gnome.weatherers.dissolution

model dissolution process

Attributes

pp

Classes

Dissolution

Dissolution is still under development and not recommended for use.

Functions

printoptions(*args, **kwargs)

Module Contents

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

waves = None
wind = None
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

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.

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

weather_elements(sc, time_step, model_time)

weather elements over time_step