Runs with easy topography

The first example on this page shows a simulation of a single surface-mounted cube in neutral channel flow with constant bulk velocity. A constant bulk velocity means that the volume flow at the inflow boundary equals at each time step the volume flow at the outflow. For volume flow conservation, the initial profiles are used. Besides, cyclic lateral boundary conditions are used. The 3d-model is initialized with constant vertical profiles. Coriolis force is switched off (omega = 0.0). A constant volume flow (i.e. constant bulk velocity) is maintained (conserve_volume_flow = .T.). The flow is explicitly set neutral (neutral = .T.), i.e. the prognostic equation for temperature and other buoyancy terms must not be calculated, which saves computation time. To set the channel flow boundary condition, the horizontal velocity components at the domain top are kept zero (bc_uv_t = 'dirichlet_0'). The cube is constructed using the rasterized topography mode (topography = 'read_from_file') with the default topography_grid_convention = 'cell_center'. You can find the input files for the simulation in the trunk.

In a second example, the cube is constructed using the single building topography mode (topography = 'single_building') with the default topography_grid_convention = 'cell_edge'. The results of the two examples should be the same. The parameter file using the single building topography mode is attached to this page.

A third simulation example using a idealized single street canyon under neutral conditions can be found here. A constant bulk velocity is used as in the first example, which means that the volume flow at the inflow boundary equals at each time step the volume flow at the outflow. For volume flow conservation, the initial profiles are used. The canyon is 40 m high and wide (x-direction), infinitely long in y-direction, and centered in the model domain.

Finally, a fourth example using a more complex topography than just a single building or street canyon can be found under the EXAMPLES folder in the trunk. This example shows the flow around a single 3d idealized mountain. The mountain shape is Gaussian. The inversion height lies below the mountain top so that a part of the topography resides in stable stratification. Cyclic lateral boundary conditions are used. The 3d-model is initialized with the solution of the 1d-model. In addition, Rayleigh damping is switched on. The topography file in ASCII format is created with aid of a 2d Gauss function.