def flight_simulation( ):
#While loop runs until rocket velocity is less than 10 feet/s
while (True):
#Calculates atmospheric density at altitude x and passes density to RK4 fxn.
rho = compDensity(x)
#Calculates mDot and thrust as tank pressure drops (if applicable) and altitude changes
n_thrust, n_mdot = compThrust2(thrust, m_dot, (initial_mass * pr_ratio) , propellant_mass)
#Calculates Cd as a fx of mach number
K = compTemp(x)
mach = compMach(v,K)
n_cd = waveDrag(Cd,mach)
#RK4 function to solve rocket differential equation. Returns v(t) approximated using Runge-Kutta 4th order method
v = RK4(t,v, mass, final_mass, n_cd, n_thrust, n_mdot, gravity, area, step_size, rho)
#Computes current displacement using reimen sum
x = x + ((current_velocity + v)/2 * step_size)
if (v > 10) or (t < 10):
if (n_thrust > 0):
mass = mass - n_mdot * step_size
propellant_mass = propellant_mass - n_mdot * step_size
bo_time = t
bo_velocity = v
bo_thrust = n_thrust
bo_mdot = n_mdot
bo_alt = x
if(max_dynamic_pressure < (.5 * rho * v**2)):
max_dynamic_pressure = (.5 * rho * v**2)
#Thrust is off, but propellant is still being drained by the tank pressue fluid (if applicable, such as blowdown system)
elif (n_thrust == 0 and n_mdot != 0):
mass = mass - n_mdot * step_size
propellant_mass = propellant_mass - n_mdot * step_size
else:
#Leave this for clarity, though redundant
mass = mass
x_graph = np.append(x_graph, x)
v_graph = np.append(v_graph, v)
current_velocity = v
#steps the while loop forward in time
t = t + step_size
t_graph = np.append(t_graph,t)
else:
break
def flight_simulation(self):
gravity = 32.174 # ft / s^2
step_size = .01
#initialize rocket data from __init__
thrust = self.thrust
m_dot = self.m_dot
area = self.area
cd = self.cd
pr_ratio = self.pr_ratio
initial_mass = self.initial_mass
propellant_mass = self.propellant_mass
final_mass = self.final_mass
mass = initial_mass
#Initializes a bunch of stuff locally
x_graph = np.array([0])
v_graph = np.array([0])
t_graph = np.array([0])
#Generally, do not change these. Describes initial conditions and
#initializes the variables
t=0
v=0
x = 0
rho=0
bo_time = 0
bo_velocity = 0
current_velocity = 0
max_q = 0
max_q_velocity = 0
max_q_altitude = 0
max_q_acceleration = 0
#While loop runs until rocket velocity is less than 10 feet/s
while (x >= 0):
#Calculates atmospheric density at altitude x and passes density to RK4 fxn.
rho = compDensity(x)
#Calculates mDot and thrust as tank pressure drops (if applicable) and altitude changes
n_thrust, n_mdot = compThrust2(thrust, m_dot, (initial_mass * pr_ratio), propellant_mass)
#Calculates Cd as a fx of mach number
K = compTemp(x)
mach = compMach(v,K)
n_cd = waveDrag(cd,mach)
#RK4 function to solve rocket differential equation. Returns v(t) approximated using Runge-Kutta 4th order method
v = RK4(t,v, mass, final_mass, n_cd, n_thrust, n_mdot, gravity, area, step_size, rho)
#Computes current displacement using reimen sum
x = x + ((current_velocity + v)/2 * step_size)
if (n_thrust > 0):
mass = mass - n_mdot * step_size
propellant_mass = propellant_mass - n_mdot * step_size
#Get burnout
bo_time = t
bo_velocity = v
bo_thrust = n_thrust
bo_mdot = n_mdot
bo_alt = x
bo_mass = mass
bo_accel = (thrust/mass)/32.2 - ((area * n_cd * .5 * rho * v**2)/mass)/32.2 - 1
bo_mdot = n_mdot
temp_max_q = n_cd * rho * 1/2 * v**2
if (max_q < temp_max_q):
max_q = temp_max_q
max_q_velocity = v
max_q_altitude = x
max_q_time = t
#using the time and step size to find slope of velocity graph
if(np.size(v_graph) > 3 ):
max_q_acceleration = (v_graph[int(np.floor(t/step_size))] - v_graph[int(np.floor(t/step_size)-1)])/step_size
#Thrust is off, but propellant is still being drained by the tank pressue fluid (if applicable, such as blowdown system)
elif (n_thrust == 0 and n_mdot != 0):
mass = mass - n_mdot * step_size
propellant_mass = propellant_mass - n_mdot * step_size
else:
#Leave this for clarity, though redundant
mass = mass
x_graph = np.append(x_graph, x)
v_graph = np.append(v_graph, v)
current_velocity = v
#steps the while loop forward in time
t = t + step_size
t_graph = np.append(t_graph,t)
#returns a tuple containing vectors containing displacement, velocity and time, maximum velocity, burnouttime, and max altitude
return x_graph, v_graph, t_graph, bo_velocity, bo_time, np.max(x_graph), bo_alt, bo_mass, t_graph[np.argmax(x_graph)], bo_accel, bo_mdot, max_q, max_q_velocity, max_q_altitude, max_q_acceleration, max_q_time
print('\nTHRUST TESTED: ' +str(thrust))
#Establishes mDot from thrust, gravity and isp
mDot = thrust/(gravity * isp)
print(thrust)
print('Starting mDot: ' + str(mDot))
while (True):
#Calculates atmospheric density at altitude x and passes density to RK4 fxn.
rho = compDensity(x)
#Calculates mDot and thrust as tank pressure drops
nThrust, nMdot = compThrust2(thrust, mDot, (initialMass * prRatio) , propellantMass)
#Calculates Cd as a fx of mach number
K = compTemp(x)
mach = compMach(v,K)
nCd = waveDrag(Cd,mach)
#RK4 fxn
v = RK4(t,v, mass, finalMass, nCd, nThrust, nMdot, gravity, Area, stepSize, rho)
# Greater than 30 so that program will terminate when velocity is trivial
# or t<10 to make sure loop does not break when object is first accelerating
if (v > 30) or (t < 10):
if (nThrust > 0 and (mass > finalMass)):
mass = mass - nMdot * stepSize
propellantMass = propellantMass - nMdot * stepSize
burnOutTime = t
burnOutVelocity = v
thrustAtBO = nThrust
nMdotAtBO = nMdot