Thermofluid Dynamics
About our research
The primary topic is modeling of unsteady processes in fluid and thermo-dynamics resulting from transient microscale phenomena in plasma and gas dynamics. The correlation between momentum transfer and thermo-fluxes is analyzed by disturbance calculation methods and stability evaluations. To achieve this, the dynamics of microscale particles and molecules has to be modeled. Based on statistical physics the molecular motion is described, e.g. by Brownian motion. Quantities of molecular flows are described through spectral methods as transport equations for the probability density function over the phase space. The research topic focuses on the combination of flow modeling and the thermodynamic aspects of molecular and turbulent flows.
Our fields of research
- Computing particle density distribution in dispersed spray processes for additive manufacturing
- Turbulent wake simulation of bluff body flows and modelling generation, diffusion and dissipation of turbulent structures
- Modeling heat transfer and turbulence production in natural convection flows driven by temperature differences
- Permeation of infused resin, evolution of defects and hardening of solid/liquid fibre composite structures
- Modeling and prediction of leackage flows in fibre-structured vacuum sealings
- Slip modeling of molecular gas dynamics including transition to free-molecular flows
- Ionization modeling in thermo-electric and magneto-plasma-dynamic propulsion systems for space applications
- Magneto-fluid dynamic effects on convective flows in atmosphere and space (e.g. space wheather)
CONTACT
Rarefied Gas Dynamics and Trans-sonic Microflows
In the main field of research the frontiers of classical flow descriptions are investigated. High Knudsen numbers lead to a molecular, non-continuous fluid behavior. As a consequence, high Knudsen numbers deny the description of a flow by a continuous approach and additional statistical models have to be defined. In this case, a quasi-continuous transport model for dispersed systems based on transport equations for statistical moments is used.
Computational Particle-in-Cell modelling for Plasma Flow
Plasma is the most abundant state of matter in the universe, it consists of ionized atoms or molecules and free electrons. Compared to ordinary matter it has some special properties, among other there exist long-ranging attraction and repulsion of charges through electrostatic forces, from which a verity of other fascinating effects emerge. Next to the experimental observation and measuring of plasma in laboratory settings exist the computational simulation of plasma using a variety of methods, one of which is the modeling as fluid using magneto-hydrodynamics.
Electric Propulsion Systems for Space Transport
The present situation of space exploration calls for missions beyond the moon and for such missions, chemical propulsion is not a viable option, except for the case of launch vehicles where high thrust is required. The inability of chemical propulsion systems to achieve higher exhaust velocities is due to limitation in the maximum tolerable temperature in the combustion chamber and to avoid excessive heating. Both these limitations can be overcome by electric propulsion, which is an acceleration of gases by electric and magnetic volume forces.
Turbulence Modeling: Boundary Layers and Scale Transitioning
Thanks to numerous technical studies the physical law of periodic flow instability in fluid flows with high Reynolds numbers is well-known. The laminar positioned stream lines are destroyed by perturbations, which diffuse from the wall through the complete flow domain. The change from a steady laminar stream to an unsteady turbulent flow is defined is investigated by modeling the velocity correlations in the fluid. So called statistical eddy-diffusivity models are used to describe the turbulent momentum and energy diffusion inside the fluid flow.