`gnome.weatherers.dissolution`¶

model dissolution process

Module Contents¶

Classes¶

Dissolution

Dissolution is still under development and not recommended for use.

Functions¶

printoptions(*args, **kwargs)

Attributes¶

pp

gnome.weatherers.dissolution.pp¶

gnome.weatherers.dissolution.printoptions(*args, **kwargs)¶

class gnome.weatherers.dissolution.Dissolution(waves=None, wind=None, **kwargs)¶

Bases: gnome.weatherers.Weatherer

Dissolution is still under development and not recommended for use.

Parameters:: waves – waves object for obtaining wave_height, etc. at a given time

_schema¶

_ref_as = 'dissolution'¶

_req_refs = ['waves', 'wind']¶

prepare_for_model_run(sc)¶: Add dissolution key to mass_balance if it doesn’t exist. - Assumes all spills have the same type of oil - let’s only define this the first time

prepare_for_model_step(sc, time_step, model_time)¶: Set/update arrays used by dispersion module for this timestep

initialize_data(sc, num_released)¶

initialize the newly released portions of our data arrays:

If on is False, then arrays should not be included - dont’ initialize

_initialize_k_ow(sc, num_released)¶

Initialize the molar averaged oil/water partition coefficient.

Actually, there is nothing to do to initialize our partition coefficient, as it is recalculated in dissolve_oil()

dissolve_oil(data, substance, **kwargs)¶

Here is where we calculate the dissolved oil. We will outline the steps as we go along, but off the top of my head:

recalculate the partition coefficient (K_ow)
droplet distribution per LE should be calculated by the natural dispersion process and saved in the data arrays before the dissolution weathering process.
for each LE:
Note

right now the natural dispersion process only calculates a single average droplet size. But we still treat it as an iterable.
- for each droplet size category:
  calculate the water phase transfer velocity (k_w)
  
  calculate the mass xfer rate coefficient (beta)
  
  calculate the water column time fraction (f_wc)
  
  calculate the mass dissolved during refloat period
- calculate the mass dissolved from the slick during the calm period.
the mass dissolved in the water column and the slick is summed per mass fraction (should only be aromatic fractions)
the sum of dissolved masses are compared to the existing mass fractions and adjusted to make sure we don’t dissolve more mass than exists in the mass fractions.

oil_avg_density(masses, densities)¶

oil_total_volume(masses, densities)¶

state_variable(masses, densities, arom_mask)¶

beta_coeff(k_w, K_ow, v_inert)¶

water_column_time_fraction(points, model_time, water_phase_xfer_velocity)¶

calm_between_wave_breaks(points, model_time, time_step, time_spent_in_wc=0.0)¶

oil_concentration(masses, densities)¶

droplet_subsurface_mass_xfer_rate(droplet_avg_size, k_w, oil_concentrations, partition_coeffs, arom_mask, total_volumes)¶

Here we are implementing something similar to equations

1.26: this should estimate the mass xfer rate in kg/s

Note

For this equation to work, we need to estimate the total surface area of all droplets, not just a single one
1.27: this should estimate the mass xfer rate per unit area in kg/(m^2 * s)
1.28: combines equations 1.26 and 1.27
1.29: estimates the surface area of a single droplet.

We return the mass xfer rate in units (kg/s)

Note

The Cohen equation (eq. 1.1, 1.27), I believe, is actually expressed in kg/(m^2 * hr). So we need to convert our time units.

Note

for now, we are receiving a single average droplet size, which we assume will account for 100% of the oil volume. In the future we will need to work with something like:

[(drop_size, vol_fraction, k_w_drop),
 ...
]

This is because each droplet bin will represent a fraction of the total oil volume (or mass?), and will have its own distinct rise velocity. oil_concentrations and partition coefficients will be the same regardless of droplet size.

slick_subsurface_mass_xfer_rate(points, model_time, oil_concentration, partition_coeff, slick_area, arom_mask)¶

Here we are implementing something similar to equation 1.21 of our dissolution document.

The Cohen equation (eq. 1.1), I believe, is actually expressed in kg/(m^2 * hr). So we need to convert our time units.