# visualiser
import FVis3

class 2Dconvection:

    def __init__(self):

        """
        define variables
        """

    def initialise(self):

        """
        initialise temperature, pressure, density and internal energy
        """

    def timestep(self):

        """
        calculate timestep
        """

    def boundary_conditions(self):

        """
        boundary conditions for energy, density and velocity
        """

    def central_x(self, var):

        """
        central difference scheme in x-direction
        """

    def central_y(self, var):

        """
        central difference scheme in y-direction
        """

    def upwind_x(self, var, v):

        """
        upwind difference scheme in x-direction
        """

    def upwind_y(self, var, v):

        """
        upwind difference scheme in y-direction
        """

    def hydro_solver(self):

        """
        hydrodynamic equations solver
        """

        return dt