Class Drift

Create an instance of the Drift() class. Requires a radial grid, a grain size grid and a velocity function.

The function can also be given as an interpolator object.

The optional args and kwargs give the additional arguments for the drift function, which are ignored in case func is an interpolator object

Parameters:

• r (array) - The radial points (cm)
• a (array) - The grain size grid (cm)
• func (function) - The function that describes the drift profile. Can be given as an interpolator object.
• args (tuple) - Additional parameters passed to the functions when eval or diff are called.

  (default: [])

• kwargs (dict) - Additional keywords passed to the functions when eval or diff are called.

  (default: {})

Overrides: object.__init__

Calculate the average drift velocity as a function of radius, normalising with respect to the average grain size (requires the grain size distribution).

Parameters:

• r (float/array) - The radial points (cm). If None, the default r grid is used.

  (default: None)

• norm_type (str) - The weighting of normalisation for the average drift velocity:
  • collisional: Int(w*nd*a^2*da)/Int(nd*a^2*da)
  • dens: Int(w*nd*a^3*da)/Int(nd*a^3*da)
  • nd: Int(w*nd*da)/Int(nd*da)
  • a: Int(w*a*da)/Int(a*da)
  • standard: Int(w*da)/Int(da)

  (default: 'standard')

• nd (Distribution()) - The grain size distribution. Only needed when norm_type is dens or nd.

  (default: None)

• warn (bool) - Warn when extrapolation occurs.

  (default: 1)

Returns: array/float

The average drift velocity evaluated at r (cm/s). Array is reduced by one dimension since a drops out as variable.