def kochin_data_array(
results: Sequence[LinearPotentialFlowResult],
theta_range: Sequence[float],
**kwargs,
) -> xr.Dataset:
"""Compute the Kochin function for a list of results and fills a dataset.
.. seealso::
:meth:`~capytaine.post_pro.kochin.compute_kochin`
The present function is just a wrapper around :code:`compute_kochin`.
"""
records = pd.DataFrame([
dict(**result._asdict(), theta=theta, kochin=kochin)
for result in results for theta, kochin in zip(
theta_range.data, compute_kochin(result, theta_range, **kwargs))
])
kochin_data = {}
if 'wave_direction' in records.columns:
diffraction = _dataset_from_dataframe(
records[~records['wave_direction'].isnull()], ['kochin'],
dimensions=['omega', 'wave_direction', 'theta'],
optional_dims=['g', 'rho', 'body_name', 'water_depth'])
kochin_data['kochin_diffraction'] = diffraction['kochin']
if 'radiating_dof' in records.columns:
radiation = _dataset_from_dataframe(
records[~records['radiating_dof'].isnull()],
variables=['kochin'],
dimensions=['omega', 'radiating_dof', 'theta'],
optional_dims=['g', 'rho', 'body_name', 'water_depth'])
kochin_data['kochin'] = radiation['kochin']
return kochin_data
def test_floating_sphere_finite_depth():
"""Compare with Nemoh 2.0 for some cases of a heaving sphere at the free surface in finite depth."""
sphere = Sphere(radius=1.0, ntheta=3, nphi=12, clip_free_surface=True)
sphere.add_translation_dof(direction=(0, 0, 1), name="Heave")
# omega = 1, radiation
problem = RadiationProblem(body=sphere, omega=1.0, radiating_dof="Heave", sea_bottom=-10.0)
result = solver.solve(problem, keep_details=True)
assert np.isclose(result.added_masses["Heave"], 1740.6, atol=1e-3*sphere.volume*problem.rho)
assert np.isclose(result.radiation_dampings["Heave"], 380.46, atol=1e-3*sphere.volume*problem.rho)
kochin = compute_kochin(result, np.linspace(0, np.pi, 3))
assert np.allclose(kochin, np.roll(kochin, 1)) # The far field is the same in all directions.
assert np.isclose(kochin[0], -0.2267+3.49e-3j, rtol=1e-3)
# omega = 1, diffraction
problem = DiffractionProblem(body=sphere, omega=1.0, wave_direction=0.0, sea_bottom=-10.0)
result = solver.solve(problem)
assert np.isclose(result.forces["Heave"], 1749.4 * np.exp(-2.922j), rtol=1e-3)
# omega = 2, radiation
problem = RadiationProblem(body=sphere, omega=2.0, radiating_dof="Heave", sea_bottom=-10.0)
result = solver.solve(problem)
assert np.isclose(result.added_masses["Heave"], 1375.0, atol=1e-3*sphere.volume*problem.rho)
assert np.isclose(result.radiation_dampings["Heave"], 1418.0, atol=1e-3*sphere.volume*problem.rho)
# omega = 2, diffraction
problem = DiffractionProblem(body=sphere, omega=2.0, wave_direction=0.0, sea_bottom=-10.0)
result = solver.solve(problem)
assert np.isclose(result.forces["Heave"], 5872.8 * np.exp(-2.627j), rtol=1e-3)
def test_floating_sphere_finite_freq():
"""Compare with Nemoh 2.0 for some cases of a heaving sphere at the free surface in infinite depth."""
sphere = Sphere(radius=1.0, ntheta=3, nphi=12, clip_free_surface=True)
sphere.add_translation_dof(direction=(0, 0, 1), name="Heave")
# omega = 1, radiation
problem = RadiationProblem(body=sphere, omega=1.0, sea_bottom=-np.infty)
result = solver.solve(problem, keep_details=True)
assert np.isclose(result.added_masses["Heave"], 1819.6, atol=1e-3*sphere.volume*problem.rho)
assert np.isclose(result.radiation_dampings["Heave"], 379.39, atol=1e-3*sphere.volume*problem.rho)
# omega = 1, free surface
free_surface = FreeSurface(x_range=(-62.5, 62.5), nx=5, y_range=(-62.5, 62.5), ny=5)
eta = solver.get_free_surface_elevation(result, free_surface)
ref = np.array(
[[-0.4340802E-02-0.4742809E-03j, -0.7986111E-03+0.4840984E-02j, 0.2214827E-02+0.4700642E-02j, -0.7986111E-03+0.4840984E-02j, -0.4340803E-02-0.4742807E-03j],
[-0.7986111E-03+0.4840984E-02j, 0.5733187E-02-0.2179381E-02j, 0.9460892E-03-0.7079404E-02j, 0.5733186E-02-0.2179381E-02j, -0.7986110E-03+0.4840984E-02j],
[0.2214827E-02+0.4700643E-02j, 0.9460892E-03-0.7079403E-02j, -0.1381670E-01+0.6039315E-01j, 0.9460892E-03-0.7079405E-02j, 0.2214827E-02+0.4700643E-02j],
[-0.7986111E-03+0.4840984E-02j, 0.5733186E-02-0.2179381E-02j, 0.9460891E-03-0.7079404E-02j, 0.5733187E-02-0.2179380E-02j, -0.7986113E-03+0.4840984E-02j],
[-0.4340803E-02-0.4742807E-03j, -0.7986111E-03+0.4840984E-02j, 0.2214827E-02+0.4700643E-02j, -0.7986113E-03+0.4840983E-02j, -0.4340803E-02-0.4742809E-03j]]
)
assert np.allclose(eta.reshape((5, 5)), ref, rtol=1e-4)
# omega = 1, diffraction
problem = DiffractionProblem(body=sphere, omega=1.0, sea_bottom=-np.infty)
result = solver.solve(problem, keep_details=True)
assert np.isclose(result.forces["Heave"], 1834.9 * np.exp(-2.933j), rtol=1e-3)
# omega = 1, Kochin function of diffraction problem
kochin = compute_kochin(result, np.linspace(0, np.pi, 10))
ref_kochin = np.array([
0.20229*np.exp(-1.5872j), 0.20369*np.exp(-1.5871j),
0.20767*np.exp(-1.5868j), 0.21382*np.exp(-1.5863j),
0.22132*np.exp(-1.5857j), 0.22931*np.exp(-1.5852j),
0.23680*np.exp(-1.5847j), 0.24291*np.exp(-1.5843j),
0.24688*np.exp(-1.5841j), 0.24825*np.exp(-1.5840j),
])
assert np.allclose(kochin, ref_kochin, rtol=1e-3)
# omega = 2, radiation
problem = RadiationProblem(body=sphere, omega=2.0, sea_bottom=-np.infty)
result = solver.solve(problem)
assert np.isclose(result.added_masses["Heave"], 1369.3, atol=1e-3*sphere.volume*problem.rho)
assert np.isclose(result.radiation_dampings["Heave"], 1425.6, atol=1e-3*sphere.volume*problem.rho)
# omega = 2, diffraction
problem = DiffractionProblem(body=sphere, omega=2.0, sea_bottom=-np.infty)
result = solver.solve(problem)
assert np.isclose(result.forces["Heave"], 5846.6 * np.exp(-2.623j), rtol=1e-3)
def kochin_data_array(
results: Sequence[LinearPotentialFlowResult],
theta_range: Sequence[float],
**kwargs,
) -> xr.Dataset:
"""Compute the Kochin function for a list of results and fills a dataset.
.. seealso::
:meth:`~capytaine.post_pro.kochin.compute_kochin`
The present function is just a wrapper around :code:`compute_kochin`.
"""
records = pd.DataFrame([
dict(result.settings_dict, theta=theta, kochin=kochin)
for result in results for theta, kochin in zip(
theta_range.data, compute_kochin(result, theta_range, **kwargs))
])
ds = _dataset_from_dataframe(
records, ['kochin'],
dimensions=['omega', 'radiating_dof', 'theta'],
optional_dims=['g', 'rho', 'body_name', 'water_depth'])
return ds['kochin']