In gas dynamics, relationships between pressure and temperature are modeled using so-called equations of state. While pressure and temperature are perceived as measurable variables on a "large scale", they do not exist as such in a highly rarefied atmosphere or in microchannels, where a flow can only be described by the movement of molecules. In addition to translational and rotational kinetic energies, molecules also store binding energies, but neither a pressure nor a temperature can be assigned to them.

The research field of microfluid dynamics thus pursues the goal of finding explanations for macroscopic effects in flows in the outer atmosphere or in propulsion systems of small satellites, which are inconceivable on the basis of the assumption of a continuous fluid. The topics to be investigated are therefore

• Gas flows in microchannels
• Molecular wall interaction
• Macroscopic modeling of material properties (wall stress, toughness, thermal conductivity)
• Dilute gas flows in the outer atmosphere

The field of application remains flows in which the molecular diffusion and wall interaction behavior must be reliably predicted in the smallest spaces and with extremely low molecular density in order to be able to make more precise statements about the efficiency of a gas analysis device, the tightness of a gas seal or the efficiency of a micro-engine.