Eulerian Advection Solver

[jbarr44]

Hi,

I'm just getting started with this library and am trying to get a basic 1D kinematic simulation running. One thing I'm missing is how to implement a 'solver' into the 'EulerianAdvection' dynamics. I assume this refers to a numerical integration scheme, but the documentation is not clear about what exact form the constructor is expecting. A name? A function? Would greatly appreciate clarification.

Thanks.

[slayoo]

Hello @jbarr44, thanks for giving PySDM a try!

The EulerianAdvection dynamic expects a callable:

PySDM/PySDM/dynamics/eulerian_advection.py

Lines 7 to 8 in 91d0307

	def __init__(self, solvers):
	self.solvers = solvers

PySDM/PySDM/dynamics/eulerian_advection.py

Line 23 in 91d0307

self.solvers()

In the Shipway_and_Hill_2012 1D kinematic example, an MPDATA_1D class is defined which uses the PyMPDATA package for integrating single-column advection of water vapour, and is used there as argument for EulerianAdvection ctor:

PySDM/examples/PySDM_examples/Shipway_and_Hill_2012/simulation.py

Lines 49 to 58 in 91d0307

	self.mpdata = MPDATA_1D(
	nz=settings.nz,
	dt=settings.dt,
	mpdata_settings=settings.mpdata_settings,
	advector_of_t=lambda t: settings.rho_times_w(t) * settings.dt / settings.dz,
	advectee_of_zZ_at_t0=lambda zZ: settings.water_vapour_mixing_ratio(
	zZ_to_z_above_reservoir(zZ)
	),
	g_factor_of_zZ=lambda zZ: settings.rhod(zZ_to_z_above_reservoir(zZ)),
	)

PySDM/examples/PySDM_examples/Shipway_and_Hill_2012/simulation.py

Line 82 in 91d0307

self.builder.add_dynamic(EulerianAdvection(self.mpdata))

Details here:
https://github.com/open-atmos/PySDM/blob/main/examples/PySDM_examples/Shipway_and_Hill_2012/mpdata_1d.py

HTH,
Sylwester