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parasite_drag_approx.py
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parasite_drag_approx.py
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from re import T
from networkx.algorithms.clique import find_cliques
from networkx.algorithms.operators.product import _nodes_cross_edges
import openmdao.api as om
import omtools.api as ot
import numpy as np
def lam_func(air_density, air_viscosity, velocity_cruise, x):
cf_lam_comp = 1.328/(air_density*velocity_cruise*x/air_viscosity)**(1/2)
return cf_lam_comp
def turb_func(air_density, air_viscosity, velocity_cruise, x, a):
M = velocity_cruise/a
cf_turb_comp = 0.455/(ot.log10(air_density*velocity_cruise*x/air_viscosity)**2.58 \
*(1 + 0.144*M**2)**0.65)
return cf_turb_comp
def calc_cf(air_density, air_viscosity, length, velocity_cruise, a):
k = 0.7e-5
RE_CRIT_TURB = 38.21*(length/k)**1.053
x_crit_turb = RE_CRIT_TURB*air_viscosity/(velocity_cruise*air_density)
# Can't implement if statements using OM Tools
# if length > x_crit_turb:
# cf_lam_comp = lam_func(air_density, air_viscosity, x_crit_turb, velocity_cruise)
# cf_turb_comp = turb_func(air_density, air_viscosity, velocity_cruise, length, a)
# cf = (cf_lam_comp*x_crit_turb + \
# cf_turb_comp*(length-x_crit_turb)) \
# /length
# else:
# cf = lam_func(air_density, air_viscosity, length, velocity_cruise)
percent_lam = 0.
cf_lam_comp = lam_func(air_density, air_viscosity, length*percent_lam, velocity_cruise)
cf_turb_comp = turb_func(air_density, air_viscosity, velocity_cruise, length, a)
cf = (cf_lam_comp*percent_lam + cf_turb_comp*(length*(1-percent_lam)))/length
# return cf
return cf_turb_comp
def FF_wing(x_over_c, t_over_c, M, sweep_angle):
FF = ((1 + 0.6/x_over_c*t_over_c + 100*t_over_c**4)*(1.34*M**0.18*(ot.cos(sweep_angle))**0.28))
return FF
def FF_fuse(f):
FF = 1 + 60/f**3 + f/400
return FF
def FF_nacelle(f):
FF = 1 + 0.35/f
return FF
def f_coeff(length, max_cross_area):
f = length/(4/np.pi*max_cross_area)**(1/2)
return f
class ParasiteDragApprox(ot.Group):
def initialize(self):
pass
def setup(self):
air_density = self.declare_input('air_density', val=1.225)
air_viscosity = self.declare_input('air_viscosity', val=1.789e-5)
a = self.declare_input('a', val=343)
velocity_cruise = self.declare_input('velocity_cruise', val=50.)
wing_area = self.declare_input('wing_area', val=11.)
wing_mac = self.declare_input('wing_mac', val=1.)
fuse_wetted = self.declare_input('fuse_wetted', val=50.)
fuse_width = self.declare_input('fuse_width', val=2.)
fuse_height = self.declare_input('fuse_height', val=2.)
fuse_length = self.declare_input('fuse_length', val=5.)
nose_wetted = self.declare_input('nose_wetted', val=1e-5)
nose_length = self.declare_input('nose_length', val=1.)
htail_wetted = self.declare_input('htail_wetted', val=2.)
htail_mac = self.declare_input('htail_mac', val=0.5)
vtail_wetted = self.declare_input('vtail_wetted', val=2.)
vtail_mac = self.declare_input('vtail_mac', val=0.5)
tail_boom_area = self.declare_input('tail_boom_area', val=5)
tail_boom_radius = self.declare_input('tail_boom_radius', val=0.5)
tail_boom_length = self.declare_input('tail_boom_length', val=2.)
sweep_angle = self.declare_input('sweep_angle', val=0.)
M = velocity_cruise/a
cf_wing = calc_cf(air_density, air_viscosity, wing_mac, velocity_cruise, a)
cf_fuse = calc_cf(air_density, air_viscosity, fuse_length, velocity_cruise, a)
cf_nose = calc_cf(air_density, air_viscosity, nose_length, velocity_cruise, a)
cf_htail = calc_cf(air_density, air_viscosity, htail_mac, velocity_cruise, a)
cf_vtail = calc_cf(air_density, air_viscosity, vtail_mac, velocity_cruise, a)
cf_tail_boom = calc_cf(air_density, air_viscosity, tail_boom_length, velocity_cruise, a)
M = velocity_cruise/a
t_over_c = 0.12
x_over_c = 0.4
FFWing = FF_wing(x_over_c, t_over_c, M, sweep_angle)
t_over_c = 0.15
x_over_c = 0.4
FFHTail = FF_wing(x_over_c, t_over_c, M, sweep_angle)
FFVTail = FF_wing(x_over_c, t_over_c, M, sweep_angle)
fuse_cross_section_area = fuse_width*fuse_height
fFuse = f_coeff(fuse_length, fuse_cross_section_area)
FFFuse = FF_fuse(fFuse)
nose_cross_section_area = fuse_cross_section_area
fNose = f_coeff(nose_length, nose_cross_section_area)
FFNose = FF_fuse(fNose)
tail_boom_cross_section_area = tail_boom_radius
fTailBoom = f_coeff(tail_boom_length, tail_boom_cross_section_area)
FFTailBoom = FF_fuse(fTailBoom)
# Q = 1.0 # interference factor
Q = 1.1 # interference factor
areaRatioWing = 2*wing_area/wing_area
areaRatioFuse = fuse_wetted/wing_area
areaRatioNose = nose_wetted/wing_area
areaRatioHTail = htail_wetted/wing_area
areaRatioVTail = vtail_wetted/wing_area
areaRatioTailBoom = tail_boom_area/wing_area
cD0 = Q*(cf_wing*FFWing*areaRatioWing + cf_fuse*FFFuse*areaRatioFuse + \
cf_nose*FFNose*areaRatioNose + cf_htail*FFHTail*areaRatioHTail + \
cf_vtail*FFVTail*areaRatioVTail + cf_tail_boom*FFTailBoom*areaRatioTailBoom)
wing_term = cf_wing*FFWing*areaRatioWing
htail_term = cf_htail*FFHTail*areaRatioHTail
vtail_term = cf_vtail*FFVTail*areaRatioVTail
fuse_term = cf_fuse*FFFuse*areaRatioFuse
nose_term = cf_nose*FFNose*areaRatioNose
tail_boom_term = 2*cf_tail_boom*FFTailBoom*areaRatioTailBoom
self.register_output('cD0', cD0)
# self.register_output('FFWing', FFWing)
self.register_output('cf_wing', cf_wing)
self.register_output('FFFuse', FFFuse)
self.register_output('wing_term', wing_term)
self.register_output('htail_term', htail_term)
self.register_output('vtail_term', vtail_term)
self.register_output('fuse_term', fuse_term)
self.register_output('nose_term', nose_term)
self.register_output('tail_boom_term', tail_boom_term)