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()
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 __init__(self,spike,gamma,altitude,n,downstream_factor=1.1,plot_chr=0,clean_mesh=1):
self.spike =copy.copy(spike); self.gamma = gamma; self.altitude =altitude; self.n = n
self.downstream_factor = downstream_factor # percentage down after mesh cross with centre to continue meshing
# constants of iteration
self.plot_chr = plot_chr
self.flip_plug() # flips sign of plug if required
self.slope_init = np.arctan(-(self.spike.lip_x-self.spike.x[0])/(self.spike.lip_y-self.spike.y[0]));
#print(self.slope_init*180/np.pi)
self.tck = interpolate.splrep(self.spike.x,self.spike.y,full_output=0)
(self.p_atm,self.T_atm,self.rho_atm) = gd.standard_atmosphere([altitude])
self.gamma = gamma
self.PR = self.spike.p_c/(self.p_atm)
self.V_l = np.sqrt(2/(self.gamma-1))*self.spike.a_c
# Point storage
self.chr_array = np.array([]) # array for storing points based on ID
# logs characteristics that have not been intercepted
self.ID_left_chr = []
self.ID_right_chr = []
self.ID_jet_boundary = []
self.ID_contour_chr = []
#self.ID_next_chr_jet = []
#self.ID_compression_chr = []
self.ID = 0 # ID of next point, not yet computed
# COMPUTE EXPANSION FAN POINTS (initial data line)
# construction of initial expansion fan
self.compute_initial_expansion_fan()
# TODO: COMPUTE CHAR. NET DOWN TO NOZZLE BASE (when A.x > spike.x[-1], switch centre point jet boundary)
## after computing initial fan, load all point id's into ordered list showing right and left running characteristics that have not been used to compute a downstream point
# TODO: COMPUTE NOZZLE BASE PRESSURE
# while (self.chr_array[self.ID_contour_chr[0]].x <= spike.x.max()):
# pass
# TODO: COMPUTE PLUME DOWNSTREAM OF BASE
# TODO: COMPUTE THRUST PRODUCED
# for point in self.chr_array:
# plt.plot(point.x,point.y,'rX')
# print(self.ID_left_chr)
# print(self.ID_right_chr)
# print(self.ID_jet_boundary)
# print(self.ID_contour_chr)
# base conditions
self.p_b = self.base_pressure()
self.contour_fan = 1
self.new_fan = 1
self.first_base_intercept = 1
self.centre_line_intercept = 0
self.END_SIM = 0
#while (self.chr_array[self.ID_contour_chr[-1]].x <= spike.x.max()):
while self.chr_point_less_zero() and self.contour_converge():
## TODO: COMPUTE EXPANSION FAN UNTIL POINT IS > spike.length in which case, remove from all tracking lists and do not add to chr_array
## CONTOUR FAN
# if (self.contour_fan):
ID_temp = self.ID_right_chr.pop(0)
#print(ID_temp)
if(self.new_fan):
# intersection
self.new_fan = 0
if (self.on_nozzle_contour(self.chr_array[ID_temp])):
new_point = self.contour_point(self.chr_array[ID_temp],plot_chr=self.plot_chr)
self.chr_array = np.append(self.chr_array,new_point)
self.ID += 1
# first point
ID_temp = self.ID_right_chr.pop(0)
new_point = self.general_point(self.chr_array[ID_temp],self.chr_array[self.ID-1],plot_chr=self.plot_chr)
self.chr_array = np.append(self.chr_array,new_point)
self.ID += 1
else:
if (self.first_base_intercept):
self.first_base_intercept = 0
first_base_point = self.chr_array[self.ID_contour_chr[-1]]
#print(self.spike.p_c/self.p_b)
M_b = gd.PR_expansion_mach(self.spike.p_c/self.p_b,self.gamma)
#print(M_b)
theta_b = gd.prandtl_meyer(M_b,self.gamma) - gd.prandtl_meyer(first_base_point.M,self.gamma)
W_b = first_base_point.W
first_base_point = chr_point(self.gamma,self.spike.x[-1],self.spike.y[-1],theta_b,W_b,'contour')
new_point = self.internal_jet_point(first_base_point,self.chr_array[ID_temp],plot_chr=self.plot_chr)
self.chr_array = np.append(self.chr_array,new_point)
self.ID += 1
else:
new_point = self.internal_jet_point(self.chr_array[self.ID_contour_chr[-1]],self.chr_array[ID_temp],plot_chr=self.plot_chr)
self.chr_array = np.append(self.chr_array,new_point)
self.ID += 1
elif(ID_temp==-1):
# self.ID_next_chr_jet.append(self.ID_left_chr.pop(0))
# plt.plot(self.chr_array[self.ID_jet_boundary[-1]].x,self.chr_array[self.ID_jet_boundary[-1]].y,'gx')
new_point = self.general_point(self.chr_array[self.ID_jet_boundary[-1]],self.chr_array[self.ID-1],plot_chr=self.plot_chr)
self.chr_array = np.append(self.chr_array,new_point)
#self.ID_left_chr.append(self.ID)
self.ID += 1
new_point = self.jet_boundary_point(self.chr_array[self.ID_jet_boundary[-1]],self.chr_array[self.ID-1],plot_chr=self.plot_chr)
self.chr_array = np.append(self.chr_array,new_point)
#plt.plot(new_point.x,new_point.y,'gx')
#self.ID_jet_boundary.append(self.ID)
self.ID +=1
self.contour_fan = 0
self.add_break_ID()
self.new_fan = 1
# if (self.centre_line_intercept):
# self.END_SIM = 1
else:
if(self.chr_array[ID_temp].pt_type!="same_fam"):
temp1 = self.same_fam_point(self.chr_array[self.ID_right_chr[0]],self.chr_array[ID_temp])
temp2 = self.general_point(self.chr_array[ID_temp],self.chr_array[self.ID-1])
if (temp1.x < temp2.x) and (temp1.x>self.chr_array[ID_temp].x) :
#self.ID_right_chr.pop(-1); self.ID_left_chr.pop(-1)
#self.compression_offset += 1
#self.plot_chr=1
self.ID_left_chr.pop(-1)
self.ID_right_chr.pop(-1)
#print(temp1.x)
if (self.plot_chr):
plt.plot(self.chr_array[self.ID_right_chr[0]].x,self.chr_array[self.ID_right_chr[0]].y,'bx',self.chr_array[ID_temp].x,self.chr_array[ID_temp].y,'rx')
plt.plot(temp1.x,temp1.y,'go')
#plt.plot([self.chr_array[ID_temp].x, temp1.x],[self.chr_array[ID_temp].y, temp1.y])
self.chr_array = np.append(self.chr_array,temp1)
new_point = self.general_point(self.chr_array[-1],self.chr_array[self.ID-1],plot_chr=self.plot_chr)
#plt.plot(self.chr_array[self.ID-1].x,self.chr_array[self.ID-1].y,'ro')
self.ID += 1
else:
new_point = temp2
if (new_point.x<=self.spike.length):
pass
if (self.plot_chr):
plt.plot([self.chr_array[ID_temp].x, temp2.x],[self.chr_array[ID_temp].y, temp2.y],'k',[self.chr_array[self.ID-1].x, temp2.x],[self.chr_array[self.ID-1].y, temp2.y],'k')
self.ID += 1
self.chr_array = np.append(self.chr_array,new_point)
# ## JET BOUNDARY FAN
# else:
# ID_temp = self.ID_right_chr.pop(0)
# if(self.new_fan):
# new_point = self.general_point(self.chr_array[ID_temp],self.chr_array[self.ID_contour_chr[-1]])
# self.chr_array = np.append(self.chr_array,new_point)
# self.ID += 1
# self.new_fan = 0
# elif (ID_temp == -1):
# new_point=self.jet_boundary_point(self.chr_array[self.ID_next_chr_jet[-1]],self.chr_array[ID_temp -1])
# self.chr_array = np.append(self.chr_array, new_point)
# self.ID += 1
# self.contour_fan = 1
# self.new_fan = 1
# self.add_break_ID()
# else:
# new_point = self.general_point(self.chr_array[ID_temp],self.chr_array[ID_temp-1])
# self.chr_array = np.append(self.chr_array,new_point)
# self.ID += 1
## END OF MOC SECTION #####
# function order is important
if(clean_mesh):
self.clean_data()
self.to_arrays()
self.calc_flow_properties()