def dissolve_oil(self, 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)
TODO: This requires a molar average of the aromatic components.
- use VDROP to calculate the shift in the droplet distribution
- for each droplet size category:
- calculate the water phase transfer velocity (k_w) (Stokes)
- calculate the mass xfer rate coefficient (beta)
- calculate the water column time fraction (f_wc)
- calculate the volume dissolved
- subtract the mass of smallest droplets in our distribution
that are below a threshold.
'''
fmass = data['mass_components']
arom_mask = substance._sara['type'] == 'Aromatics'
mol_wt = substance.molecular_weight
rho = substance.component_density
assert mol_wt.shape == rho.shape
# calculate the partition coefficient (K_ow) for all aromatics.
# K_ow for non-aromatics should be masked to 0.0
K_ow_comp = arom_mask * LeeHuibers.partition_coeff(mol_wt, rho)
for idx, m in enumerate(fmass):
K_ow = (np.sum(m * K_ow_comp / mol_wt) /
np.sum(m / mol_wt))
data['partition_coeff'][idx] = K_ow
diss = np.zeros((len(data['mass'])), dtype=np.float64)
return diss
def test_lee_huibers():
assert np.isclose(LeeHuibers.partition_coeff(92.1, 866.0), 1000)
def test_lee_huibers():
assert np.isclose(LeeHuibers.partition_coeff(92.1, 866.0), 1000)
def dissolve_oil(self, 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.
'''
model_time = kwargs.get('model_time')
time_step = kwargs.get('time_step')
fmasses = data['mass_components']
droplet_avg_sizes = data['droplet_avg_size']
areas = data['area']
arom_mask = substance._sara['type'] == 'Aromatics'
mol_wt = substance.molecular_weight
rho = substance.component_density
assert mol_wt.shape == rho.shape
# calculate the partition coefficient (K_ow) for all aromatics
# for each LE.
# K_ow for non-aromatics are masked to 0.0
K_ow_comp = arom_mask * LeeHuibers.partition_coeff(mol_wt, rho)
data['partition_coeff'] = ((fmasses * K_ow_comp / mol_wt).sum(axis=1) /
(fmasses / mol_wt).sum(axis=1))
avg_rhos = self.oil_avg_density(fmasses, rho)
water_rhos = np.zeros(avg_rhos.shape) + self.waves.water.get('density')
k_w_i = Stokes.water_phase_xfer_velocity(water_rhos - avg_rhos,
droplet_avg_sizes)
total_volumes = self.oil_total_volume(fmasses, rho)
X_i, S_RA_volumes = self.state_variable(fmasses, rho, arom_mask)
beta_i = self.beta_coeff(k_w_i, data['partition_coeff'], S_RA_volumes)
dX_dt_i = beta_i * X_i / (X_i + 1.0) ** (1.0 / 3.0)
f_wc_i = self.water_column_time_fraction(model_time, k_w_i)
T_wc_i = f_wc_i * time_step
T_calm_i = self.calm_between_wave_breaks(model_time, time_step, T_wc_i)
assert np.alltrue(T_calm_i <= float(time_step))
assert np.alltrue(T_wc_i <= float(time_step))
assert np.alltrue(T_wc_i + T_calm_i <= float(time_step))
aromatic_masses_i = fmasses * arom_mask
aromatic_fractions_i = (aromatic_masses_i.T /
aromatic_masses_i.sum(axis=1)).T
#
# OK, here it is, the mass dissolved in the water column.
#
mass_dissolved_in_wc = np.nan_to_num((aromatic_fractions_i.T *
dX_dt_i * T_wc_i).T)
oil_concentrations = self.oil_concentration(fmasses, rho)
N_s_i = self.slick_subsurface_mass_xfer_rate(model_time,
oil_concentrations,
K_ow_comp,
areas,
arom_mask)
#
# OK, here it is, the mass dissolved in the slick.
#
mass_dissolved_in_slick = (N_s_i.T * T_calm_i).T
mass_dissolved_in_wc = np.vstack(mass_dissolved_in_wc)
mass_dissolved_in_slick = np.vstack(mass_dissolved_in_slick)
total_mass_dissolved = mass_dissolved_in_wc + mass_dissolved_in_slick
# adjust any masses that might go negative
total_mass_dissolved += np.clip(fmasses - total_mass_dissolved,
-np.inf, 0.0)
return total_mass_dissolved