Georg_Brantegger/Python-DT_Slot_3
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important numerical stability improvement of the convergence method

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Brantegger Georg
2022-09-13 14:54:03 +02:00
parent b9634e378b
commit b5e60dd083
2 changed files with 16 additions and 5 deletions
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10
Kraftwerk/Kraftwerk_class_file.py
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@@ -31,7 +31,7 @@ class Kraftwerk_class:
# getter # getter
def get_current_Q(self): def get_current_Q(self):
Q = 0 Q = 0.
for i in range(self.n_turbines): for i in range(self.n_turbines):
Q += self.turbines[i].get_current_Q() Q += self.turbines[i].get_current_Q()
return Q return Q
@@ -88,20 +88,26 @@ class Kraftwerk_class:
c = convergence_parameters[6] # pressure wave propagtation velocity c = convergence_parameters[6] # pressure wave propagtation velocity
rho = convergence_parameters[7] # density of the liquid rho = convergence_parameters[7] # density of the liquid
dt = convergence_parameters[8] # timestep of the characteristic method dt = convergence_parameters[8] # timestep of the characteristic method
p_old = convergence_parameters[9] # pressure of previous timestep
Q_old = self.get_current_Q() Q_old = self.get_current_Q()
v_old = Q_old/area_pipe v_old = Q_old/area_pipe
while iteration_change > eps: while iteration_change > eps:
p_new = p-rho*c*(v_old-v)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v)*v p_new = p-rho*c*(v_old-v)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v)*v
# print(p_new)
p_new = p_old+(p_new-p_old)/3
# print(p_new)
self.set_pressure(p_new) self.set_pressure(p_new)
Q_new = self.get_current_Q() Q_new = self.get_current_Q()
v_new = Q_new/area_pipe v_new = Q_new/area_pipe
# print(Q_old,Q_new)
iteration_change = abs(Q_old-Q_new) iteration_change = abs(Q_old-Q_new)
Q_old = Q_new.copy() Q_old = Q_new.copy()
v_old = v_new.copy() v_old = v_new.copy()
p_old = p_new.copy()
i = i+1 i = i+1
if i == 1e6: if i == 1e6:
print('did not converge') print('did not converge')

9
Turbinen/Turbinen_class_file.py
View File

@@ -169,23 +169,28 @@ class Francis_Turbine:
c = convergence_parameters[6] # pressure wave propagtation velocity c = convergence_parameters[6] # pressure wave propagtation velocity
rho = convergence_parameters[7] # density of the liquid rho = convergence_parameters[7] # density of the liquid
dt = convergence_parameters[8] # timestep of the characteristic method dt = convergence_parameters[8] # timestep of the characteristic method
p_old = convergence_parameters[9] # pressure of previous timestep
Q_old = self.get_current_Q() Q_old = self.get_current_Q()
v_old = Q_old/area_pipe v_old = Q_old/area_pipe
while iteration_change > eps: while iteration_change > eps:
p_new = p-rho*c*(v_old-v)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v)*v p_new = p-rho*c*(v_old-v)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v)*v
# print(p_new)
p_new = p_old+(p_new-p_old)/3
# print(p_new)
self.set_pressure(p_new) self.set_pressure(p_new)
Q_new = self.get_current_Q() Q_new = self.get_current_Q()
v_new = Q_new/area_pipe v_new = Q_new/area_pipe
# print(Q_old,Q_new)
iteration_change = abs(Q_old-Q_new) iteration_change = abs(Q_old-Q_new)
Q_old = Q_new.copy() Q_old = Q_new.copy()
v_old = v_new.copy() v_old = v_new.copy()
p_old = p_new.copy()
i = i+1 i = i+1
if i == 1e6: if i == 1e6:
print('did not converge') print('did not converge')
break break
# print(i) # print(i)
# self.get_current_Q()