The gas fluid dynamics in structured packings of distillation and absorption columns is investigated especially with respect to the mixing behavior of component concentrations. The first part comprises a fundamental experiment of a single crisscrossing junction which represents a repetitive periodic element of the packing geometry. Particularly, the mixing efficiency of a tracer component is measured. Additionally, CFD simulations are conducted and analyzed with regard to their capacity to represent the distribution of the tracer component. In the second part the implementation of a new mesoscale model for structured packings (StructuPack) is described which is motivated by the need to resolve local velocities, pressures and concentrations with low computational cost as compared to microscale CFD simulations. Finally, an exemplary scenario in a packing section is calculated both by CFD and the mesoscale model to demonstrate the model's potential to resolve local pressures, velocities and tracer concentrations using comparatively few computational resources.