}
segment.vsp_data.shape = shape_dict[shape]
fuselage.segments.append(segment)
fuselage.heights.at_quarter_length = get_fuselage_height(fuselage, .25) # Calls get_fuselage_height function (below).
fuselage.heights.at_three_quarters_length = get_fuselage_height(fuselage, .75)
fuselage.heights.at_wing_root_quarter_chord = get_fuselage_height(fuselage, .4)
fuselage.heights.maximum = max(heights) # Max segment height.
fuselage.width = max(widths) # Max segment width.
fuselage.effective_diameter = max(eff_diams) # Max segment effective diam.
fuselage.areas.front_projected = np.pi*((fuselage.effective_diameter)/2)**2
eff_diam_gradients_fwd = np.array(eff_diams[1:]) - np.array(eff_diams[:-1]) # Compute gradients of segment effective diameters.
eff_diam_gradients_fwd = np.multiply(eff_diam_gradients_fwd, lengths[:-1])
fuselage = compute_fuselage_fineness(fuselage, x_locs, eff_diams, eff_diam_gradients_fwd)
return fuselage
# ----------------------------------------------------------------------------------------------------------------------
# Write VSP Fuselage
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def write_vsp_fuselage(fuselage,area_tags, main_wing, fuel_tank_set_ind, OML_set_ind):
"""This writes a fuselage into OpenVSP format.
Assumptions:
None
Source:
N/A
Inputs:
fuselage
width [m]
lengths.total [m]
heights.
maximum [m]
at_quarter_length [m]
at_wing_root_quarter_chord [m]
at_three_quarters_length [m]
effective_diameter [m]
fineness.nose [-] ratio of nose section length to fuselage width
fineness.tail [-] ratio of tail section length to fuselage width
tag <string>
OpenVSP_values. (optional)
nose.top.angle [degrees]
nose.top.strength [-] this determines how much the specified angle influences that shape
nose.side.angle [degrees]
nose.side.strength [-]
nose.TB_Sym <boolean> determines if top angle is mirrored on bottom
nose.z_pos [-] z position of the nose as a percentage of fuselage length (.1 is 10%)
tail.top.angle [degrees]
tail.top.strength [-]
tail.z_pos (optional, 0.02 default) [-] z position of the tail as a percentage of fuselage length (.1 is 10%)
Segments. (optional)
width [m]
height [m]
percent_x_location [-] .1 is 10% length
percent_z_location [-] .1 is 10% length
area_tags <dict> used to keep track of all tags needed in wetted area computation
main_wing.origin [m]
main_wing.chords.root [m]
fuel_tank_set_index <int> OpenVSP object set containing the fuel tanks
Outputs:
Operates on the active OpenVSP model, no direct output
Properties Used:
N/A
"""
segment_list = list(fuselage.segments.keys())
num_segs = len(segment_list)
length = fuselage.lengths.total
fuse_x = fuselage.origin[0][0]
fuse_y = fuselage.origin[0][1]
fuse_z = fuselage.origin[0][2]
fuse_x_rotation = fuselage.x_rotation
fuse_y_rotation = fuselage.y_rotation
fuse_z_rotation = fuselage.z_rotation
if num_segs==0: # RCAIDE default fuselage shaping
width = fuselage.width
hmax = fuselage.heights.maximum
height1 = fuselage.heights.at_quarter_length
height2 = fuselage.heights.at_wing_root_quarter_chord
height3 = fuselage.heights.at_three_quarters_length
effdia = fuselage.effective_diameter
n_fine = fuselage.fineness.nose
t_fine = fuselage.fineness.tail
try:
if main_wing != None:
w_origin = main_wing.origin
w_c_4 = main_wing.chords.root/4.
else:
w_origin = 0.5*length
w_c_4 = 0.5*length
except AttributeError:
raise AttributeError('Main wing not detected. Fuselage must have specified sections in this configuration.')
# Figure out the location x location of each section, 3 sections, end of nose, wing origin, and start of tail
x1 = n_fine*width/length
x2 = (w_origin[0][0]+w_c_4)/length
x3 = 1-t_fine*width/length
end_ind = 4
else: # Fuselage shaping based on sections
widths = []
heights = []
radii = []
x_poses = []
z_poses = []
segs = fuselage.segments
for seg in segs:
widths.append(seg.width)
heights.append(seg.height)
radii.append(seg.radius)
x_poses.append(seg.percent_x_location)
z_poses.append(seg.percent_z_location)
end_ind = num_segs-1
fuse_id = vsp.AddGeom("FUSELAGE")
vsp.SetGeomName(fuse_id, fuselage.tag)
area_tags[fuselage.tag] = ['fuselages',fuselage.tag]
tail_z_pos = 0.02 # default value
# set fuselage relative location and rotation
vsp.SetParmVal( fuse_id,'X_Rel_Rotation','XForm',fuse_x_rotation)
vsp.SetParmVal( fuse_id,'Y_Rel_Rotation','XForm',fuse_y_rotation)
vsp.SetParmVal( fuse_id,'Z_Rel_Rotation','XForm',fuse_z_rotation)
vsp.SetParmVal( fuse_id,'X_Rel_Location','XForm',fuse_x)
vsp.SetParmVal( fuse_id,'Y_Rel_Location','XForm',fuse_y)
vsp.SetParmVal( fuse_id,'Z_Rel_Location','XForm',fuse_z)
if 'OpenVSP_values' in fuselage:
vals = fuselage.OpenVSP_values
# for wave drag testing
fuselage.OpenVSP_ID = fuse_id
# Nose
vsp.SetParmVal(fuse_id,"TopLAngle","XSec_0",vals.nose.top.angle)
vsp.SetParmVal(fuse_id,"TopLStrength","XSec_0",vals.nose.top.strength)
vsp.SetParmVal(fuse_id,"RightLAngle","XSec_0",vals.nose.side.angle)
vsp.SetParmVal(fuse_id,"RightLStrength","XSec_0",vals.nose.side.strength)
vsp.SetParmVal(fuse_id,"TBSym","XSec_0",vals.nose.TB_Sym)
vsp.SetParmVal(fuse_id,"ZLocPercent","XSec_0",vals.nose.z_pos)
if not vals.nose.TB_Sym:
vsp.SetParmVal(fuse_id,"BottomLAngle","XSec_0",vals.nose.bottom.angle)
vsp.SetParmVal(fuse_id,"BottomLStrength","XSec_0",vals.nose.bottom.strength)
if 'z_pos' in vals.tail:
tail_z_pos = vals.tail.z_pos
else:
pass # use above default
if num_segs == 0:
vsp.SetParmVal(fuse_id,"Length","Design",length)
vsp.SetParmVal(fuse_id,"Diameter","Design",width)
vsp.SetParmVal(fuse_id,"XLocPercent","XSec_1",x1)
vsp.SetParmVal(fuse_id,"XLocPercent","XSec_2",x2)
vsp.SetParmVal(fuse_id,"XLocPercent","XSec_3",x3)
vsp.SetParmVal(fuse_id,"ZLocPercent","XSec_4",tail_z_pos)
vsp.SetParmVal(fuse_id, "Ellipse_Width", "XSecCurve_1", width)
vsp.SetParmVal(fuse_id, "Ellipse_Width", "XSecCurve_2", width)
vsp.SetParmVal(fuse_id, "Ellipse_Width", "XSecCurve_3", width)
vsp.SetParmVal(fuse_id, "Ellipse_Height", "XSecCurve_1", height1);
vsp.SetParmVal(fuse_id, "Ellipse_Height", "XSecCurve_2", height2);
vsp.SetParmVal(fuse_id, "Ellipse_Height", "XSecCurve_3", height3);
else:
# OpenVSP vals do not exist:
vals = Data()
vals.nose = Data()
vals.tail = Data()
vals.tail.top = Data()
vals.nose.z_pos = 0.0
vals.tail.top.angle = 0.0
vals.tail.top.strength = 0.0
vsp.SetParmVal(fuse_id,"Length","Design",length)
if num_segs != 5: # reduce to only nose and tail
vsp.CutXSec(fuse_id,1) # remove extra default section
vsp.CutXSec(fuse_id,1) # remove extra default section
vsp.CutXSec(fuse_id,1) # remove extra default section
for i1 in reversed(range(num_segs-2)): # add back the required number of sections
if type(segs[segment_list[i1]]) == RCAIDE.Library.Components.Fuselages.Segments.Circle_Segment:
vsp.InsertXSec(fuse_id, 0, vsp.XS_CIRCLE)
elif type(segs[segment_list[i1]]) == RCAIDE.Library.Components.Fuselages.Segments.Ellipse_Segment:
vsp.InsertXSec(fuse_id, 0, vsp.XS_ELLIPSE)
elif type(segs[segment_list[i1]]) == RCAIDE.Library.Components.Fuselages.Segments.Super_Ellipse_Segment:
vsp.InsertXSec(fuse_id, 0, vsp.XS_SUPER_ELLIPSE)
elif type(segs[segment_list[i1]]) == RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment:
vsp.InsertXSec(fuse_id, 0, vsp.XS_ROUNDED_RECTANGLE)
else:
vsp.InsertXSec(fuse_id, 0, vsp.XS_ELLIPSE)
vsp.Update()
for i2 in range(num_segs-2):
# Bunch sections to allow proper length settings in the next step
# This is necessary because OpenVSP will not move a section past an adjacent section
vsp.SetParmVal(fuse_id, "XLocPercent", "XSec_"+str(i2+1),1e-6*(i2+1))
vsp.Update()
if x_poses[1] < (num_segs-2)*1e-6:
print('Warning: Second fuselage section is too close to the nose. OpenVSP model may not be accurate.')
for i3 in reversed(range(num_segs-2)):
# order is reversed because sections are initially bunched in the front and cannot be extended passed the next
vsp.SetParmVal(fuse_id, "XLocPercent", "XSec_"+str(i3+1),x_poses[i3+1])
vsp.SetParmVal(fuse_id, "ZLocPercent", "XSec_"+str(i3+1),z_poses[i3+1])
if type(segs[segment_list[i3]]) == RCAIDE.Library.Components.Fuselages.Segments.Circle_Segment:
vsp.SetParmVal(fuse_id, "Circle_Diameter", "XSecCurve_"+str(i3+1), widths[i3+1])
elif type(segs[segment_list[i3]]) == RCAIDE.Library.Components.Fuselages.Segments.Ellipse_Segment:
vsp.SetParmVal(fuse_id, "Ellipse_Width", "XSecCurve_"+str(i3+1), widths[i3+1])
vsp.SetParmVal(fuse_id, "Ellipse_Height", "XSecCurve_"+str(i3+1), heights[i3+1])
elif type(segs[segment_list[i3]]) == RCAIDE.Library.Components.Fuselages.Segments.Super_Ellipse_Segment:
vsp.SetParmVal(fuse_id, "Super_Width", "XSecCurve_"+str(i3+1), widths[i3+1])
vsp.SetParmVal(fuse_id, "Super_Height", "XSecCurve_"+str(i3+1), heights[i3+1])
elif type(segs[segment_list[i3]]) == RCAIDE.Library.Components.Fuselages.Segments.Rounded_Rectangle_Segment:
vsp.SetParmVal(fuse_id, "RoundedRect_Width", "XSecCurve_"+str(i3+1), widths[i3+1])
vsp.SetParmVal(fuse_id, "RoundedRect_Height", "XSecCurve_"+str(i3+1), heights[i3+1])
vsp.SetParmVal(fuse_id, "RoundRectXSec_Radius", "XSecCurve_"+str(i3+1), radii[i3+1])
else:
vsp.SetParmVal(fuse_id, "Ellipse_Width", "XSecCurve_"+str(i3+1), widths[i3+1])
vsp.SetParmVal(fuse_id, "Ellipse_Height", "XSecCurve_"+str(i3+1), heights[i3+1])
vsp.Update()
set_section_angles(i3, vals.nose.z_pos, tail_z_pos, x_poses, z_poses, heights, widths,length,end_ind,fuse_id)
vsp.SetParmVal(fuse_id,"TopLAngle","XSec_"+str(0),90)
vsp.SetParmVal(fuse_id,"RightLAngle","XSec_"+str(0),90)
vsp.SetParmVal(fuse_id, "XLocPercent", "XSec_"+str(0),x_poses[0])
vsp.SetParmVal(fuse_id, "ZLocPercent", "XSec_"+str(0),z_poses[0])
vsp.SetParmVal(fuse_id, "XLocPercent", "XSec_"+str(end_ind),x_poses[-1])
vsp.SetParmVal(fuse_id, "ZLocPercent", "XSec_"+str(end_ind),z_poses[-1])
# Tail
if heights[-1] > 0.:
pos = len(heights)-1
vsp.InsertXSec(fuse_id, pos-1, vsp.XS_ELLIPSE)
vsp.Update()
vsp.SetParmVal(fuse_id, "Ellipse_Width", "XSecCurve_"+str(pos), widths[-1])
vsp.SetParmVal(fuse_id, "Ellipse_Height", "XSecCurve_"+str(pos), heights[-1])
vsp.SetParmVal(fuse_id, "XLocPercent", "XSec_"+str(pos),x_poses[-1])
vsp.SetParmVal(fuse_id, "ZLocPercent", "XSec_"+str(pos),z_poses[-1])
xsecsurf = vsp.GetXSecSurf(fuse_id,0)
vsp.ChangeXSecShape(xsecsurf,pos+1,vsp.XS_POINT)
vsp.Update()
vsp.SetParmVal(fuse_id, "XLocPercent", "XSec_"+str(pos+1),x_poses[-1])
vsp.SetParmVal(fuse_id, "ZLocPercent", "XSec_"+str(pos+1),z_poses[-1])
# update strengths to make end flat
vsp.SetParmVal(fuse_id,"TopRStrength","XSec_"+str(pos), 0.)
vsp.SetParmVal(fuse_id,"RightRStrength","XSec_"+str(pos), 0.)
vsp.SetParmVal(fuse_id,"BottomRStrength","XSec_"+str(pos), 0.)
vsp.SetParmVal(fuse_id,"TopLStrength","XSec_"+str(pos+1), 0.)
vsp.SetParmVal(fuse_id,"RightLStrength","XSec_"+str(pos+1), 0.)
else:
vsp.SetParmVal(fuse_id,"TopLAngle","XSec_"+str(end_ind),vals.tail.top.angle)
vsp.SetParmVal(fuse_id,"TopLStrength","XSec_"+str(end_ind),vals.tail.top.strength)
vsp.SetParmVal(fuse_id,"AllSym","XSec_"+str(end_ind),1)
vsp.Update()
if 'z_pos' in vals.tail:
tail_z_pos = vals.tail.z_pos
else:
pass # use above default
if 'Fuel_Tanks' in fuselage:
for tank in fuselage.Fuel_Tanks:
write_fuselage_conformal_fuel_tank(fuse_id, tank, fuel_tank_set_ind)
vsp.SetSetFlag(fuse_id, OML_set_ind, True)
return area_tags
# ----------------------------------------------------------------------------------------------------------------------
# set_section_angles
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def set_section_angles(i,nose_z,tail_z,x_poses,z_poses,heights,widths,length,end_ind,fuse_id):
"""Set fuselage section angles to create a smooth (in the non-technical sense) fuselage shape.
Note that i of 0 corresponds to the first section that is not the end point.
Assumptions:
May fail to give reasonable angles for very irregularly shaped fuselages
Does not work on the nose and tail sections.
Source:
N/A
Inputs:
nose_z [-] # 0.1 is 10% of the fuselage length
widths np.array of [m]
heights np.array of [m]
tail_z [-] # 0.1 is 10% of the fuselage length
Outputs:
Operates on the active OpenVSP model, no direct output
Properties Used:
N/A
"""
divider = 1
if i < 2:
divider = 2
w0 = widths[i]
h0 = heights[i]
w2 = widths[i+2]
h2 = heights[i+2]
x2 = x_poses[i+2]
z2 = z_poses[i+2]
x0 = x_poses[i]*length
x2 = x2*length
z0 = z_poses[i] *length
z2 = z2*length
top_z_diff = (h2/2+z2)-(h0/2+z0)
bot_z_diff = (z2-h2/2)-(z0-h0/2)
y_diff = w2/2-w0/2
x_diff = x2-x0
top_angle = np.tan(top_z_diff/x_diff)/Units.deg / divider
bot_angle = np.tan(-bot_z_diff/x_diff)/Units.deg / divider
side_angle = np.tan(y_diff/x_diff)/Units.deg/ divider
vsp.SetParmVal(fuse_id,"TBSym","XSec_"+str(i+1),0)
vsp.SetParmVal(fuse_id,"TopLAngle","XSec_"+str(i+1),top_angle)
vsp.SetParmVal(fuse_id,"TopLStrength","XSec_"+str(i+1),0.75)
vsp.SetParmVal(fuse_id,"BottomLAngle","XSec_"+str(i+1),bot_angle)
vsp.SetParmVal(fuse_id,"BottomLStrength","XSec_"+str(i+1),0.75)
vsp.SetParmVal(fuse_id,"RightLAngle","XSec_"+str(i+1),side_angle)
vsp.SetParmVal(fuse_id,"RightLStrength","XSec_"+str(i+1),0.75)
return
# ----------------------------------------------------------------------------------------------------------------------
# compute_fuselage_fineness
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def compute_fuselage_fineness(fuselage, x_locs, eff_diams, eff_diam_gradients_fwd):
"""This computes fuselage finenesses for nose and tail.
Assumptions:
Written for OpenVSP 3.16.1
Source:
N/A
Inputs:
0. Pre-loaded VSP vehicle in memory, via import_vsp_vehicle.
1. RCAIDE fuselage [object].
2. Array of x_locations of fuselage segments. (length = L)
3. Array of effective diameters of fuselage segments. (length = L)
4. Array of effective diameter gradients from nose to tail. (length = L-1)
Outputs:
Writes fineness values to RCAIDE fuselage, returns fuselage.
Properties Used:
N/A
"""
segment_list = list(fuselage.segments.keys())
# Compute nose fineness.
x_locs = np.array(x_locs) # Make numpy arrays.
eff_diams = np.array(eff_diams)
min_val = np.min(eff_diam_gradients_fwd[x_locs[:-1]<=0.5]) # Computes smallest eff_diam gradient value in front 50% of fuselage.
x_loc = x_locs[:-1][eff_diam_gradients_fwd==min_val][0] # Determines x-location of the first instance of that value (if gradient=0, gets frontmost x-loc).
fuselage.lengths.nose = (x_loc-fuselage.segments[segment_list[0]].percent_x_location)*fuselage.lengths.total # Subtracts first segment x-loc in case not at global origin.
fuselage.fineness.nose = fuselage.lengths.nose/(eff_diams[x_locs==x_loc][0])
# Compute tail fineness.
x_locs_tail = x_locs>=0.5 # Searches aft 50% of fuselage.
eff_diam_gradients_fwd_tail = eff_diam_gradients_fwd[x_locs_tail[1:]] # Smaller array of tail gradients.
min_val = np.min(-eff_diam_gradients_fwd_tail) # Computes min gradient, where fuselage tapers (minus sign makes positive).
x_loc = x_locs[np.hstack([False,-eff_diam_gradients_fwd==min_val])][-1] # Saves aft-most value (useful for straight fuselage with multiple zero gradients.)
fuselage.lengths.tail = (1.-x_loc)*fuselage.lengths.total
fuselage.fineness.tail = fuselage.lengths.tail/(eff_diams[x_locs==x_loc][0]) # Minus sign converts tail fineness to positive value.
return fuselage
# ----------------------------------------------------------------------------------------------------------------------
# get_fuselage_height
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def get_fuselage_height(fuselage, location):
"""This linearly estimates fuselage height at any percentage point (0,100) along fuselage length.
Assumptions:
Written for OpenVSP 3.16.1
Source:
N/A
Inputs:
0. Pre-loaded VSP vehicle in memory, via import_vsp_vehicle.
1. RCAIDE fuselage [object], containing fuselage.vsp_data.xsec_num in its data structure.
2. Fuselage percentage point [float].
Outputs:
height [m]
Properties Used:
N/A
"""
segment_list = list(fuselage.segments.keys())
for jj in range(1, fuselage.vsp_data.xsec_num): # Begin at second section, working toward tail.
if fuselage.segments[segment_list[jj]].percent_x_location>=location and fuselage.segments[segment_list[jj-1]].percent_x_location<location:
# Find two sections on either side (or including) the desired fuselage length percentage.
a = fuselage.segments[segment_list[jj]].percent_x_location
b = fuselage.segments[segment_list[jj-1]].percent_x_location
a_height = fuselage.segments[segment_list[jj]].height # Linear approximation.
b_height = fuselage.segments[segment_list[jj-1]].height
slope = (a_height - b_height)/(a-b)
height = ((location-b)*(slope)) + (b_height)
break
return height
# ----------------------------------------------------------------------------------------------------------------------
# find_fuse_u_coordinate
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def find_fuse_u_coordinate(x_target,fuse_id,fuel_tank_tag):
"""Determines the u coordinate of an OpenVSP fuselage that matches an x coordinate
Assumptions:
Fuselage is aligned with the x axis
Source:
N/A
Inputs:
x_target [m]
fuse_id <str>
fuel_tank_tag <str>
Outputs:
u_current [-] u coordinate for the requests x position
Properties Used:
N/A
"""
tol = 1e-3
diff = 1000
u_min = 0
u_max = 1
while np.abs(diff) > tol:
u_current = (u_max+u_min)/2
probe_id = vsp.AddProbe(fuse_id,0,u_current,0,fuel_tank_tag+'_probe')
vsp.Update()
x_id = vsp.FindParm(probe_id,'X','Measure')
x_pos = vsp.GetParmVal(x_id)
diff = x_target-x_pos
if diff > 0:
u_min = u_current
else:
u_max = u_current
vsp.DelProbe(probe_id)
return u_current
# ----------------------------------------------------------------------------------------------------------------------
# write_fuselage_conformal_fuel_tank
# ----------------------------------------------------------------------------------------------------------------------
