Newer
Older
def test_calc_dimensionless_gridspacing():
"""
this method tests the nondimensional gridspacing postprocessing function calc_dimensionless_gridspacing
a volume mesh will be created. boundary meshes will be extracted of the volume mesh.
then a simple couette-velocity-field is defined
calc_dimensionless_gridspacing needs to compute accurately the Delta+-Values
"""
from ntrfc.meshquality.nondimensionals import calc_dimensionless_gridspacing
import pyvista as pv
import numpy as np
def runtest(height, length, width):
# 11**3 nodes are enough
nodes = 11
# needs to be something simple
mu_0 = 1 # dynamic viscosity
rho = 1
velocity = 2
gradient = velocity / height
# analytical solution
span_x = width / (nodes - 1)
span_y = height / (nodes - 1)
span_z = length / (nodes - 1)
wallshearstress = mu_0 * gradient
wallshearvelocity = np.sqrt(wallshearstress / rho)
deltaxplus = wallshearvelocity * span_x / mu_0
deltayplus = wallshearvelocity * span_y / mu_0
deltazplus = wallshearvelocity * span_z / mu_0
# define the mesh
xrng = np.arange(0, nodes, 1, dtype=np.float32)
yrng = np.arange(0, nodes, 1, dtype=np.float32)
zrng = np.arange(0, nodes, 1, dtype=np.float32)
x, y, z = np.meshgrid(xrng, yrng, zrng)
grid = pv.StructuredGrid(x, y, z)
# scale the mesh
grid.points /= nodes - 1
grid.points *= np.array([width, height, length])
# define velocityfield
bounds = grid.bounds
min_z = bounds[4]
grid["U"] = [gradient * (grid.cell_centers().points[::,1][i]-min_z) * np.array([0,0,1]) for i in range(grid.number_of_cells)]
grid["rho"] = np.ones(grid.number_of_cells)
# extract surface
surface = grid.extract_surface()
facecellids = surface.surface_indices()
upperwallids = []
lowerwallids = []
for faceid in facecellids:
cell = surface.extract_cells(faceid)
if all(cell.points[::, 1] == 0):
lowerwallids.append(faceid)
elif all(cell.points[::, 1] == height):
upperwallids.append(faceid)
lowerwall = surface.extract_cells(lowerwallids)
upperwall = surface.extract_cells(upperwallids)
lowerwall["U"] = [gradient * (lowerwall.cell_centers().points[::,1][i]-min_z) * np.array([0,0,1]) for i in range(lowerwall.number_of_cells)]
upperwall["U"] = [gradient * (upperwall.cell_centers().points[::,1][i]-min_z) * np.array([0,0,1]) for i in range(upperwall.number_of_cells)]
lowerwall["rho"] = np.ones(lowerwall.number_of_cells) * rho
upperwall["rho"] = np.ones(upperwall.number_of_cells) * rho
dimless_gridspacings = calc_dimensionless_gridspacing(grid, [lowerwall, upperwall], "U", "rho", mu_0)
assert all(np.isclose(deltazplus, dimless_gridspacings[
"DeltaXPlus"], rtol=0.05)), "calc_dimensionelss_gridspcing in x direction not accurate"
assert all(np.isclose(deltayplus, dimless_gridspacings[
"DeltaYPlus"], rtol=0.05)), "calc_dimensionelss_gridspcing in y direction not accurate"
assert all(np.isclose(deltaxplus, dimless_gridspacings[
"DeltaZPlus"], rtol=0.05)), "calc_dimensionelss_gridspcing in z direction not accurate"
runtest(height=1, length=1, width=1)
runtest(height=2, length=1, width=1)
runtest(height=1, length=2, width=1)
runtest(height=1, length=1, width=2)
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
def test_calc_dimensionless_gridspacing():
"""
this method tests the nondimensional gridspacing postprocessing function calc_dimensionless_gridspacing
a volume mesh will be created. boundary meshes will be extracted of the volume mesh.
then a simple couette-velocity-field is defined
calc_dimensionless_gridspacing needs to compute accurately the Delta+-Values
"""
from ntrfc.meshquality.nondimensionals import calc_dimensionless_yplus
import pyvista as pv
import numpy as np
def runtest(height, length, width):
# 11**3 nodes are enough
nodes = 11
# needs to be something simple
mu_0 = 1 # dynamic viscosity
rho = 1
velocity = 2
gradient = velocity / height
# analytical solution
span_x = width / (nodes - 1)
span_y = height / (nodes - 1)
span_z = length / (nodes - 1)
wallshearstress = mu_0 * gradient
wallshearvelocity = np.sqrt(wallshearstress / rho)
deltayplus = wallshearvelocity * span_y/2 / mu_0
# define the mesh
xrng = np.arange(0, nodes, 1, dtype=np.float32)
yrng = np.arange(0, nodes, 1, dtype=np.float32)
zrng = np.arange(0, nodes, 1, dtype=np.float32)
x, y, z = np.meshgrid(xrng, yrng, zrng)
grid = pv.StructuredGrid(x, y, z)
# scale the mesh
grid.points /= nodes - 1
grid.points *= np.array([width, height, length])
# define velocityfield
bounds = grid.bounds
min_z = bounds[4]
grid["U"] = [gradient * (grid.cell_centers().points[::,1][i]-min_z) * np.array([0,0,1]) for i in range(grid.number_of_cells)]
grid["rho"] = np.ones(grid.number_of_cells)
# extract surface
surface = grid.extract_surface()
facecellids = surface.surface_indices()
upperwallids = []
lowerwallids = []
for faceid in facecellids:
cell = surface.extract_cells(faceid)
if all(cell.points[::, 1] == 0):
lowerwallids.append(faceid)
elif all(cell.points[::, 1] == height):
upperwallids.append(faceid)
lowerwall = surface.extract_cells(lowerwallids)
upperwall = surface.extract_cells(upperwallids)
lowerwall["U"] = [gradient * (lowerwall.cell_centers().points[::,1][i]-min_z) * np.array([0,0,1]) for i in range(lowerwall.number_of_cells)]
upperwall["U"] = [gradient * (upperwall.cell_centers().points[::,1][i]-min_z) * np.array([0,0,1]) for i in range(upperwall.number_of_cells)]
lowerwall["rho"] = np.ones(lowerwall.number_of_cells) * rho
upperwall["rho"] = np.ones(upperwall.number_of_cells) * rho
dimless_gridspacings = calc_dimensionless_yplus(grid, [lowerwall, upperwall], "U", "rho", mu_0)
assert all(np.isclose(deltayplus, dimless_gridspacings[
"yPlus"], rtol=0.05)), "calc_dimensionelss_gridspcing in x direction not accurate"
runtest(height=1, length=1, width=1)
runtest(height=2, length=1, width=1)
runtest(height=1, length=2, width=1)
runtest(height=1, length=1, width=2)