Verification test cases

## Topics | |

Advection schemes | |

These test cases solve the 2D advection equation. | |

Laplacian verification test cases | |

Verification of the solution of the Laplacian. | |

Navier verification test cases | |

Verification of the solution of the Navier-Stokes equations. | |

Phase advection verification test cases | |

Verification of the solution of the phase advection equation. | |

Surface tension verification test cases | |

Verification of the solution of surface tension problems. | |