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import numpy
import time
from string import Template
import matplotlib
matplotlib.use('AGG')
import matplotlib.pyplot as plt
from simulation import Lattice, Geometry
from symbolic.generator import LBM
import symbolic.D2Q9 as D2Q9
lid_speed = 0.1
relaxation_time = 0.52
def MLUPS(cells, steps, time):
return cells * steps / time * 1e-6
def generate_moment_plots(lattice, moments):
for i, m in enumerate(moments):
print("Generating plot %d of %d." % (i+1, len(moments)))
velocity = numpy.ndarray(shape=tuple(reversed(lattice.geometry.inner_size())))
for x, y in lattice.geometry.inner_cells():
velocity[y-1,x-1] = numpy.sqrt(m[1,lattice.memory.gid(x,y)]**2 + m[2,lattice.memory.gid(x,y)]**2)
plt.figure(figsize=(10, 10))
plt.imshow(velocity, origin='lower', cmap=plt.get_cmap('seismic'))
plt.savefig("result/ldc_2d_%02d.png" % i, bbox_inches='tight', pad_inches=0)
def get_cavity_material_map(geometry):
return [
(lambda x, y: x > 0 and x < geometry.size_x-1 and y > 0 and y < geometry.size_y-1, 1), # bulk fluid
(lambda x, y: x == 1 or y == 1 or x == geometry.size_x-2, 2), # left, right, bottom walls
(lambda x, y: y == geometry.size_y-2, 3), # lid
(lambda x, y: x == 0 or x == geometry.size_x-1 or y == 0 or y == geometry.size_y-1, 0) # ghost cells
]
boundary = Template("""
if ( m == 2 ) {
u_0 = 0.0;
u_1 = 0.0;
}
if ( m == 3 ) {
u_0 = $lid_speed;
u_1 = 0.0;
}
""").substitute({
'lid_speed': lid_speed
})
nUpdates = 100000
nStat = 5000
moments = []
print("Initializing simulation...\n")
lbm = LBM(D2Q9)
lattice = Lattice(
descriptor = D2Q9,
geometry = Geometry(600, 600),
layout = (30,1),
padding = (30,1),
align = True,
moments = lbm.moments(optimize = False),
collide = lbm.bgk(f_eq = lbm.equilibrium(), tau = relaxation_time),
boundary_src = boundary)
lattice.apply_material_map(
get_cavity_material_map(lattice.geometry))
lattice.sync_material()
print("Starting simulation using %d cells...\n" % lattice.geometry.volume)
lastStat = time.time()
for i in range(1,nUpdates+1):
lattice.evolve()
if i % nStat == 0:
lattice.sync()
print("i = %4d; %3.0f MLUPS" % (i, MLUPS(lattice.geometry.volume, nStat, time.time() - lastStat)))
moments.append(lattice.get_moments())
lastStat = time.time()
print("\nConcluded simulation.\n")
generate_moment_plots(lattice, moments)
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