def c_f_m_flap(wing, control, mach, cg):
"""return flap force and moment coefficient derivatives, empirical method."""
y_scalar = control['b_2'] / abs(control['b_2'])
s = wing['planform']
b = span(wing['aspect_ratio'], s)
taper = wing['taper']
c_r = root_chord(wing['aspect_ratio'], s, taper)
if y_scalar > 0:
y_w = b * control['b_2'] / 2
x_w = abs(y_w) * tan(deg2rad(wing['sweep_LE']))
c_r_f = y_chord(abs(control['b_1']) * b / 2, c_r, b, taper)
c_t_f = y_chord(abs(control['b_2']) * b / 2, c_r, b, taper)
else:
y_w = b * control['b_1'] / 2
x_w = abs(y_w) * tan(deg2rad(wing['sweep_LE']))
c_r_f = y_chord(abs(control['b_2']) * b / 2, c_r, b, taper)
c_t_f = y_chord(abs(control['b_1']) * b / 2, c_r, b, taper)
s_f = flap_area(wing, control)
b_f = flap_span(wing, control)
ar_f = (b_f**2) / s_f
taper_f = c_t_f / c_r_f
y_f = y_mac(ar_f, s_f, taper_f)
cbar_f = mac(ar_f, s_f, taper_f)
ac_f = array(
[y_f * tan(deg2rad(wing['sweep_LE'])) + cbar_f / 4, y_f * y_scalar, 0])
ac = (ac_f + array([x_w, y_w, 0]) +
array([wing['station'], wing['buttline'], wing['waterline']]))
r = (ac - cg) * array([-1, 1, -1])
f = c_f_delta_flap(wing, control, mach)
m = cross(r, f)
c = concatenate((f, m))
return c
def avl_section(y, cs, wing, mirror, cs_name, duplicate_sign=1):
"""create avl wing section."""
b = span(wing['aspect_ratio'], wing['planform'], mirror=mirror)
c_r = root_chord(wing['aspect_ratio'],
wing['planform'],
wing['taper'],
mirror=mirror)
wing_root_le_pnt = avl.Point(wing['station'], wing['buttline'],
wing['waterline'])
if mirror:
le_point = avl.Point(
x=wing_root_le_pnt.x + y * tan(deg2rad(wing['sweep_LE'])),
y=y,
z=wing_root_le_pnt.z + y * tan(deg2rad(wing['dihedral'])))
chord = y_chord(y, c_r, b, wing['taper'])
else:
le_point = avl.Point(x=wing_root_le_pnt.x +
y * tan(deg2rad(wing['sweep_LE'])),
y=wing_root_le_pnt.y,
z=wing_root_le_pnt.z + y)
chord = y_chord(y, c_r, b * 2, wing['taper'])
if cs == 0:
section = avl.Section(leading_edge_point=le_point,
chord=chord,
airfoil=avl.NacaAirfoil(wing['airfoil']))
else:
control = avl.Control(name=cs_name,
gain=1,
x_hinge=1 - cs['cf_c'],
duplicate_sign=duplicate_sign)
section = avl.Section(leading_edge_point=le_point,
chord=chord,
airfoil=avl.NacaAirfoil(wing['airfoil']),
controls=[control])
return section
def flap_area(wing, control):
"""return flapped area."""
s = wing['planform']
b = span(wing['aspect_ratio'], s)
taper = wing['taper']
c_r = root_chord(wing['aspect_ratio'], s, taper)
s_a = ((control['b_2'] - control['b_1']) * b / 4 *
(y_chord(abs(control['b_2']) * b / 2, c_r, b, taper) +
y_chord(abs(control['b_1']) * b / 2, c_r, b, taper)))
return s_a
def print_vt(wing):
b = span(wing['aspect_ratio'], wing['planform'], mirror=0)
c_r = root_chord(wing['aspect_ratio'], wing['planform'], wing['taper'])
c_t = c_r * wing['taper']
x = wing['station'] + array([
0, b / 2 * tan(deg2rad(wing['sweep_LE'])),
b / 2 * tan(deg2rad(wing['sweep_LE'])) + c_t, c_r, 0
])
z = array([0, b, b, 0, 0]) + wing['waterline']
y = array([0, 0, 0, 0, 0])
return x, y, z
def d_epsilon_d_alpha(self, ht, mach):
"""return downwash gradient wrt angle of attack, empirical method."""
ar = self.wing['aspect_ratio'] # []
taper = self.wing['taper'] # []
root_chord_wing = root_chord(ar, self.wing['planform'], taper) # [ft]
root_chord_ht = root_chord(ht['aspect_ratio'], ht['planform'],
ht['taper']) # [ft]
x_wh = (ht['station'] + root_chord_ht / 4) - (
self.wing['station'] + root_chord_wing / 4) # [ft]
z_wh = ht['waterline'] - self.wing['waterline'] # [ft]
b = span(ar, self.wing['planform']) # [ft]
r = 2 * x_wh / b # []
m = 2 * z_wh / b # []
k_ar = (1 / ar) - 1 / (1 + ar**1.7) # []
k_taper = (10 - 3 * taper) / 7 # []
k_mr = (1 - (m / 2)) / (r**0.333) # []
sweep_25 = sweep_x(ar, taper, self.wing['sweep_LE'], 0.25) # [deg]
beta = sqrt(1 - mach**2) # []
de_da = 4.44 * beta * (k_ar * k_taper * k_mr *
sqrt(cos(deg2rad(sweep_25))))**1.19 # []
return de_da
def print_wing(wing):
b = span(wing['aspect_ratio'], wing['planform'])
c_r = root_chord(wing['aspect_ratio'], wing['planform'], wing['taper'])
c_t = c_r * wing['taper']
x = wing['station'] + array([
0, b / 2 * tan(deg2rad(wing['sweep_LE'])),
b / 2 * tan(deg2rad(wing['sweep_LE'])) + c_t, c_r,
b / 2 * tan(deg2rad(wing['sweep_LE'])) + c_t,
b / 2 * tan(deg2rad(wing['sweep_LE'])), 0
])
y = array([0, b / 2, b / 2, 0, -b / 2, -b / 2, 0])
z = wing['waterline'] + array([
0, b / 2 * tan(deg2rad(wing['dihedral'])),
b / 2 * tan(deg2rad(wing['dihedral'])), 0,
b / 2 * tan(deg2rad(wing['dihedral'])),
b / 2 * tan(deg2rad(wing['dihedral'])), 0
])
return x, y, z
from src.modeling.trapezoidal_wing import mac, root_chord, span, sweep_x, x_mac, y_chord, y_mac
from test.test_library import is_close
ar = 5
s = 10
sweep_le = 30
taper = 0.5
c_bar = mac(ar, s, taper)
cr = root_chord(ar, s, taper)
b = span(ar, s)
sweep = sweep_x(ar, taper, sweep_le, 0.5)
y = y_mac(ar, s, taper)
x = x_mac(3, sweep_le)
c = y_chord(0.25, cr, b, taper)
out = list()
out.append((is_close(c_bar, 1.46659)))
out.append(is_close(b, 7.071067))
out.append(is_close(cr, 1.8856))
out.append(is_close(c, 1.81895))
out.append(is_close(x, 1.73205))
out.append(is_close(y, 1.5713))
out.append(is_close(sweep, 23.942))
if any(out):
print("trapezoidal wing test passed!")
else:
print("trapezoidal wing test failed")