Subgrid |  |
In certain cases, greater spatial resolution may be needed to better resolve small-scale geometry in only part of the parent simulation domain. In that case, a second, smaller, nested domain can be created within the parent domain that allows for higher spatial mesh resolution. More than one subgrid may be used in a given simulation to resolve small-scale features with large separation between them.
Creating the SubgridClick Sub Grid under the EMA3D ribbon within the Simulation section.
It is then possible to adjust the subgrid properties in the Properties Panel. The properties are generally the same as those for the parent domain, but the new properties are outlined in the table below. The time and spatial step size properties are not adjustable, as they are based on the parent domain parameters. The subgrid can be run with parallel divisions, but they need to be set within the subgrid properties as they do not carry over from the parent domain.
Entry | Meaning |
|---|---|
Coupling Direction | The direction in which waves travel through the subgrid boundary. In indicates that the parent domain simulates first and the signal on the subgrid boundary is used to drive the subgrid simulation (e.g., a plane wave traveling through the entire parent domain). Out indicates that the subgrid simulates first and the signal on the subgrid boundary is used to drive the parent simulation (e.g., a radiating antenna located within the subgrid). |
Mesh Ratio | The number of subgrid mesh cells per parent domain mesh cell. The ratio of each axis can be set individually. |
Padding | Number of coarse mesh cells between the subgrid and its boundary |
Sample Frequency | The number of time steps between updates between the subgrid and its parent domain. EMA3D will select an appropriate number based on the mesh ratio |
Sample Count | Total number of time samples shared between the subgrid and its parent domain. EMA3D will select an appropriate number based on the mesh ratio |
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