This commit is contained in:
Georg ´Brantegger
2022-06-23 09:20:37 +02:00
13 changed files with 661 additions and 10 deletions

6
.gitignore vendored
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2bignored.txt
functions/__pycache__/
*__pycache__/
.vscode/settings.json
__pycache__/Ausgleichsbecken_class_file.cpython-38.pyc
__pycache__/Ausgleichsbecken.cpython-38.pyc
__pycache__/functions.cpython-38.pyc
*.pyc

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from Ausgleichsbecken import FODE_function, get_h_halfstep, get_p_halfstep
from pressure_conversion import pressure_conversion
class Ausgleichsbecken_class:
# units
area_unit = r'$\mathrm{m}^2$'
area_outflux_unit = r'$\mathrm{m}^2$'
level_unit = 'm'
volume_unit = r'$\mathrm{m}^3$'
flux_unit = r'$\mathrm{m}^3/\mathrm{s}$'
time_unit = 's'
pressure_unit = 'Pa'
# init
def __init__(self,area,outflux_area,level_min,level_max,timestep = 1):
self.area = area # base area of the rectangular structure
self.area_outflux = outflux_area # area of the outlet towards the pipeline
self.level_min = level_min # lowest allowed water level
self.level_max = level_max # highest allowed water level
self.timestep = timestep # timestep of the simulation
# setter
def set_volume(self):
self.volume = self.level*self.area
def set_initial_level(self,initial_level):
self.level = initial_level
self.set_volume()
def set_influx(self,influx):
self.influx = influx
def set_outflux(self,outflux):
self.outflux = outflux
# getter
def get_area(self):
print('The base area of the cuboid reservoir is', self.area, self.area_unit)
def get_outflux_area(self):
print('The outflux area from the cuboid reservoir to the pipeline is', \
self.area_outflux, self.area_outflux_unit)
def get_level(self):
print('The current level in the reservoir is', self.level , self.level_unit)
def get_crit_levels(self):
print('The critical water levels in the reservoir are: \n',\
' Minimum:', self.level_min , self.level_unit , '\n',\
' Maximum:', self.level_max , self.level_unit )
def get_volume(self):
print('The current water volume in the reservoir is', self.volume, self.volume_unit)
def get_timestep(self):
print('The timestep for the simulation is' , self.timestep, self.time_unit)
def get_influx(self):
print('The current influx is', self.influx, self.flux_unit)
def get_outflux(self):
print('The current outflux is', self.outflux, self.flux_unit)
# methods
def update_level(self,timestep):
net_flux = self.influx-self.outflux
delta_V = net_flux*timestep
new_level = (self.volume+delta_V)/self.area
return new_level
def e_RK_4(self):
# Update to deal with non constant pipeline pressure!
yn = self.outflux/self.area_outflux
h = self.level
dt = self.timestep
p,_ = pressure_conversion(self.pressure,self.pressure_unit,'Pa')
p_hs,_ = pressure_conversion(self.pressure,self.pressure_unit,'Pa')
alpha = (self.area_outflux/self.area-1)
h_hs = self.update_level(dt/2)
Y1 = yn
Y2 = yn + dt/2*FODE_function(Y1, h, alpha, self.pressure)
Y3 = yn + dt/2*FODE_function(Y2, h_hs, alpha, p_hs)
Y4 = yn + dt*FODE_function(Y3, h_hs, alpha, p_hs)
ynp1 = yn + dt/6*(FODE_function(Y1, h, alpha, p)+2*FODE_function(Y2, h_hs, alpha, p_hs)+ \
2*FODE_function(Y3, h_hs, alpha, p_hs)+ FODE_function(Y4, h, alpha, p))
self.outflux = ynp1*self.area_outflux

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# convert to Pa
def bar_to_pa(p):
return p*1e5
def mWS_to_pa(p):
return p*9.80665*1e3
def torr_to_pa(p):
return p*133.322
def atm_to_pa(p):
return p*101.325*1e3
def psi_to_pa(p):
return p*6894.8
# convert from Pa
def pa_to_bar(p):
return p*1e-5
def pa_to_mWS(p):
return p*1/(9.80665*1e3)
def pa_to_torr(p):
return p/133.322
def pa_to_atm(p):
return p*1/(101.325*1e3)
# converstion function
def pa_to_psi(p):
return p/6894.8
def pressure_conversion(pressure, input_unit = 'bar', target_unit = 'Pa'):
p = pressure
if input_unit.lower() == 'bar':
p_pa = bar_to_pa(p)
elif input_unit.lower() == 'mws':
p_pa = mWS_to_pa(p)
elif input_unit.lower() == 'torr':
p_pa = torr_to_pa(p)
elif input_unit.lower() == 'atm':
p_pa = atm_to_pa(p)
elif input_unit.lower() == 'psi':
p_pa = psi_to_pa(p)
elif input_unit.lower() == 'pa':
p_pa = p
else:
raise Exception('Given input unit not recognised. \n Known units are: Pa, bar, mWs, Torr, atm, psi')
if target_unit.lower() == 'bar':
return pa_to_bar(p_pa), target_unit
elif target_unit.lower() == 'mws':
return pa_to_mWS(p_pa), target_unit
elif target_unit.lower() == 'torr':
return pa_to_torr(p_pa), target_unit
elif target_unit.lower() == 'atm':
return pa_to_atm(p_pa), target_unit
elif target_unit.lower() =='psi':
return pa_to_psi(p_pa), target_unit
elif target_unit.lower() == 'pa':
return p_pa, target_unit
else:
raise Exception('Given target unit not recognised. \n Known units are: Pa, bar, mWs, Torr, atm, psi')
# testing_pressure_conversion
if __name__ == '__main__':
p = 1
unit_dict = ['Pa','Bar','Torr','Atm','MWS','psi']
for input_unit in unit_dict:
for target_unit in unit_dict:
converted_p = pressure_conversion(p,input_unit,target_unit)
print(input_unit,target_unit)
print(converted_p)

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import numpy as np
def Volume_trend(influx, outflux, timestep=1, V_0=0):
'''
Returns the trend and the volume and the final volume, defined
by influx and outflux patterns. The optional parameter timestep
defines the time increment over which the fluxes are changing.
'''
net_flux = influx-outflux
delta_V = net_flux*timestep
V_trend = V_0+np.cumsum(delta_V)
V_end = V_trend[-1]
return V_end, V_trend
def Height_trend(V_trend, area=1, h_crit_low=-np.inf, h_crit_high=np.inf):
'''
Returns the trend and the height and the final height, defined
by influx and outflux patterns as well as the crosssection area.
The optional parameters h_crit_low/high indicate limits that the height
should never exceed. If this occures, TRUE is returned in the corresponding
h_crit_flag.
'''
h_trend = V_trend/area
h_crit_flag_low = np.any(h_trend <= h_crit_low)
h_crit_flag_high = np.any(h_trend >= h_crit_high)
h_end = h_trend[-1]
return h_trend, h_end, h_crit_flag_low, h_crit_flag_high
def get_h_halfstep(initial_height, influx, outflux, timestep, area):
h0 = initial_height
Q_in = influx
Q_out = outflux
dt = timestep
A = area
h_halfstep = h0+1/A*(Q_in-Q_out)*dt/2
def get_p_halfstep(p0, p1):
p_halfstep = (p0+p1)/2
def FODE_function(x, h, alpha, p, rho=1000., g=9.81):
f = x*abs(x)/h*alpha+g-p/(rho*h)
return f
def e_RK_4(yn, h, dt, Q0, Q1, A0, A1, p0, p1):
alpha = (A1/A0-1)
h_hs = get_h_halfstep(h, Q0, Q1, dt, A0)
p_hs = get_p_halfstep(p0, p1)
Y1 = yn
Y2 = yn + dt/2*FODE_function(Y1, h, alpha, p0)
Y3 = yn + dt/2*FODE_function(Y2, h_hs, alpha, p_hs)
Y4 = yn + dt*FODE_function(Y3, h_hs, alpha, p_hs)
ynp1 = yn + dt/6*(FODE_function(Y1, h, alpha, p)+2*FODE_function(Y2, h_hs, alpha, p_hs)+ \
2*FODE_function(Y3, h_hs, alpha, p_hs)+ FODE_function(Y4, h, alpha, p))
## testing
# if __name__ == "__main__":
# influx = np.full([1, 100], 6)
# outflux = np.full_like(influx, 4)
# V_end, V_trend = Volume_trend(influx, outflux, timestep=0.5, V_0 = 100)
# print(V_end)
# print(V_trend)

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@@ -1,5 +1,5 @@
from Ausgleichsbecken import FODE_function, get_h_halfstep, get_p_halfstep
from functions.pressure_conversion import pressure_conversion
from pressure_conversion import pressure_conversion
class Ausgleichsbecken_class:
# units
area_unit = r'$\mathrm{m}^2$'

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@@ -2,19 +2,19 @@
"cells": [
{
"cell_type": "code",
"execution_count": 10,
"execution_count": 2,
"metadata": {},
"outputs": [],
"source": [
"import numpy as np\n",
"from Ausgleichsbecken_class_file import Ausgleichsbecken_class\n",
"import matplotlib.pyplot as plt\n",
"from functions.pressure_conversion import pressure_conversion"
"from pressure_conversion import pressure_conversion"
]
},
{
"cell_type": "code",
"execution_count": 11,
"execution_count": 3,
"metadata": {},
"outputs": [],
"source": [
@@ -39,13 +39,13 @@
},
{
"cell_type": "code",
"execution_count": 12,
"execution_count": 4,
"metadata": {},
"outputs": [
{
"data": {
"application/vnd.jupyter.widget-view+json": {
"model_id": "c7ff9cd7c3ae4d21a32d833650fa73a3",
"model_id": "6a4020b97d834285b3b362c8b1f27e47",
"version_major": 2,
"version_minor": 0
},

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# convert to Pa
def bar_to_pa(p):
return p*1e5
def mWS_to_pa(p):
return p*9.80665*1e3
def torr_to_pa(p):
return p*133.322
def atm_to_pa(p):
return p*101.325*1e3
def psi_to_pa(p):
return p*6894.8
# convert from Pa
def pa_to_bar(p):
return p*1e-5
def pa_to_mWS(p):
return p*1/(9.80665*1e3)
def pa_to_torr(p):
return p/133.322
def pa_to_atm(p):
return p*1/(101.325*1e3)
# converstion function
def pa_to_psi(p):
return p/6894.8
def pressure_conversion(pressure, input_unit = 'bar', target_unit = 'Pa'):
p = pressure
if input_unit.lower() == 'bar':
p_pa = bar_to_pa(p)
elif input_unit.lower() == 'mws':
p_pa = mWS_to_pa(p)
elif input_unit.lower() == 'torr':
p_pa = torr_to_pa(p)
elif input_unit.lower() == 'atm':
p_pa = atm_to_pa(p)
elif input_unit.lower() == 'psi':
p_pa = psi_to_pa(p)
elif input_unit.lower() == 'pa':
p_pa = p
else:
raise Exception('Given input unit not recognised. \n Known units are: Pa, bar, mWs, Torr, atm, psi')
if target_unit.lower() == 'bar':
return pa_to_bar(p_pa), target_unit
elif target_unit.lower() == 'mws':
return pa_to_mWS(p_pa), target_unit
elif target_unit.lower() == 'torr':
return pa_to_torr(p_pa), target_unit
elif target_unit.lower() == 'atm':
return pa_to_atm(p_pa), target_unit
elif target_unit.lower() =='psi':
return pa_to_psi(p_pa), target_unit
elif target_unit.lower() == 'pa':
return p_pa, target_unit
else:
raise Exception('Given target unit not recognised. \n Known units are: Pa, bar, mWs, Torr, atm, psi')
# testing_pressure_conversion
if __name__ == '__main__':
p = 1
unit_dict = ['Pa','Bar','Torr','Atm','MWS','psi']
for input_unit in unit_dict:
for target_unit in unit_dict:
converted_p = pressure_conversion(p,input_unit,target_unit)
print(input_unit,target_unit)
print(converted_p)

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{
"cells": [
{
"cell_type": "code",
"execution_count": 37,
"metadata": {},
"outputs": [],
"source": [
"#imports\n",
"import numpy as np\n",
"import matplotlib.pyplot as plt"
]
},
{
"cell_type": "code",
"execution_count": 38,
"metadata": {},
"outputs": [],
"source": [
"#define constants\n",
"\n",
"g = 9.81 # gravitational acceleration [m/s²]\n",
"\n",
"L = 100 # length of pipeline [m]\n",
"rho = 1000 # density of water [kg/m³]\n",
"D = 1 # pipe diameter \n",
"Q0 = 2 # initial flow in whole pipe [m³/s]\n",
"h = 20 # water level in upstream reservoir [m]\n",
"n = 10 # number of pipe segments in discretization\n",
"nt = 150 # number of time steps\n",
"f_coeff = 0.1 # lambda = 0.01 Friction loss coefficient [m]\n",
"c = 400 # propagation velocity of the pressure wave\n",
"\n"
]
},
{
"cell_type": "code",
"execution_count": 39,
"metadata": {},
"outputs": [],
"source": [
"# preparing the discretization and initial conditions\n",
"\n",
"dx = L/n # length of each pipe segment\n",
"dt = dx/c # timestep according to method of characterisitics\n",
"nn = n+1 # number of nodes\n",
"pl_vec = np.arange(0,nn*dx,dx) # pl = pipe-length. position of the nodes on the pipeline\n",
"t_vec = np.arange(0,(nt)*dt,dt) # time vector\n",
"\n",
"v0 = Q0/(D**2/4*np.pi)\n",
"p0 = (rho*g*h-v0**2*rho/2)\n",
"\n",
"# storage vectors for old parameters\n",
"v_old = np.full(nn,v0)\n",
"p_old = p0-(f_coeff*pl_vec/D*rho/2*v0**2) # ref Wikipedia: Rohrreibungszahls\n",
"\n",
"# storage vectors for new parameters\n",
"v_new = np.zeros_like(v_old)\n",
"p_new = np.zeros_like(p_old)\n",
"\n",
"# storage vector for time evolution of parameters at node nn (at reservoir)\n",
"p_nn = np.zeros_like(t_vec)\n",
"v_nn = np.zeros_like(t_vec)\n",
"\n"
]
},
{
"cell_type": "code",
"execution_count": 40,
"metadata": {},
"outputs": [],
"source": [
"%matplotlib qt\n",
"# time loop\n",
"\n",
"fig = plt.figure()\n",
"ax1 = fig.add_subplot(111)\n",
"lo1, = ax1.plot(pl_vec,np.full_like(pl_vec,p0),marker='.')\n",
"ax1.set_ylim([-20*p0,20*p0])\n",
"\n",
"for it in range(nt):\n",
" # set boundary conditions\n",
" v_new[-1] = 0 # in front of the instantaneously closing valve, the velocity is 0\n",
" p_new[0] = p0 # hydrostatic pressure from the reservoir\n",
"\n",
" # calculate the new parameters at first and last node\n",
" v_new[0] = v_old[1]+1/(rho*c)*(p0-p_old[1])-f_coeff*dt/(2*D)*abs(v_old[1])*v_old[1]\n",
" p_new[-1] = p_old[-2]+rho*c*v_old[-2]-rho*c*f_coeff*dt/(2*D) *abs(v_old[-2])*v_old[-2]\n",
"\n",
" # calculate parameters at second to second-to-last nodes \n",
" #equation 2-30 plus 2-31 (and refactor for v_i^j+1) in block 2\n",
"\n",
" for i in range(1,nn-1):\n",
" v_new[i] = 0.5*(v_old[i-1]+v_old[i+1])+0.5/(rho*c)*(p_old[i-1]-p_old[i+1]) \\\n",
" -f_coeff*dt/(4*D)*(abs(v_old[i-1])*v_old[i-1]+abs(v_old[i+1])*v_old[i+1])\n",
"\n",
" p_new[i] = 0.5*rho*c*(v_old[i-1]-v_old[i+1])+0.5*(p_old[i-1]+p_old[i+1]) \\\n",
" -rho*c*f_coeff*dt/(4*D)*(abs(v_old[i-1])*v_old[i-1]-abs(v_old[i+1])*v_old[i+1])\n",
" \n",
" lo1.set_xdata(pl_vec)\n",
" lo1.set_ydata(p_new)\n",
" ax1.set_title(str(t_vec[it]))\n",
" fig.canvas.draw()\n",
" plt.pause(0.05)\n",
"\n",
" # store parameters of node 0 (at reservoir)\n",
" p_nn[it] = p_old[-1]\n",
" v_nn[it] = v_old[-1]\n",
"\n",
" # prepare for next loop\n",
" p_old = p_new\n",
" v_old = v_new\n",
"\n",
"\n",
"\n"
]
},
{
"cell_type": "code",
"execution_count": 42,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"[<matplotlib.lines.Line2D at 0x14c45f0bfd0>]"
]
},
"execution_count": 42,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"plt.plot(v_nn)"
]
}
],
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