pylbm.stencil.Velocity

class pylbm.stencil.Velocity(dim=None, num=None, vx=None, vy=None, vz=None)

Create a velocity.

Parameters
  • dim (int, optional) – The dimension of the velocity.

  • num (int, optional) – The number of the velocity in the numbering convention of Lattice-Boltzmann scheme.

  • vx (int, optional) – The x component of the velocity vector.

  • vy (int, optional) – The y component of the velocity vector.

  • vz (int, optional) – The z component of the velocity vector.

dim

The dimension of the velocity.

Type

int

num

The number of the velocity in the numbering convention of Lattice-Boltzmann scheme.

vx

The x component of the velocity vector.

Type

int

vy

The y component of the velocity vector.

Type

int

vz

The z component of the velocity vector.

Type

int

v
Type

list

Examples

Create a velocity with the dimension and the number

>>> v = Velocity(dim = 1, num = 2)
>>> v
velocity 2
 vx: -1

Create a velocity with a direction

>>> v = Velocity(vx=1, vy=1)
>>> v
velocity 5
 vx: 1
 vy: 1

Notes

from __future__ import print_function, division
from six.moves import range
import matplotlib
import matplotlib.pyplot as plt
import matplotlib.colors as colors
import matplotlib.cm as cm
from matplotlib.patches import FancyArrowPatch
from mpl_toolkits.mplot3d import Axes3D, proj3d

import pylbm
import numpy as np

class Arrow3D(FancyArrowPatch):
    def __init__(self, xs, ys, zs, *args, **kwargs):
        FancyArrowPatch.__init__(self, (0,0), (0,0), *args, **kwargs)
        self._verts3d = xs, ys, zs

    def draw(self, renderer):
        xs3d, ys3d, zs3d = self._verts3d
        xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, renderer.M)
        self.set_positions((xs[0],ys[0]),(xs[1],ys[1]))
        FancyArrowPatch.draw(self, renderer)

def Velocities_1D(n):
    dim = 1
    fig = plt.figure(dim, figsize=(8, 4), facecolor='white')
    fig.clf()
    xmin, xmax, ymin, ymax = 1000, -1000, -1, 1
    e = 0.2
    for k in range((2*n+1)**dim):
        v = pylbm.stencil.Velocity(dim = dim, num = k)
        x = v.vx
        xmin = min(xmin, x)
        xmax = max(xmax, x)
        couleur_texte = 0.
        couleur_trait = 0.5
        plt.text(x, 0., str(v.num), color=[couleur_texte]*3,
                 horizontalalignment='center',verticalalignment='center',
                 fontsize=15)

    plt.plot([xmin, xmax], [0, 0], ':', color=[couleur_trait]*3)
    plt.text(0., ymax+2*e, "Velocities numbering {0:1d}D".format(dim),fontsize=20,
        verticalalignment='center', horizontalalignment='center', color='b')
    plt.arrow(xmin-e, ymin-e, 1, 0, head_width=0.05*dim, head_length=0.1, fc='b', ec='b')
    plt.text(xmin-e+.5, ymin-1.5*e, 'x', color='b',
        verticalalignment='center', horizontalalignment='center')
    plt.axis('off')
    plt.xlim(xmin-2*e, xmax+2*e)
    plt.ylim(ymin-2*e, ymax+2*e)
    plt.draw()

def Velocities_2D(n):
    dim = 2
    fig = plt.figure(dim, figsize=(8, 8), facecolor='white')
    fig.clf()
    xmin, xmax, ymin, ymax = 1000, -1000, 1000, -1000
    e = .5
    for k in range((2*n+1)**dim):
        v = pylbm.stencil.Velocity(dim = dim, num = k)
        x = v.vx
        y = v.vy
        xmin = min(xmin, x)
        xmax = max(xmax, x)
        ymin = min(ymin, y)
        ymax = max(ymax, y)
        couleur_texte = 0.
        couleur_trait = 0.5
        plt.text(x, y, str(v.num), color=[couleur_texte]*3,
                 horizontalalignment='center',verticalalignment='center',
                 fontsize=15)
    for x in range(xmin, xmax+1):
        plt.plot([x, x], [ymin, ymax], ':', color=[couleur_trait]*3)
    for y in range(ymin, ymax+1):
        plt.plot([xmin, xmax], [y, y], ':', color=[couleur_trait]*3)
    plt.text(0., ymax+2*e, "Velocities numbering {0:1d}D".format(dim),fontsize=20,
        verticalalignment='center', horizontalalignment='center', color='b')
    plt.arrow(xmin-e, ymin-e, 1, 0, head_width=0.05*dim, head_length=0.1, fc='b', ec='b')
    plt.arrow(xmin-e, ymin-e, 0, 1, head_width=0.05*dim, head_length=0.1, fc='b', ec='b')
    plt.text(xmin-e+.5, ymin-1.5*e, 'x', color='b',
        verticalalignment='center', horizontalalignment='center')
    plt.text(xmin-1.5*e, ymin-e+.5, 'y', color='b',
        verticalalignment='center', horizontalalignment='center')
    plt.axis('off')
    plt.xlim(xmin-2*e, xmax+2*e)
    plt.ylim(ymin-2*e, ymax+2*e)
    plt.draw()

def Velocities_3D(n):
    dim = 3
    couleur_tour = "k"
    fig = plt.figure(dim, figsize=(8, 8), facecolor='white')
    fig.clf()
    ax = fig.add_subplot(111, projection='3d')
    xmin, xmax, ymin, ymax, zmin, zmax = 1000, -1000, 1000, -1000, 1000, -1000
    e = .5
    for k in range((2*n+1)**dim):
        v = pylbm.stencil.Velocity(dim = dim, num = k)
        x = v.vx
        y = v.vy
        z = v.vz
        xmin = min(xmin, x)
        xmax = max(xmax, x)
        ymin = min(ymin, y)
        ymax = max(ymax, y)
        zmin = min(zmin, z)
        zmax = max(zmax, z)
        couleur_texte = [.5+.5*x, 0., .5-.5*x]
        couleur_trait = 0.5
        ax.text(x, y, z, str(v.num), color=couleur_texte,
                 horizontalalignment='center',verticalalignment='center',
                 fontsize=15)
    for x in range(xmin, xmax+1):
        for y in range(ymin, ymax+1):
            ax.plot([x, x], [y, y], [zmin, zmax], ':', color=[couleur_trait]*3)
    for x in range(xmin, xmax+1):
        for z in range(zmin, zmax+1):
            ax.plot([x, x], [ymin, ymax], [z, z], ':', color=[couleur_trait]*3)
    for z in range(zmin, zmax+1):
        for y in range(ymin, ymax+1):
            ax.plot([xmin, xmax], [y, y], [z, z], ':', color=[couleur_trait]*3)

    XS, YS = np.meshgrid([-1,1],[-1,1])
    ZS = np.zeros(XS.shape)
    couleur_plan = .8
    for x in [-1,0,1]:
        ax.plot_surface(ZS+x, XS, YS,
            rstride=1, cstride=1, color=[.5+.5*x, 0., .5-.5*x],
            shade=False, alpha=0.2,
            antialiased=False, linewidth=0)
    ax.text(0., 0., zmax+2*e, "Velocities numbering {0:1d}D".format(dim), fontsize=20,
        verticalalignment='center', horizontalalignment='center', color=couleur_tour)
    vx = Arrow3D([xmax+e,xmax+e+1],[ymin-e,ymin-e],[zmin-e,zmin-e],
        mutation_scale=20, lw=1, arrowstyle="-|>", color=couleur_tour)
    ax.add_artist(vx)
    vy = Arrow3D([xmax+e,xmax+e],[ymin-e,ymin-e+1],[zmin-e,zmin-e],
        mutation_scale=20, lw=1, arrowstyle="-|>", color=couleur_tour)
    ax.add_artist(vy)
    vz = Arrow3D([xmax+e,xmax+e],[ymin-e,ymin-e],[zmin-e,zmin-e+1],
        mutation_scale=20, lw=1, arrowstyle="-|>", color=couleur_tour)
    ax.add_artist(vz)
    ax.text(xmax+e+.8, ymin-.8*e, zmin-e, 'x', color=couleur_tour,
        verticalalignment='center', horizontalalignment='center')
    ax.text(xmax+e, ymin-e+.8, zmin-1.2*e, 'y', color=couleur_tour,
        verticalalignment='center', horizontalalignment='center')
    ax.text(xmax+e, ymin-1.2*e, zmin-e+.8, 'z', color=couleur_tour,
        verticalalignment='center', horizontalalignment='center')
    ax.set_xlim(xmin-e, xmax+e)
    ax.set_ylim(ymin-e, ymax+e)
    ax.set_zlim(zmin-e, zmax+e)
    ax.azim = 34
    ax.elev = 20
    plt.axis('off')
    plt.draw()

def Velocities(dim, n):
    if dim == 1:
        Velocities_1D(n)
    elif dim == 2:
        Velocities_2D(n)
    elif dim == 3:
        Velocities_3D(n)
    else:
        print("error of dimension")
    plt.show()

(Source code)

Velocities(1, 3)
Velocities(2, 2)
Velocities(3, 1)
../../_images/Velocities_01_00.png

(png, pdf)

../../_images/Velocities_01_01.png

(png, pdf)

../../_images/Velocities_01_02.png

(png, pdf)

__init__(dim=None, num=None, vx=None, vy=None, vz=None)

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__([dim, num, vx, vy, vz])

Initialize self.

get_symmetric([axis])

return the symmetric velocity.

set_symmetric()

create the symetric velocity.

Attributes

v

velocity