Nesting models

Here is a guide on configuring MOHID Water with nested models.

In MOHID GUI

• Create a new project in MOHID GUI,
• Create a Model by inserting a new Simulation,
  • Setup your model
• Create a Submodel by inserting a new Simulation from the current Simulation. The new simulation should fold into the previous one.
  • Setup the model

Setting up the files

The whole issue is how to define the open-boundary conditions for the submodel. Basically we suggest to use a Flather radiation condition at the open boundaries that will radiate the water level and the barotropic flux in conjunction with a flow relaxation scheme spanning a few cells from the open-boundaries to the interior for the velocities (u and v).

Keywords in Hydrodynamic.dat

In the submodel hydrodynamic file

SUBMODEL          : 1

!Flather radiation scheme using the father model as a reference solution.
RADIATION         : 2
LOCAL_SOLUTION    : 2

!Activate the Flow relaxation scheme
DATA_ASSIMILATION : 1

Keywords in Assimilation.dat

In the submodel assimilation file

<beginproperty>
NAME                    : velocity U
UNITS                   : m/s
DIMENSION               : 3D
OUTPUT_HDF              : 1

COLD_RELAX_PERIOD       : 432000
COLD_ORDER              : 5

<<begin_field>>
DEFAULTVALUE            : 0
INITIALIZATION_METHOD   : HDF
FILE_IN_TIME            : HDF
FILENAME                : ../../GeneralData/Reference_vel_U.hdf5
TYPE_ZUV                : z
<<end_field>>

<<begin_coef>>
DEFAULTVALUE            : 1e9
TYPE_ZUV                : u
FILE_IN_TIME            : NONE
REMAIN_CONSTANT         : 1
INITIALIZATION_METHOD   : ASCII_FILE
FILENAME                : ../../GeneralData/RelaxationCoefs_U.dat

<<end_coef>>

<endproperty>


<beginproperty>
NAME                    : velocity V
UNITS                   : m/s
DIMENSION               : 3D
OUTPUT_HDF              : 1

COLD_RELAX_PERIOD       : 432000
COLD_ORDER              : 5

<<begin_field>>
DEFAULTVALUE            : 0
INITIALIZATION_METHOD   : HDF
FILE_IN_TIME            : HDF
FILENAME                : ../../GeneralData/Reference_vel_V.hdf5
TYPE_ZUV                : z
<<end_field>>

<<begin_coef>>
DEFAULTVALUE            : 1e9
TYPE_ZUV                : v
FILE_IN_TIME            : NONE
REMAIN_CONSTANT         : 1
INITIALIZATION_METHOD   : ASCII_FILE
FILENAME                : ../../GeneralData/RelaxationCoefs_V.dat

<<end_coef>>

<endproperty>