Exemple #1
0
def main():
  """Converts PETSc output to .vtk format."""
  # parse command-line
  args = read_inputs()
  print('[case-directory] {}'.format(args.case_directory))
  print('[variables] {}'.format(args.variables))

  # list of time-steps to post-process
  time_steps = ioPetIBM.get_time_steps(args.case_directory, args.time_steps)

  # read mesh grid
  grid = ioPetIBM.read_grid(args.case_directory)

  for time_step in time_steps:
    if 'velocity' in args.variables:
      velocity = ioPetIBM.read_velocity(args.case_directory, time_step, grid,
                                        periodic=args.periodic)
      # need to get velocity at cell-centers, not staggered arrangement
      velocity = interpolate_cell_centers(velocity)
      ioPetIBM.write_vtk(velocity, args.case_directory, time_step, 
                         name='velocity',
                         view=[args.bottom_left, args.top_right],
                         stride=args.stride)
    if 'pressure' in args.variables:
      pressure = ioPetIBM.read_pressure(args.case_directory, time_step, grid)
      ioPetIBM.write_vtk(pressure, args.case_directory, time_step,
                         name='pressure',
                         view=[args.bottom_left, args.top_right],
                         stride=args.stride)
 def compare_velocity(self):
     """Compares the velocity field node by node with a reference."""
     time_step = ioPetIBM.get_time_steps(self.directory)[-1]
     grid = ioPetIBM.read_grid(self.directory)
     velocity = ioPetIBM.read_velocity(self.directory,
                                       time_step,
                                       grid,
                                       periodic=self.periodic)
     grid = ioPetIBM.read_grid(self.reference)
     velocity_reference = ioPetIBM.read_velocity(self.reference,
                                                 time_step,
                                                 grid,
                                                 periodic=self.periodic)
     for i, component in enumerate(velocity):
         self.compare_arrays(component.x,
                             velocity_reference[i].x,
                             tag='velocity[{}]: x-nodes'.format(i))
         self.compare_arrays(component.y,
                             velocity_reference[i].y,
                             tag='velocity[{}]: y-nodes'.format(i))
         try:
             self.compare_arrays(component.z,
                                 velocity_reference[i].z,
                                 tag='velocity[{}]: z-nodes'.format(i))
         except:
             pass
         self.compare_arrays(component.values,
                             velocity_reference[i].values,
                             tag='velocity[{}]: values'.format(i))
Exemple #3
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def main(args):
  """
  Generates .vtk files out of the saved PETSc solutions.

  Parameters
  ----------
  args: namespace
    Databased with arguments parsed from the command-line.
  """
  print('[directory] {}'.format(args.directory))
  print('[variables] {}'.format(args.variables))

  # list of time-steps to post-process
  time_steps = ioPetIBM.get_time_steps(args.directory, args.time_steps)

  # read mesh grid
  grid = ioPetIBM.read_grid(args.directory)

  for time_step in time_steps:
    if 'velocity' in args.variables:
      velocity = ioPetIBM.read_velocity(args.directory, time_step, grid,
                                        periodic=args.periodic)
      # need to get velocity at cell-centers, not staggered arrangement
      velocity = interpolate_cell_centers(velocity)
      ioPetIBM.write_vtk(velocity, args.directory, time_step,
                         name='velocity',
                         view=[args.bottom_left, args.top_right],
                         stride=args.stride)
    if 'pressure' in args.variables:
      pressure = ioPetIBM.read_pressure(args.directory, time_step, grid)
      ioPetIBM.write_vtk(pressure, args.directory, time_step,
                         name='pressure',
                         view=[args.bottom_left, args.top_right],
                         stride=args.stride)
 def compare_pressure(self):
     """
 Compares the pressure field node by node with a reference.
 """
     time_step = ioPetIBM.get_time_steps(directory=self.directory)[-1]
     grid = ioPetIBM.read_grid(directory=self.directory)
     pressure = ioPetIBM.read_pressure(time_step,
                                       grid,
                                       directory=self.directory)
     grid = ioPetIBM.read_grid(directory=self.reference)
     pressure_reference = ioPetIBM.read_pressure(time_step,
                                                 grid,
                                                 directory=self.reference)
     self.compare_arrays(pressure.x,
                         pressure_reference.x,
                         tag='pressure: x-nodes')
     self.compare_arrays(pressure.y,
                         pressure_reference.y,
                         tag='pressure: y-nodes')
     try:
         self.compare_arrays(pressure.z,
                             pressure_reference.z,
                             tag='pressure: z-nodes')
     except:
         pass
     self.compare_arrays(pressure.values,
                         pressure_reference.values,
                         tag='pressure: values')
Exemple #5
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def main():
  """Plots the the velocity, pressure and vorticity fields at saved time-steps
  for a two-dimensional simulation.
  """
  # parse command-line
  args = read_inputs()
  print('[case directory] {}'.format(args.case_directory))

  time_steps = ioPetIBM.get_time_steps(args.case_directory, args.time_steps)
 
  # create directory where images will be saved
  images_directory = '{}/images'.format(args.case_directory)
  print('[images directory] {}'.format(images_directory))
  if not os.path.isdir(images_directory):
    os.makedirs(images_directory)

  # read the grid nodes
  coords = ioPetIBM.read_grid(args.case_directory)

  # load default style of matplotlib figures
  pyplot.style.use('{}/scripts/python/style/'
                   'style_PetIBM.mplstyle'.format(os.environ['PETIBM_DIR']))

  for time_step in time_steps:
    if args.velocity or args.vorticity:
      # get velocity fields
      u, v = ioPetIBM.read_velocity(args.case_directory, time_step, coords,
                                    periodic=args.periodic)
      if args.velocity:
        # plot u-velocity field
        u.label = 'u-velocity'
        image_path = '{}/uVelocity{:0>7}.png'.format(images_directory, time_step)
        plot_contour(u, args.u_range, image_path, 
                     view=args.bottom_left+args.top_right,
                   size=args.size, dpi=args.dpi)
        # plot v-velocity field
        v.label = 'v-velocity'
        image_path = '{}/vVelocity{:0>7}.png'.format(images_directory, time_step)
        plot_contour(v, args.v_range, image_path, 
                     view=args.bottom_left+args.top_right,
                   size=args.size, dpi=args.dpi)
      if args.vorticity:
        # compute vorticity field
        w = vorticity(u, v)
        # plot vorticity field
        w.label = 'vorticity'
        image_path = '{}/vorticity{:0>7}.png'.format(images_directory, time_step)
        plot_contour(w, args.vorticity_range, image_path, 
                     view=args.bottom_left+args.top_right,
                   size=args.size, dpi=args.dpi)
    if args.pressure:
      # get pressure field
      p = ioPetIBM.read_pressure(args.case_directory, time_step, coords)
      # plot pressure field
      p.label = 'pressure'
      image_path = '{}/pressure{:0>7}.png'.format(images_directory, time_step)
      plot_contour(p, args.pressure_range, image_path, 
                   view=args.bottom_left+args.top_right,
                   size=args.size, dpi=args.dpi)
 def compare_pressure(self):
   """Compares the pressure field node by node with a reference."""
   time_step = ioPetIBM.get_time_steps(self.directory)[-1]
   grid = ioPetIBM.read_grid(self.directory)
   pressure = ioPetIBM.read_pressure(self.directory, time_step, grid)
   grid = ioPetIBM.read_grid(self.reference)
   pressure_reference = ioPetIBM.read_pressure(self.reference, time_step, grid)
   self.compare_arrays(pressure.x, pressure_reference.x, 
                       tag='pressure: x-nodes')
   self.compare_arrays(pressure.y, pressure_reference.y, 
                       tag='pressure: y-nodes')
   try:
     self.compare_arrays(pressure.z, pressure_reference.z, 
                         tag='pressure: z-nodes')
   except:
     pass
   self.compare_arrays(pressure.values, pressure_reference.values, 
                       tag='pressure: values')
 def compare_velocity(self):
   """Compares the velocity field node by node with a reference."""
   time_step = ioPetIBM.get_time_steps(self.directory)[-1]
   grid = ioPetIBM.read_grid(self.directory)
   velocity = ioPetIBM.read_velocity(self.directory, time_step, grid, 
                                     periodic=self.periodic)
   grid = ioPetIBM.read_grid(self.reference)
   velocity_reference = ioPetIBM.read_velocity(self.reference, time_step, grid, 
                                               periodic=self.periodic)
   for i, component in enumerate(velocity):
     self.compare_arrays(component.x, velocity_reference[i].x, 
                         tag='velocity[{}]: x-nodes'.format(i))
     self.compare_arrays(component.y, velocity_reference[i].y, 
                         tag='velocity[{}]: y-nodes'.format(i))
     try:
       self.compare_arrays(component.z, velocity_reference[i].z, 
                           tag='velocity[{}]: z-nodes'.format(i))
     except:
       pass
     self.compare_arrays(component.values, velocity_reference[i].values, 
                         tag='velocity[{}]: values'.format(i))
Exemple #8
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def main():
    """Converts PETSc output to .vtk format."""
    # parse command-line
    args = read_inputs()
    print('[case-directory] {}'.format(args.case_directory))
    print('[variables] {}'.format(args.variables))

    # list of time-steps to post-process
    time_steps = ioPetIBM.get_time_steps(args.case_directory, args.time_steps)

    # read mesh grid
    grid = ioPetIBM.read_grid(args.case_directory)

    for time_step in time_steps:
        if 'velocity' in args.variables:
            velocity = ioPetIBM.read_velocity(args.case_directory,
                                              time_step,
                                              grid,
                                              periodic=args.periodic)
            # need to get velocity at cell-centers, not staggered arrangement
            velocity = interpolate_cell_centers(velocity)
            ioPetIBM.write_vtk(velocity,
                               args.case_directory,
                               time_step,
                               name='velocity',
                               view=[args.bottom_left, args.top_right],
                               stride=args.stride)
        if 'pressure' in args.variables:
            pressure = ioPetIBM.read_pressure(args.case_directory, time_step,
                                              grid)
            ioPetIBM.write_vtk(pressure,
                               args.case_directory,
                               time_step,
                               name='pressure',
                               view=[args.bottom_left, args.top_right],
                               stride=args.stride)
Exemple #9
0
def main(args):
    """
  Plots and writes the velocity components at the centerline of the cavity
  and compares with experimental results form Ghia et al. (1982).

  Parameters
  ----------
  args: namespace
    Database with arguments parsed from the command-line.
  """
    # column indices in file with experimental results
    cols = {
        '100': {
            'u': 1,
            'v': 7
        },
        '1000': {
            'u': 2,
            'v': 8
        },
        '3200': {
            'u': 3,
            'v': 9
        },
        '5000': {
            'u': 4,
            'v': 10
        },
        '10000': {
            'u': 5,
            'v': 11
        }
    }
    experimental_file = os.path.join(
        os.path.dirname(os.path.realpath(__file__)), 'data',
        'cavity-GGS82.txt')

    print('[case directory] {}'.format(args.directory))
    Re = args.Re

    if not args.time_step:
        args.time_step = ioPetIBM.get_time_steps(directory=args.directory)[-1]

    # read mesh grid
    grid = ioPetIBM.read_grid(directory=args.directory)
    nx, ny = grid[0].size - 1, grid[1].size - 1

    # create directory where images will be saved
    images_directory = os.path.join(args.directory, 'images')
    print('[images directory] {}'.format(images_directory))
    if not os.path.isdir(images_directory):
        os.makedirs(images_directory)

    # create directory where data will be saved
    data_directory = os.path.join(args.directory, 'data')
    print('[data directory] {}'.format(data_directory))
    if not os.path.isdir(data_directory):
        os.makedirs(data_directory)

    # get velocity field
    u, v = ioPetIBM.read_velocity(args.time_step,
                                  grid,
                                  directory=args.directory)

    # load default style for figures
    pyplot.style.use(
        os.path.join(os.environ['PETIBM_DIR'], 'scripts', 'python', 'style',
                     'style_PetIBM.mplstyle'))

    # plot and write u-velocity along y-centerline
    print('\nPlot u-velocity along vertical centerline ...')
    pyplot.grid(True)
    pyplot.xlabel('y', )
    pyplot.ylabel('u-velocity along vertical centerline')
    if nx % 2 == 0:
        u_centerline = u.values[:, nx / 2 - 1]
    else:
        u_centerline = 0.5 * (u.values[:, nx / 2 - 1] + u.values[:, nx / 2])
    pyplot.plot(u.y,
                u_centerline,
                label='PetIBM',
                color='k',
                linestyle='-',
                linewidth=1)
    if Re in list(cols.keys()):
        print('\nComparison with Ghia et al. (1982)')
        with open(experimental_file, 'r') as infile:
            y_exp, u_exp = numpy.loadtxt(infile,
                                         dtype=float,
                                         usecols=(0, cols[Re]['u']),
                                         unpack=True)
        pyplot.plot(y_exp,
                    u_exp,
                    label='Ghia et al. (1982)',
                    linewidth=0,
                    marker='o')
    pyplot.legend()
    pyplot.title('Lid-driven cavity flow at Re={} (mesh: {}x{})'
                 ''.format(Re, nx, ny))
    pyplot.savefig(
        os.path.join(images_directory,
                     'uVelocityCenterlineRe{}_{}x{}.png'.format(Re, nx, ny)))
    pyplot.close()
    print('\nWrite u-velocity along vertical centerline ...')
    data_path = os.path.join(
        data_directory, 'uVelocityCenterlineRe{}_{}x{}.txt'.format(Re, nx, ny))
    with open(data_path, 'w') as outfile:
        numpy.savetxt(outfile,
                      numpy.c_[u.y, u_centerline],
                      fmt='%.6f',
                      delimiter='\t',
                      header='u-velocity along vertical centerline\n'
                      'Re={}, mesh: {}x{}\n[y]\t[u]'.format(Re, nx, ny))

    # plot and write v-velocity along x-centerline
    print('\nPlot v-velocity along horizontal centerline ...')
    pyplot.grid(True)
    pyplot.xlabel('x')
    pyplot.ylabel('v-velocity along horizontal centerline')
    if ny % 2 == 0:
        v_centerline = v.values[ny / 2 - 1, :]
    else:
        v_centerline = 0.5 * (v.values[ny / 2 - 1, :] + v.values[ny / 2, :])
    pyplot.plot(v.x,
                v_centerline,
                label='PetIBM',
                color='k',
                linestyle='-',
                linewidth=1)
    if Re in list(cols.keys()):
        print('Comparison with Ghia et al. (1982)')
        with open(experimental_file, 'r') as infile:
            x_exp, u_exp = numpy.loadtxt(infile,
                                         dtype=float,
                                         usecols=(6, cols[Re]['v']),
                                         unpack=True)
        pyplot.plot(x_exp,
                    u_exp,
                    label='Ghia et al. (1982)',
                    linewidth=0,
                    marker='o')
    pyplot.legend()
    pyplot.title('Lid-driven cavity flow at Re={} (mesh: {}x{})'
                 ''.format(Re, nx, ny))
    pyplot.savefig(
        os.path.join(images_directory,
                     'vVelocityCenterlineRe{}_{}x{}.png'.format(Re, nx, ny)))
    pyplot.close()
    print('\nwrite v-velocity along horizontal centerline ...')
    data_path = os.path.join(
        data_directory, 'vVelocityCenterlineRe{}_{}x{}.txt'.format(Re, nx, ny))
    with open(data_path, 'w') as outfile:
        numpy.savetxt(outfile,
                      numpy.c_[v.x, v_centerline],
                      fmt='%.6f',
                      delimiter='\t',
                      header='v-velocity along horizontal centerline\n'
                      'Re={}, mesh: {}x{}\n[x]\t[v]'.format(Re, nx, ny))
Exemple #10
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def main():
  """Plots and writes the velocity components at the centerline of the cavity
  and compares with experimental results form Ghia et al. (1982).
  """
  # column indices in file with experimental results
  cols = {'100': {'u': 1, 'v': 7},
          '1000': {'u':2, 'v': 8},
          '3200': {'u':3, 'v': 9},
          '5000': {'u':4, 'v': 10},
          '10000': {'u': 5, 'v': 11}}
  experimental_file = ('{}/validation_data/'
                       'cavity-GGS82.txt'.format(os.environ['PETIBM_DIR']))

  # parse command-line
  args = read_inputs()
  print('[case directory] {}'.format(args.case_directory))
  Re = args.Re

  if not args.time_step:
    args.time_step = ioPetIBM.get_time_steps(args.case_directory)[-1]

  # read mesh grid
  grid = ioPetIBM.read_grid(args.case_directory)
  nx, ny = grid[0].size-1, grid[1].size-1

  # create directory where images will be saved
  images_directory = '{}/images'.format(args.case_directory)
  print('[images directory] {}'.format(images_directory))
  if not os.path.isdir(images_directory):
    os.makedirs(images_directory)

  # create directory where data will be saved
  data_directory = '{}/data'.format(args.case_directory)
  print('[data directory] {}'.format(data_directory))
  if not os.path.isdir(data_directory):
    os.makedirs(data_directory)

  # get velocity field
  u, v = ioPetIBM.read_velocity(args.case_directory, args.time_step, grid)

  # load default style for figures
  pyplot.style.use('{}/scripts/python/style/'
                   'style_PetIBM.mplstyle'.format(os.environ['PETIBM_DIR']))

  # plot and write u-velocity along y-centerline
  print('\nPlot u-velocity along vertical centerline ...')
  pyplot.xlabel('y',)
  pyplot.ylabel('u-velocity along vertical centerline')
  if nx%2 == 0:
    u_centerline = u.values[:, nx/2-1]
  else:
    u_centerline = 0.5*(u.values[:, nx/2-1]+u.values[:, nx/2])
  pyplot.plot(u.y, u_centerline, label='PetIBM', 
              color='k', linestyle='-', linewidth=1)
  if Re in list(cols.keys()):
    print('\nComparison with Ghia et al. (1982)')
    with open(experimental_file, 'r') as infile:
      y_exp, u_exp = numpy.loadtxt(infile, dtype=float, 
                                   usecols= (0, cols[Re]['u']), unpack=True)
    pyplot.plot(y_exp, u_exp, label='Ghia et al. (1982)', 
                linewidth=0, marker='o')
  pyplot.legend()
  pyplot.title('Lid-driven cavity flow at Re={} (mesh: {}x{})'.format(Re, nx, ny))
  pyplot.savefig('{}/uVelocityCenterlineRe{}_{}x{}.png'.format(images_directory, 
                                                               Re, nx, ny))
  pyplot.close()
  print('\nWrite u-velocity along vertical centerline ...')
  data_path = '{}/uVelocityCenterlineRe{}_{}x{}.txt'.format(data_directory, 
                                                            Re, nx, ny)
  with open(data_path, 'w') as outfile:
    numpy.savetxt(outfile, numpy.c_[u.y, u_centerline], 
                  fmt='%.6f', delimiter='\t',
                  header='u-velocity along vertical centerline\n'
                         'Re={}, mesh: {}x{}\n[y]\t[u]'.format(Re, nx, ny))

  # plot and write v-velocity along x-centerline
  print('\nPlot v-velocity along horizontal centerline ...')
  pyplot.xlabel('x')
  pyplot.ylabel('v-velocity along horizontal centerline')
  if ny%2 == 0:
    v_centerline = v.values[ny/2-1, :]
  else:
    v_centerline = 0.5*(v.values[ny/2-1, :]+v.values[ny/2, :])
  pyplot.plot(v.x, v_centerline, label='PetIBM', 
              color='k', linestyle='-', linewidth=1)
  if Re in list(cols.keys()):
    print('Comparison with Ghia et al. (1982)')
    with open(experimental_file, 'r') as infile:
      x_exp, u_exp = numpy.loadtxt(infile, dtype=float, 
                                   usecols= (6, cols[Re]['v']), unpack=True)
    pyplot.plot(x_exp, u_exp, label='Ghia et al. (1982)', 
                linewidth=0, marker='o')
  pyplot.legend()
  pyplot.title('Lid-driven cavity flow at Re={} (mesh: {}x{})'.format(Re, nx, ny))
  pyplot.savefig('{}/vVelocityCenterlineRe{}_{}x{}.png'.format(images_directory, 
                                                               Re, nx, ny))
  pyplot.close()
  print('\nwrite v-velocity along horizontal centerline ...')
  data_path = '{}/vVelocityCenterlineRe{}_{}x{}.txt'.format(data_directory, 
                                                            Re, nx, ny)
  with open(data_path, 'w') as outfile:
    numpy.savetxt(outfile, numpy.c_[v.x, v_centerline], 
                  fmt='%.6f', delimiter='\t',
                  header='v-velocity along horizontal centerline\n'
                         'Re={}, mesh: {}x{}\n[x]\t[v]'.format(Re, nx, ny))
Exemple #11
0
def main():
    """Plots the the velocity, pressure and vorticity fields at saved time-steps
  for a two-dimensional simulation.
  """
    # parse command-line
    args = read_inputs()
    print('[case directory] {}'.format(args.case_directory))

    time_steps = ioPetIBM.get_time_steps(args.case_directory, args.time_steps)

    # create directory where images will be saved
    images_directory = '{}/images'.format(args.case_directory)
    print('[images directory] {}'.format(images_directory))
    if not os.path.isdir(images_directory):
        os.makedirs(images_directory)

    # read the grid nodes
    coords = ioPetIBM.read_grid(args.case_directory)

    # load default style of matplotlib figures
    pyplot.style.use('{}/scripts/python/style/'
                     'style_PetIBM.mplstyle'.format(os.environ['PETIBM_DIR']))

    for time_step in time_steps:
        if args.velocity or args.vorticity:
            # get velocity fields
            u, v = ioPetIBM.read_velocity(args.case_directory,
                                          time_step,
                                          coords,
                                          periodic=args.periodic)
            if args.velocity:
                # plot u-velocity field
                u.label = 'u-velocity'
                image_path = '{}/uVelocity{:0>7}.png'.format(
                    images_directory, time_step)
                plot_contour(u,
                             args.u_range,
                             image_path,
                             view=args.bottom_left + args.top_right,
                             size=args.size,
                             dpi=args.dpi)
                # plot v-velocity field
                v.label = 'v-velocity'
                image_path = '{}/vVelocity{:0>7}.png'.format(
                    images_directory, time_step)
                plot_contour(v,
                             args.v_range,
                             image_path,
                             view=args.bottom_left + args.top_right,
                             size=args.size,
                             dpi=args.dpi)
            if args.vorticity:
                # compute vorticity field
                w = vorticity(u, v)
                # plot vorticity field
                w.label = 'vorticity'
                image_path = '{}/vorticity{:0>7}.png'.format(
                    images_directory, time_step)
                plot_contour(w,
                             args.vorticity_range,
                             image_path,
                             view=args.bottom_left + args.top_right,
                             size=args.size,
                             dpi=args.dpi)
        if args.pressure:
            # get pressure field
            p = ioPetIBM.read_pressure(args.case_directory, time_step, coords)
            # plot pressure field
            p.label = 'pressure'
            image_path = '{}/pressure{:0>7}.png'.format(
                images_directory, time_step)
            plot_contour(p,
                         args.pressure_range,
                         image_path,
                         view=args.bottom_left + args.top_right,
                         size=args.size,
                         dpi=args.dpi)
Exemple #12
0
def main(args):
    """
  Plots the the velocity, pressure and vorticity fields at saved time-steps
  for a two-dimensional simulation.

  Parameters
  ----------
  args: namespace
    Database with arguments parsed from the command-line.
  """
    print('[case directory] {}'.format(args.directory))

    time_steps = ioPetIBM.get_time_steps(args.time_steps,
                                         directory=args.directory)

    # create directory where images will be saved
    images_directory = os.path.join(args.directory, 'images')
    print('[images directory] {}'.format(images_directory))
    if not os.path.isdir(images_directory):
        os.makedirs(images_directory)

    # read the grid nodes
    coords = ioPetIBM.read_grid(directory=args.directory)

    # load default style of matplotlib figures
    pyplot.style.use(
        os.path.join(os.environ['PETIBM_DIR'], 'scripts', 'python', 'style',
                     'style_PetIBM.mplstyle'))

    for time_step in time_steps:
        if args.velocity or args.vorticity:
            # get velocity fields
            u, v = ioPetIBM.read_velocity(time_step,
                                          coords,
                                          directory=args.directory,
                                          periodic=args.periodic)
            if args.velocity:
                # plot u-velocity field
                u.label = 'u-velocity'
                image_path = os.path.join(
                    images_directory, 'uVelocity{:0>7}.png'.format(time_step))
                plot_contour(u,
                             args.u_range,
                             image_path,
                             view=args.bottom_left + args.top_right,
                             size=args.size,
                             dpi=args.dpi)
                # plot v-velocity field
                v.label = 'v-velocity'
                image_path = os.path.join(
                    images_directory, 'vVelocity{:0>7}.png'.format(time_step))
                plot_contour(v,
                             args.v_range,
                             image_path,
                             view=args.bottom_left + args.top_right,
                             size=args.size,
                             dpi=args.dpi)
            if args.vorticity:
                # compute vorticity field
                w = vorticity(u, v)
                # plot vorticity field
                w.label = 'vorticity'
                image_path = os.path.join(
                    images_directory, 'vorticity{:0>7}.png'.format(time_step))
                plot_contour(w,
                             args.vorticity_range,
                             image_path,
                             view=args.bottom_left + args.top_right,
                             size=args.size,
                             dpi=args.dpi)
        if args.pressure:
            # get pressure field
            p = ioPetIBM.read_pressure(time_step,
                                       coords,
                                       directory=args.directory)
            # plot pressure field
            p.label = 'pressure'
            image_path = os.path.join(images_directory,
                                      'pressure{:0>7}.png'.format(time_step))
            plot_contour(p,
                         args.pressure_range,
                         image_path,
                         view=args.bottom_left + args.top_right,
                         size=args.size,
                         dpi=args.dpi)