# forceModel_ShirgaonkarIB command¶

## Syntax¶

Defined in couplingProperties dictionary.

```
forceModels
(
ShirgaonkarIB
);
ShirgaonkarIBProps
{
velFieldName "U";
pressureFieldName "p";
twoDimensional;
depth scalar1;
verbose switch1;
treatForceExplicit switch2;
};
```

*U*= name of the finite volume fluid velocity field*p*= name of the finite volume pressure field*twoDimensional*= optional keyword for conducting a two dimensional calculation*scalar1*= optional, only necessary if twoDimensional is active*switch1*= (optional, default false) sub model switch, see*forceSubModel*for details*switch2*= (optional, default false) sub model switch, see*forceSubModel*for details

## Examples¶

```
forceModels
(
ShirgaonkarIB
);
ShirgaonkarIBProps
{
velFieldName "U";
pressureFieldName "p";
}
```

## Description¶

The force model performs the calculation of forces (e.g. fluid-particle interaction forces) acting on each DEM particle. The ShirgaonkarIB model calculates the drag force (viscous and pressure force) acting on each particle in a resolved manner (see Shirgaonkar et al. (2009): “A new mathematical formulation and fast algorithm for fully resolved simulation of self-propulsion”, Journal of Comp. Physics). This model is only suited for resolved CFD-DEM simulations where the particle is represented by immersed boundary method.

**References:**

SHIRGAONKAR, A.A., MACIVER, M.A. and PATANKAR, N.A., (2009), “A new mathematical formulation and fast algorithm for fully resolved simulation of self-propulsion”, J. Comput. Phys., 228, 2366-2390.

## Restrictions¶

Only for immersed boundary solvers.