pencil.diag.particle

Diagnostics for particles.

Submodules

• pencil.diag.particle.diffusion
• pencil.diag.particle.dispersion_and_drift
• pencil.diag.particle.gas_velco_at_particle_pos
• pencil.diag.particle.gas_velo_at_particle_pos

Classes

DiffusionData

DiffusionData -- holds diffusion data for particles.

Functions

diffusion([directions, trange, sim, OVERWRITE, quiet, ...])	Calculate particle diffusion via stalked particles: PSTALK
dispersion_and_drift([sim, OVERWRITE, GLOBAL, LOCAL, ...])	This calculates the dispersion (sigma) and drift (zeta) locally and globally
gas_velo_at_particle_pos([varfiles, sim, scheme, ...])	This script calulates the gas velocity at the particle position and stores this together

Package Contents

pencil.diag.particle.diffusion(directions=['x'], trange=[0, -1], sim='.', OVERWRITE=False, quiet=True, jump_distance=0.5, use_existing_pstalk_sav=False)

Calculate particle diffusion via stalked particles: PSTALK Therefore, it read PSTALK files from Pencil Code using IDL by using the IDL<->Python Bridge. It may be activated manually!

Generated DiffusionData object will be stored in:

sim.pc_datadir/particle/diffusion/<direction>_<t_start>:<t_end>

and be reloaded and returned if already existing and OVERWRITE=False!

Parameters:

• sim (-) –

  simulation object, but also simulations object or list of simulations or path of simulation,

  default =’.’

• for (- directions list or directions to calculate diffusion) – default =[‘x’]

• ['x' (e.g.) – default =[‘x’]

• 'y' – default =[‘x’]

• 'z'] – default =[‘x’]

:param : default =[‘x’] :param - trange range in code time for which diffusion shall be calc.: default =[0, -1] :param - jump_distance expressed in L_: half the domain size :type - jump_distance expressed in L_: x,y,z :param - OVERWRITE previously calculated diffusions shall be overwritten: default =False :param - quiet verbosity: :param default =False: :param - use_existing_pstalk_sav: use existing <sim.datadir>/data/pc/tmp/pstalk.sav for speed up

Returns:

diffusion object for simulation, if function is called for a set of simulations, a dictionary with all diffusion objects and simulation-name as key is returned

class pencil.diag.particle.DiffusionData(direction='x', trange=[0, -1], sim='.', OVERWRITE=False, quiet=True, jump_distance=0.5, use_existing_pstalk_sav=False)

Bases: object

DiffusionData – holds diffusion data for particles.

pencil.diag.particle.dispersion_and_drift(sim=False, OVERWRITE=False, GLOBAL=True, LOCAL=True, use_IDL=False, recalculate_gas_velo_at_particle_pos=False)

This calculates the dispersion (sigma) and drift (zeta) locally and globally by using the gas_velo_at_particle_pos script and dataset for all particles.

With sigma = sqrt( 1/N_par * sum_i^N_par( (v_par(i) - <v_par>)^2 ) ) and zeta = sqrt( 1/N_par * sum_i^N_par( (v_par(i) - u(xp_i))^2 ) )

Arg:

OVERWRITE: set to True to overwrite already calculated results

GLOBAL: Calculate drift and dispersion globally, i.e. whole simulation domain LOCAL: Calculate drift and dispersion locally, i.e. grid cell wise recalculate_gas_velo_at_particle_pos:

if the dataset shall be recalcualted

use_IDL: use backup solution of IDL script and sav files

returns True if successfull

pencil.diag.particle.gas_velo_at_particle_pos(varfiles='last4', sim=False, scheme='tsc', use_IDL=False, OVERWRITE=False)

This script calulates the gas velocity at the particle position and stores this together with particle position, containing grid cell idicies, particle velocities, and particle index in a gas_velo_at_particle_pos file.

Parameters:

• varfiles – specifiy varfiles for calculation, e.g. ‘last’, ‘first’, ‘all’, ‘VAR###’, ‘last4’, ‘first3’

• scheme – possible are: - ngp: nearest grid point - cic: cloud in cell - tsc: triangular shaped cloud

• OVERWRITE – set to True to overwrite already calculated results