def nurbs_example():
r"""Runs an example'''"""
k = dict()
# sample coefficients: Coefficients for generating NACA5410
k['ta_u'] = 0.15
k['ta_l'] = 0.09
k['tb_u'] = 2.9
k['tb_l'] = 2.9
k['alpha_b'] = 6
k['alpha_c'] = -1.
nurbs_foil = NURBS(k)
print(nurbs_foil)
print(nurbs_foil.get_coords_plain())
nurbs_foil.plot_foil(title="NURBS")
def example_nurbs_drag():
r"""Example Nurbs foils drag analysis"""
reynolds = 100000
Cl = 0.2
drags = np.zeros((5, 3))
tb_u = np.linspace(1.8, 2.2, 6)
alpha_b = np.linspace(11.1, 12, 4)
for i in range(1, 6):
for j in range(1, 4):
# make new airfoil
k = dict()
k['ta_u'] = 0.1584
k['ta_l'] = 0.1565
k['tb_u'] = tb_u[i]
k['tb_l'] = 1.8255
k['alpha_b'] = alpha_b[j]
k['alpha_c'] = 3.8270
nurbs_foil = NURBS(k)
# make unique filename
temp_af_filename = "temp_airfoil_{}{}.dat".format(i, j)
# Save coordinates
with open(temp_af_filename, 'w') as nurbs_foil_file:
nurbs_foil_file.write(nurbs_foil.get_coords_plain())
# Let Xfoil do its thing
polar = oper_visc_cl(temp_af_filename, Cl, reynolds, iterlim=1000)
# Save Cd
try:
drags[i - 1][j - 1] = polar[0][0][2]
except IndexError:
raise Warning("Shit! XFOIL didn't converge on NACA{}{}15 at "
"Cl={}.".format(i, j, Cl))
yu, xu, yl, xl, = nurbs_foil.get_coords()
def translated_plt(x, y, *args):
r"""Translated plot
Parameters
----------
x
y
"""
plt.plot(x * 0.8 + (j - .9), y * 0.8 + (i - 0.5), *args)
translated_plt(yl, xl, 'w')
translated_plt(yu, xu, 'w')
os.remove(temp_af_filename)
print(drags)
plt.pcolor(drags, cmap=plt.cm.RdBu)
plt.pcolor(drags, cmap=plt.cm.coolwarm)
cbar = plt.colorbar()
cbar.ax.set_ylabel("Drag coefficient $C_d$")
plt.yticks((.5, 1.5, 2.5, 3.5, 4.5), ("1", "2", "3", "4", "5"))
plt.xticks((.5, 1.5, 2.5), ("1", "2", "3"))
plt.tight_layout()
plt.show()