def compute_initial_expansion_fan(self):
M_max = gd.PR_expansion_mach(self.PR, self.gamma)
# print('M_max: ' + str(M_max))
mach_fan = np.linspace(1.1, M_max, self.n)
(T_ratio, p_ratio, rho_ratio,
a_ratio) = gd.isentropic_ratios(0, mach_fan, self.gamma)
V_fan = a_ratio * self.spike.a_c * mach_fan
W_fan = V_fan / self.V_l
theta_fan = -gd.prandtl_meyer(mach_fan, self.gamma) + self.slope_init
angle_fan = gd.mach_angle(mach_fan)
# print(180/np.pi*np.arcsin(np.sqrt((gamma-1)/2*(1/W_fan**2-1))))
# print(W_fan)
# print(angle_fan*180/np.pi)
x_fan = np.ones(angle_fan.shape) * self.spike.lip_x
y_fan = np.ones(angle_fan.shape) * self.spike.lip_y
#print(theta_fan*180/np.pi)
# print(gd.mach_angle_velocity_ratio(gd.prandtl_meyer(2.3,gamma),0.3,gamma))
initial_point = self.contour_point(chr_point(self.gamma, x_fan[0],
y_fan[0], theta_fan[0],
W_fan[0], 'N/A'),
plot_chr=self.plot_chr)
self.ID += 1
self.ID_contour_chr.pop(0)
self.chr_array = np.append(self.chr_array, initial_point)
for point in x_fan[1:-1]:
temp_point = chr_point(self.gamma, x_fan[self.ID], y_fan[self.ID],
theta_fan[self.ID], W_fan[self.ID], 'N/A')
new_point = self.general_point(temp_point,
self.chr_array[self.ID - 1],
plot_chr=self.plot_chr)
# adding to arrays
self.chr_array = np.append(self.chr_array, new_point)
self.ID += 1
first_jet = chr_point(self.gamma, x_fan[-1], y_fan[-1], theta_fan[-1],
W_fan[-1], 'N/A')
second_jet = self.jet_boundary_point(first_jet,
self.chr_array[self.ID - 1],
plot_chr=self.plot_chr)
self.chr_array = np.append(self.chr_array, second_jet)
#self.ID_jet_boundary.append(self.ID)
self.ID += 1
self.add_break_ID()
def design_nozzle(self):
# discrete contour design variables
self.M = np.linspace(1, self.M_e, self.n)
self.A = self.A_t * gd.expansion_ratio(1, self.M, self.gamma)
self.alpha = gd.prandtl_meyer(self.M_e, self.gamma) - gd.prandtl_meyer(
self.M, self.gamma) + gd.mach_angle(self.M)
self.l = (self.r_e - np.sqrt(
np.abs(self.r_e**2 -
(self.A * self.M * np.sin(self.alpha) / np.pi)))) / np.sin(
self.alpha)
self.x = self.l * np.cos(self.alpha)
self.y = self.l * np.sin(self.alpha)
self.centre_spike()
self.length = self.x.max()