For free flow models, we take the number of "physical" equations (e.g. 4 for a 3D NavierStokes problem, 3 velocity components and pressure) and substract the number of dimensions. This yields the number of equations to be solved on the cell centers. Works also for non-isothermal models.
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template<class TypeTag>
struct Dumux::Properties::NumEqCellCenter< TypeTag, TTag::StaggeredFreeFlowModel >
For free flow models, we take the number of "physical" equations (e.g. 4 for a 3D NavierStokes problem, 3 velocity components and pressure) and substract the number of dimensions. This yields the number of equations to be solved on the cell centers. Works also for non-isothermal models.