# locateModel_engineSearchIB command¶

## Syntax¶

Defined in couplingProperties dictionary.

```
locateModel engineIB;
engineIBProps
{
treeSearch switch1;
zSplit value1;
xySplit value2;
checkPeriodicCells;
}
```

*switch1*= names of the finite volume scalar fields to be temporally averaged*value1*= number of z-normal layers for satellite points*value2*= number of satellite points in each layer*checkPeriodicCells*= (optional, default false) flag for considering the minimal distance to all periodic images of this particle

## Examples¶

```
locateModel engineIB;
engineIBProps
{
treeSearch false;
zSplit 8;
xySplit 16;
}
```

## Description¶

The locateModel “engine” locates the CFD cell and cellID corresponding to a given position. This locate model is especially designed for parallel immersed boundary method. Each particle is represented by “satellite points” if it is distributed over several processors.

The engineSearchIB locate Model can be used with different settings to use different algorithms:

- treeSearch false; will execute some geometric (linear) search using the last known cellID (recommended)
- treeSearch true; will use a recursive tree structure to find the cell.

This model is a modification of the engine search model. Instead of using the centre-cell as starting point for the engine search, further satellite points located on the surface of the sphere are checked. This ensures that (parts of) spheres can be located even when their centre is on another processor. This is especially important for parallel computations, when a sphere is about to move from one processor to another.

## Restrictions¶

Only for immersed boundary solvers!