.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "auto_examples/nonhydro/tracers_and_eddies.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code. .. rst-class:: sphx-glr-example-title .. _sphx_glr_auto_examples_nonhydro_tracers_and_eddies.py: Tracers and Eddies ================== Adding passive tracers to the model. Experiment 1 ------------ A passive tracer forms a spiral pattern when advected by an eddy. .. video:: videos/tracer_and_eddies_spiral.mp4 Experiment 2 ------------ An eddy-dipole collides with a tracer band. .. video:: videos/tracer_and_eddies_dipole.mp4 .. GENERATED FROM PYTHON SOURCE LINES 20-184 .. code-block:: Python import fridom.nonhydro as nh import os import matplotlib.pyplot as plt ncp = nh.config.ncp # ---------------------------------------------------------------- # Experiment settings # ---------------------------------------------------------------- # General settings make_video = True make_netcdf = False fps = 30 exp_name = "tracer_and_eddies" thumbnail = f"figures/{exp_name}.png" # Physical parameters f0 = 1.0 # Coriolis parameter N0 = 1.0 # Brunt-Väisälä frequency Lx = 1.0 # non-dimensional domain size in x and y # Numerical parameters periodic = (True, True, True) # periodic in y and z, non-periodic in x resolution_factor = 10 # 2^10 = 1024 grid points Nx = 2**(resolution_factor) # Number of grid points in x and y # ---------------------------------------------------------------- # Create a plotting module for the animation and thumbnail # ---------------------------------------------------------------- def create_plotter(skip): class Plotter(nh.modules.animation.ModelPlotter): def create_figure(): return plt.figure(figsize=(6, 4.5), dpi=256, tight_layout=True) def prepare_arguments(mz: nh.ModelState) -> dict: return {"z": mz.z.xrs[::skip,::skip,0], "tracer": mz.z['dye'].xrs[:,:,0], "t": mz.clock.time} def update_figure(fig, z, tracer, t) -> None: ax = fig.add_subplot(111) tracer.plot(ax=ax, cmap="Blues", vmax=1.0, vmin=0, extend='max') key = z.plot.quiver("x", "y", "u", "v", scale=30, add_guide=False, color="black", width=0.003, headwidth=3) label_velo = 2 ax.quiverkey(key, X=0.9, Y=1.05, U=label_velo, label=f'{label_velo} [m/s]', labelpos='E') ax.set_aspect('equal') ax.set_title(f't={t:.3f}s', fontsize=18) return Plotter # ---------------------------------------------------------------- # Create the grid and model settings # ---------------------------------------------------------------- def create_modelsettings(exp_name, quiver_skip): grid = nh.grid.cartesian.Grid( L=(Lx, Lx, Lx), N=(Nx, Nx, 1), periodic_bounds=periodic) mset = nh.ModelSettings(grid=grid, f0=f0, N2=N0**2) mset.time_stepper.dt = 0.4 * 1/Nx # add the passive tracer to the state vector mset.add_field_to_state({'name':"dye", 'long_name':"Dye concentration", "flags": {'ENABLE_MIXING': True}}) # ---------------------------------------------------------------- # Add custom modules to the model settings # ---------------------------------------------------------------- # add a video writer if make_video: mset.diagnostics.add_module(nh.modules.animation.VideoWriter( create_plotter(quiver_skip), model_time_per_second=0.5, filename=exp_name, fps=30)) # create a NetCDF writer to save the output if make_netcdf: mset.diagnostics.add_module(nh.modules.NetCDFWriter( get_variables=lambda mz: [mz.z['dye'], mz.z.cfl], write_interval = 0.1, filename=exp_name)) # add mixing for the tracer # mset.tendencies.add_module(nh.modules.closures.HarmonicMixing( # kh=0.1*(Lx/Nx)**3, kv=0)) mset.setup() return mset # ================================================================ # Experiment 1: Spiral pattern # ================================================================ @nh.utils.skip_on_doc_build def experiment_1(): mset = create_modelsettings(exp_name + "_spiral", quiver_skip=40) # ---------------------------------------------------------------- # Create the initial condition # ---------------------------------------------------------------- z_ini = nh.initial_conditions.CoherentEddy( mset=mset, pos_x=0.5, pos_y=0.5, width=0.2, gauss_field="vorticity") z_ini *= 1 / ((z_ini.u**2 + z_ini.v**2)**0.5).max() # add the passive tracer X, Y, Z = z_ini["dye"].get_mesh() band_width = 0.05 # z_ini['dye'] += ( (Y < 0.5 + band_width/2) & (Y > 0.5 - band_width/2) ) * 1.0 z_ini['dye'] += ncp.exp(-((Y-0.5)/band_width)**2) # ---------------------------------------------------------------- # Create and run the model # ---------------------------------------------------------------- model = nh.Model(mset) model.z = z_ini model.run(runlen=1.5) # plot the final state (thumbnail) os.makedirs("figures", exist_ok=True) fig = create_plotter(40)(model.model_state) fig.savefig(thumbnail, dpi=200) # ================================================================ # Experiment 2: Eddy-dipole # ================================================================ @nh.utils.skip_on_doc_build def experiment_2(): mset = create_modelsettings(exp_name + "_dipole", quiver_skip=20) # ---------------------------------------------------------------- # Create the initial condition # ---------------------------------------------------------------- L_eddy = 0.05 def create_dipole(pos_x, pos_y): z_eddy = nh.initial_conditions.CoherentEddy( mset=mset, pos_x=pos_x-L_eddy/Lx, pos_y=pos_y, width=L_eddy, gauss_field="vorticity") z_eddy -= nh.initial_conditions.CoherentEddy( mset=mset, pos_x=pos_x+L_eddy/Lx, pos_y=pos_y, width=L_eddy, gauss_field="vorticity") z_eddy *= 1 / ((z_eddy.u**2 + z_eddy.v**2)**0.5).max() return z_eddy z_ini = create_dipole(0.5, 0.3) # add the passive tracer X, Y, Z = z_ini["dye"].get_mesh() band_width = 0.05 z_ini['dye'] += ncp.exp(-((Y-0.75)/band_width)**2) # ---------------------------------------------------------------- # Create and run the model # ---------------------------------------------------------------- model = nh.Model(mset) model.z = z_ini model.run(runlen=5) if __name__ == "__main__": experiment_1() experiment_2() .. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 1.487 seconds) .. _sphx_glr_download_auto_examples_nonhydro_tracers_and_eddies.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: tracers_and_eddies.py ` .. container:: sphx-glr-download sphx-glr-download-zip :download:`Download zipped: tracers_and_eddies.zip `