Issue on appveyor - fluid_flow

[raphaeltimbo]

As mentioned by @rodrigomoliveira1, we are having the following issue on appveyor:

================================== FAILURES ===================================
_______________________ test_stiffness_matrix_numerical _______________________
    def test_stiffness_matrix_numerical():
        """
        This function instantiate a bearing using the fluid flow class and test if it matches the
        expected results for the stiffness matrix based on Friswell's book formulas, given the
        eccentricity ratio.
        Taken from chapter 5, page 179 (Dynamics of rotating machine, FRISSWELL)
        """
        bearing = fluid_flow_short_eccentricity()
        bearing.calculate_pressure_matrix_numerical()
        kxx, kxy, kyx, kyy = calculate_stiffness_matrix(bearing)
        k_xx, k_xy, k_yx, k_yy = calculate_analytical_stiffness_matrix(bearing.load,
                                                                       bearing.eccentricity_ratio,
                                                                       bearing.radial_clearance)
>       assert_allclose(kxx, k_xx, rtol=0.03)
E       AssertionError: 
E       Not equal to tolerance rtol=0.03, atol=0
E       
E       Mismatch: 100%
E       Max absolute difference: 1832798.36965361
E       Max relative difference: 3.78983434
E        x: array(-1349189.270584)
E        y: array(483609.09907)
tests\test_fluid_flow.py:106: AssertionError

The problem is that this error does not occur on all builds. I have taken this example from here.

[ross-bott]

Hi there! I have marked this issue as stale because it has not had activity for 45 days. Consider the following options:

• If the issue refers to a large task, break it in smaller issues that can be solved in less than 45 days;
• Label the issue as wontfix or wontfix for now and close it.

[raphaeltimbo]

We are not having this issue now.