test_dupuit_percolator.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Tue Jun  4 16:26:31 2019

@author: gtucker
"""

from dupuit_percolator import GroundwaterDupuitPercolator
from landlab import RasterModelGrid
from numpy.testing import assert_equal
import numpy as np


def test_simple_water_table():
    """Test a one-node steady simulation.

    Notes
    -----
    The analytical solution for one interior cell with one open boundary is as
    follows. The incoming recharge must equal the outgoing discharge. The
    incoming recharge is R, and the surface area is 1 m2, so the incoming
    volume per unit time is R m/s x 1 m x 1 m. The outgoing discharge is equal
    to the conductivity, K (m/s), times the thickness at the boundary, Hb,
    times the hydraulic gradient, which in this case is (H - 0) / dx = H.
    The thickness at the boundary in this test is H/2. Therefore:

        K H^2 / 2 = R, or

        H = sqrt( 2 R / K ).

    With R = 10^-8 m/s and K = 10^-2 m/s, we should have

        H ~ 0.00141 m.
    """
    boundaries = {'top': 'closed',
                  'left': 'closed',
                  'bottom': 'closed'}
    rg = RasterModelGrid((3, 3), bc=boundaries)
    gdp = GroundwaterDupuitPercolator(rg, recharge_rate=1.0e-8,
                                      hydraulic_conductivity=0.01)
    for i in range(12):
        gdp.run_one_step(5.0e4)

    assert_equal(np.round(gdp.thickness[4], 5), 0.00141)

    # Re-instantiate to test the case when the necessary fields already exist
    gdp = GroundwaterDupuitPercolator(rg)