def get_max_cl(Re, r):
"""
Analyze airfoil at a fixed Re,
changing aoa from 10 to 15 by 0.1
and returns cl, cd, aoa that makes maximum cl
"""
xf = XFoil()
if r <= 0.175:
xf.airfoil = naca6409
else:
xf.airfoil = naca2412
xf.Re = Re
xf.Re = Re
xf.max_iter = 200
xf.n_crit = 9.00
xf.xtr = [1.00, 1.00]
xf.M = 0
a_seq, cl_seq, cd_seq, cm_seq, cp_seq = xf.aseq(10, 15, 0.1)
# ignore nan by making it 0
cl_seq = np.nan_to_num(cl_seq)
# find the maximum cl
cl_maxi = np.max(cl_seq)
# index of the maximum cl
idx = np.argmax(cl_seq)
return round(cl_maxi, 2), round(a_seq[idx], 2), round(cd_seq[idx], 2)
def get_torque(angular_velocity):
torque_sum_small = 0
torque_sum_large = 0
w = angular_velocity
for key, value in dfdict.items():
value["blade_velocity"] = value['r_position'] * w
value["relative_velocity"] = round(
math.sqrt(value["blade_velocity"]**2 + value["wind_velocity"]**2),
2)
value["arctan"] = math.degrees(
math.atan2(value["wind_velocity"], value["blade_velocity"]))
aoa = round(value["arctan"] - value["pitch_angle"], 2)
value["angle_of_attack"] = aoa
re_n = round(
value["relative_velocity"] * value["chord_length"] / 0.00001511, 3)
value["Reynolds_number"] = re_n
xf = XFoil()
if key < 13:
xf.airfoil = naca6409
else:
xf.airfoil = naca2412
xf.Re = re_n
xf.max_iter = 100
xf.n_crit = 9.00
xf.xtr = [1.00, 1.00]
xf.M = 0
value["Cl"], value["Cd"], value["Cm"], value["Cp"] = xf.a(aoa)
force_reference = 0.5 * density * value["relative_velocity"]**2
if math.isnan(value["Cl"]):
value["torque"] = 0
else:
lift = value["Cl"] * force_reference * 0.0125 * value[
'chord_length']
drag = value["Cd"] * force_reference * 0.0125 * value[
'chord_length']
value["torque"] = value["r_position"] * (
lift * math.sin(math.radians(value["pitch_angle"])) -
drag * math.cos(math.radians(value["pitch_angle"])))
if key < 13:
torque_sum_small += value["torque"]
else:
pass
if key > 0:
torque_sum_large += value["torque"]
else:
pass
df2 = pd.DataFrame.from_dict(dfdict, orient="index")
df_collection.append(df2)
torque_sum_avg = 0.5 * (torque_sum_small + torque_sum_large)
return torque_sum_avg
def total_dict(angular_velocity):
torque_sum = 0
w = angular_velocity
for key, value in dfdict.items():
value["blade_velocity"] = value['r_position'] * w
value["relative_velocity"] = round(
math.sqrt(value["blade_velocity"]**2 + value["wind_velocity"]**2),
2)
value["arctan"] = math.degrees(
math.atan2(value["wind_velocity"], value["blade_velocity"]))
aoa = round(value["arctan"] - value["pitch_angle"], 1)
value["angle_of_attack"] = aoa
re_n = round(value["relative_velocity"] * value["chord_length"] /
0.00001511)
value["Reynolds_number"] = re_n
xf = XFoil()
if key < 13:
xf.airfoil = naca6409
else:
xf.airfoil = naca2412
xf.Re = round(re_n / 100) * 100
xf.max_iter = 200
xf.n_crit = 9.00
xf.xtr = [1.00, 1.00]
xf.M = 0
c_l, c_d, c_m, c_p = xf.a(aoa)
force_reference = 0.5 * density * value["relative_velocity"]**2
if math.isnan(c_l):
pass
else:
value["Cl"] = c_l
value["Cd"] = c_d
value["Cm"] = c_m
value["Cp"] = c_p
lift = c_l * force_reference * 0.0125 * value['chord_length']
drag = c_d * force_reference * 0.0125 * value['chord_length']
value["lift"] = lift
value["drag"] = drag
# value["torque"] = value["r_position"] * lift * math.sin(math.radians(value["pitch_angle"]))
torque = value["r_position"] * (
lift * math.sin(math.radians(value["pitch_angle"])) -
drag * math.cos(math.radians(value["pitch_angle"])))
value["torque"] = torque
torque_sum += torque
xf.reset_bls()
# detailed_df = pd.DataFrame.from_dict(dfdict, orient="index")
# print(detailed_df)
print(torque_sum, angular_velocity)
return dfdict, torque_sum
#TODO: CST airfoil for Xfoil
cst_u = [ 0.135283, 0.088574, 0.177210, 0.080000, 0.231590, 0.189572, 0.192000]
cst_l = [-0.101390, -0.007993, -0.240000, -0.129790, -0.147840, -0.000050, 0.221251]
xx, yu, yl, t0, R0 = cst_foil(101, np.array(cst_u), np.array(cst_l), x=None, t=0.0954, tail=0.002)
x = np.concatenate((np.flip(xx[1:]), xx[1:]), axis=0)
y = np.concatenate((np.flip(yu[1:]), yl[1:]), axis=0)
foil = Airfoil(x, y)
#TODO: Xfoil
xf = XFoil()
xf.print = False
xf.max_iter = 40
xf.airfoil = foil
xf.xtr = [0.0, 0.0]
Minf = 0.2
AoA = 8.0
Re = 1e7
fname = 'feature-xfoil.txt'
xf.M = Minf
xf.Re = Re
cl, cd, cm, cp = xf.a(AoA)
x, cp = xf.get_cp_distribution()
with open(fname, 'w') as f:
f.write('%10s %15.6f \n'%('Minf', Minf))
f.write('%10s %15.6f \n'%('AoA', AoA))