pencil.math.Helmholtz

Perform a Helmholtz decomposition on a vector field returning a pair of orthogonal vectors with zero divergence and zero curl respectively.

Functions

helmholtz_fft(tot_field, grid, params[, nghost, pot, ...])

helmholz_fft(field, grid, params)

Module Contents

pencil.math.Helmholtz.helmholtz_fft(tot_field, grid, params, nghost=3, pot=True, rot=True, lno_mean=False, nonperi_bc=None, field_scalar=[], s=None, quiet=True)

helmholz_fft(field, grid, params)

Creates the decomposition vector pair for the supplied vector field.

Parameters:

  • tot_field (ndarray) – Vector field of dimension [3, mz, my, mx], which is decomposed.

  • grid (obj) – Grid object with grid spacing dx, dy, dz.

  • params (obj) – Simulation Params object with domain dimensions Lx, Ly and Lz.

  • nghost (int) – Number of ghost zones to exclude from the fft.

  • lno_mean (float) – Exclude any mean flow from the decomposition - should drop anyway.

  • nonperi_bc (string) – String if not None with boundary condition label. How to apply the bc needs to be implemented as required.

  • field_scalar (ndarray) – Scalar field (density) as debug tool for energy comparison.

  • s (list of int) – List of three integers if not None for fft dimension. If none the dimension of the field [nz,ny,nx] is used.

Return type:

ndarray with decomposed field.