Source code for svcco.sv_interface.ROM.models

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"""
Contains all ROM building blocks (currently onky 1D)
"""
import numpy as np
from collections import defaultdict
from scipy.signal import argrelextrema


# todo: move modeling stuff from Mesh class and io_1d in ROM base class. ZeroD, OneD inherit from base class


[docs]class ZeroD(object): """ Contains all 0D building blocks """ def __init__(self, mesh, params): self.mesh = mesh self.params = params self.model = {}
[docs] def generate(self): """ bla """ for k in ['branches', 'junctions']: self.model[k] = {'R_poiseuille': defaultdict(list), 'L': defaultdict(list), 'C': defaultdict(list)} if k == 'branches': self.model[k]['stenosis_coefficient'] = defaultdict(list) # loop branches for (br, ids) in self.mesh.cell_data['id'].items(): # loop segments for seg, _ in enumerate(ids): self.model['branches']['stenosis_coefficient'][br] += [self.get_factor_stenosis(br, seg)] # segment length length = self.mesh.cell_data['length'][br][seg] # segment average radius radius = self.get_segment_avg_radius(br, seg) # calculate 0D elements self.model['branches']['R_poiseuille'][br] += [self.get_resistance_viscous(length, radius)] self.model['branches']['L'][br] += [self.get_inductance(length, radius)] self.model['branches']['C'][br] += [self.get_capacitance(length, radius)] return self.model
[docs] def get_factor_stenosis(self, br, seg): """ See (7) in Mirramezani and Shadden, 2020 """ return 1.52 * self.params.density / 2 * self.mesh.cell_data['stenosis'][br][seg]
[docs] def get_resistance_viscous(self, length, avg_radius): """ Calculate viscous resistance using Poiseuille flow """ return 8.0 * self.params.viscosity * length / (np.pi * (avg_radius ** 4))
[docs] def get_capacitance(self, length, avg_radius): """ Compute capacitance using Poiseuille flow """ return 3.0 * length * np.pi * (avg_radius ** 2) / (2 * self.get_vessel_stiffness(avg_radius))
[docs] def get_inductance(self, length, avg_radius): """ Compute inductance using Poiseuille flow """ return length * self.params.density / (np.pi * (avg_radius ** 2))
[docs] def get_segment_avg_radius(self, br, seg): """ Compute average segment radius from inlet and outlet area """ a0, a1 = self.mesh.cell_data['area'][br][seg] return (np.sqrt(a0 / np.pi) + np.sqrt(a1 / np.pi)) / 2.0
[docs] def get_vessel_stiffness(self, r): """ Get vessel stiffness depending on constitutive law """ if self.params.material_model == "OLUFSEN": k1 = self.params.olufsen_material_k1 k2 = self.params.olufsen_material_k2 k3 = self.params.olufsen_material_k3 return k1 * np.exp(k2 * r) + k3 elif self.params.material_model == "LINEAR": return self.params.linear_material_ehr else: raise ValueError("Material type " + self.params.material_type + " unknown (choose OLUFSEN or LINEAR).")