Tutorial 2

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""" 
This example shows how to simulate advection of temperature
in a cylindrical tank without any bed material. At the bottom (y=0)
the temperature is fixed at 80℃ (direchlet-type BC), and at the top (y=1)
a neumann-type BC is applied. 20 nodes are used to discretize the domain.
The fluid is water. The simulation time is 600 seconds, and the output
is saved every 60 seconds.
As opposed to the previous example, the mass flow rate is not constant.
It is set to 0.1 kg/s for the first 400 seconds. Between 400 and 500
 seconds, the mass flow decreased so that -0.1 kg/s is reached 
 after 500 seconds.
"""

import openterrace
import matplotlib.pyplot as plt

def main():
    ot = openterrace.Simulate(t_end=600, dt=0.01)

    fluid = ot.create_phase(n=500, type='fluid')
    fluid.select_substance_on_the_fly(rho=1000, cp=4200, k=0.6)
    fluid.select_domain_shape(domain='cylinder_1d', D=0.3, H=1)
    fluid.select_schemes(diff='central_difference_1d', conv='upwind_1d')
    fluid.select_initial_conditions(T=273.15+20)
    fluid.select_massflow(mdot=[
                                [0, 0.1],
                                [400, 0.1],
                                [500, -0.1]
                                ])

    fluid.select_bc(bc_type='fixed_value', 
                    parameter='T',
                    position=(slice(None, None, None), 0),
                    value=273.15+80)
    fluid.select_bc(bc_type='zero_gradient', 
                    parameter='T',
                    position=(slice(None, None, None), -1),
                    value=0)
    fluid.select_output(times=range(0, 10*60+45, 45))

    ot.run_simulation()

    plt.plot(fluid.node_pos,fluid.data.T[:,0,:].T-273.15, label=fluid.data.time)
    plt.legend(title='Simulation time (s)')
    plt.show()
    plt.xlabel(u'Cylinder position (m)')
    plt.ylabel(u'Temperature (℃)')
    plt.grid()
    plt.grid(which='major', color='#DDDDDD', linewidth=1)
    plt.grid(which='minor', color='#EEEEEE', linestyle=':', linewidth=0.8)
    plt.minorticks_on()
    plt.savefig('ot_plot_tutorial2.svg')

if __name__ == "__main__":
    main()