Georg_Brantegger/Python-DT_Slot_3
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added "vectorized" version of method of characteristics

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Brantegger Georg
2022-08-09 13:51:57 +02:00
parent 38c809ef49
commit 7394d6c964
2 changed files with 43 additions and 89 deletions
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32
Druckrohrleitung/Druckrohrleitung_class_file.py
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@@ -254,3 +254,35 @@ class Druckrohrleitung_class:
# else one can overwrite data by accidient and change two variables at once without noticing # else one can overwrite data by accidient and change two variables at once without noticing
self.p_old = self.p.copy() self.p_old = self.p.copy()
self.v_old = self.v.copy() self.v_old = self.v.copy()
def timestep_characteristic_method_vectorized(self):
# use the method of characteristics to calculate the pressure and velocities at all nodes except the boundary ones
# they are set with the .set_boundary_conditions_next_timestep() method beforehand
# constants for cleaner formula
rho = self.density # density of liquid
c = self.c # pressure propagation velocity
f_D = self.f_D # Darcy friction coefficient
dt = self.dt # timestep
D = self.dia # pipeline diameter
g = self.g # graviational acceleration
alpha = self.angle # pipeline angle
# Vectorized loop
self.v[1:-1] = 0.5*(self.v_old[2:]+self.v_old[:-2])-0.5/(rho*c)*(self.p_old[2:]-self.p_old[:-2]) \
+dt*g*np.sin(alpha)-f_D*dt/(4*D)*(np.abs(self.v_old[2:])*self.v_old[2:]+np.abs(self.v_old[:-2])*self.v_old[:-2])
self.p[1:-1] = 0.5*(self.p_old[2:]+self.p_old[:-2])-0.5*rho*c*(self.v_old[2:]-self.v_old[:-2]) \
+f_D*rho*c*dt/(4*D)*(np.abs(self.v_old[2:])*self.v_old[2:]-np.abs(self.v_old[:-2])*self.v_old[:-2])
# update overall min and max values for pressure and velocity per node
self.p_min = np.minimum(self.p_min,self.p)
self.p_max = np.maximum(self.p_max,self.p)
self.v_min = np.minimum(self.v_min,self.v)
self.v_max = np.maximum(self.v_max,self.v)
# prepare for next call
# use .copy() to write data to another memory location and avoid the usual python reference pointer
# else one can overwrite data by accidient and change two variables at once without noticing
self.p_old = self.p.copy()
self.v_old = self.v.copy()

98
Druckrohrleitung/Druckrohrleitung_test_steady_state.ipynb
View File

@@ -2,7 +2,7 @@
"cells": [ "cells": [
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 1, "execution_count": null,
"metadata": {}, "metadata": {},
"outputs": [], "outputs": [],
"source": [ "source": [
@@ -22,7 +22,7 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 2, "execution_count": null,
"metadata": {}, "metadata": {},
"outputs": [], "outputs": [],
"source": [ "source": [
@@ -80,48 +80,9 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 3, "execution_count": null,
"metadata": {}, "metadata": {},
"outputs": [ "outputs": [],
{
"name": "stdout",
"output_type": "stream",
"text": [
"The pipeline has the following attributes: \n",
"----------------------------- \n",
"Length = 1013.0 m \n",
"Diameter = 0.9 m \n",
"Hydraulic head = 105.0 m \n",
"Number of segments = 50 \n",
"Number of nodes = 51 \n",
"Length per segments = 20.26 m \n",
"Pipeline angle = 0.104 rad \n",
"Pipeline angle = 5.95° \n",
"Darcy friction factor = 0.014 \n",
"Density of liquid = 1000.0 kg/m³ \n",
"Pressure wave vel. = 500.0 m/s \n",
"Simulation timestep = 0.04052 s \n",
"----------------------------- \n",
"Velocity and pressure distribution are vectors and are accessible by the .v and .p attribute of the pipeline object\n",
"The pipeline has the following attributes: \n",
"----------------------------- \n",
"Length = 1013.0 m \n",
"Diameter = 0.9 m \n",
"Hydraulic head = 105.0 m \n",
"Number of segments = 50 \n",
"Number of nodes = 51 \n",
"Length per segments = 20.26 m \n",
"Pipeline angle = 0.104 rad \n",
"Pipeline angle = 5.95° \n",
"Darcy friction factor = 0.014 \n",
"Density of liquid = 1000.0 kg/m³ \n",
"Pressure wave vel. = 500.0 m/s \n",
"Simulation timestep = 0.04052 s \n",
"----------------------------- \n",
"Velocity and pressure distribution are vectors and are accessible by the .v and .p attribute of the pipeline object\n"
]
}
],
"source": [ "source": [
"# create objects\n", "# create objects\n",
"\n", "\n",
@@ -137,7 +98,7 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 4, "execution_count": null,
"metadata": {}, "metadata": {},
"outputs": [], "outputs": [],
"source": [ "source": [
@@ -168,7 +129,7 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 5, "execution_count": null,
"metadata": {}, "metadata": {},
"outputs": [], "outputs": [],
"source": [ "source": [
@@ -193,48 +154,9 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 6, "execution_count": null,
"metadata": {}, "metadata": {},
"outputs": [ "outputs": [],
{
"name": "stdout",
"output_type": "stream",
"text": [
"The cuboid reservoir has the following attributes: \n",
"----------------------------- \n",
"Base area = 74.0 m² \n",
"Outflux area = 0.636 m² \n",
"Current level = 8.0 m\n",
"Critical level low = 0.0 m \n",
"Critical level high = inf m \n",
"Volume in reservoir = 592.0 m³ \n",
"Current influx = 0.773 m³/s \n",
"Current outflux = 0.773 m³/s \n",
"Current outflux vel = 1.215 m/s \n",
"Current pipe pressure = 7.854 mWS \n",
"Simulation timestep = 0.001013 s \n",
"Density of liquid = 1000.0 kg/m³ \n",
"----------------------------- \n",
"\n",
"The pipeline has the following attributes: \n",
"----------------------------- \n",
"Length = 1013.0 m \n",
"Diameter = 0.9 m \n",
"Hydraulic head = 105.0 m \n",
"Number of segments = 50 \n",
"Number of nodes = 51 \n",
"Length per segments = 20.26 m \n",
"Pipeline angle = 0.104 rad \n",
"Pipeline angle = 5.95° \n",
"Darcy friction factor = 0.014 \n",
"Density of liquid = 1000.0 kg/m³ \n",
"Pressure wave vel. = 500.0 m/s \n",
"Simulation timestep = 0.04052 s \n",
"----------------------------- \n",
"Velocity and pressure distribution are vectors and are accessible by the .v and .p attribute of the pipeline object\n"
]
}
],
"source": [ "source": [
"for it_pipe in range(1,nt+1):\n", "for it_pipe in range(1,nt+1):\n",
"# for each pipeline timestep, execute nt_eRK4 timesteps of the reservoir code\n", "# for each pipeline timestep, execute nt_eRK4 timesteps of the reservoir code\n",
@@ -257,7 +179,7 @@
" v_boundary_res[it_pipe] = pipe.get_current_velocity_distribution()[0]\n", " v_boundary_res[it_pipe] = pipe.get_current_velocity_distribution()[0]\n",
"\n", "\n",
" # perform the next timestep via the characteristic method\n", " # perform the next timestep via the characteristic method\n",
" pipe.timestep_characteristic_method()\n", " pipe.timestep_characteristic_method_vectorized()\n",
"\n", "\n",
" # prepare for next loop\n", " # prepare for next loop\n",
" p_old = pipe.get_current_pressure_distribution()\n", " p_old = pipe.get_current_pressure_distribution()\n",
@@ -283,7 +205,7 @@
}, },
{ {
"cell_type": "code", "cell_type": "code",
"execution_count": 7, "execution_count": null,
"metadata": {}, "metadata": {},
"outputs": [], "outputs": [],
"source": [ "source": [