Jan Götz

Jan Götz did his master's thesis at the chair for System Simulation under supervision of Prof. Rüde at University Erlangen-Nürnberg. He graduated from Computational Engineering/BGCE in 2006, and is now PhD student at the Department of Computer Science in Erlangen (see his homepage).

Master's Thesis:
Numerical Simulation of Bloodflow in Aneurysms using the Lattice Boltzmann Method

AneurysmAneurysm near a blood vessel trifurcation

The largest excess mortality in Germany is due to cardiovascular diseases among both males and females. To diagnose these diseases, modern techniques such as computer tomography, digital subtraction angiography, or magnetic resonance imaging, play a key role in today's medical care. They allow doctors a detailed insight in the human body up to a resolution of 1mm and below. On the other hand, hemodynamic values like shear stress or pressure could hardly be measured or visualized, but might be essential for further treatment of the patient. In case of aneurysms no one can predict the exact risk of rupturing. Particularly the hemodynamics in vessel malfunctions may give the doctor additional information and may influence further treatment. A bloodflow simulation can provide this information.

The Lattice Boltzmann method is known to be a highly efficient method for the simulation of flow problems, especially for complex geometries. Due to this fact it looks like the perfect method for the simulation of bloodflow in the human brain. But the memory requirements for the large domain sizes make these simulations only possible on supercomputers. In his thesis, Jan Goetz investigated a method that drastically reduces the memory requirements for a bloodflow simulation in the brain and allows a simulation on smaller PCs. The procedure from data acquisition over data preparation and simulation to the visualization is discussed in detail. The simulation is based on a standard Lattice Boltzmann approach with an adapted data structure, which also has the flexibility to handle moving boundaries. Additional to velocity and density values, which are the standard output of the Lattice Boltzmann method, the stress tensor is calculated and visualized. Two relevant geometries are simulated and the results are shown and discussed. Furthermore, the costs regarding memory and computational power are investigated.

Estimation of optical flow Computation of effective shear stresses in an aneurysm during pulse.

Material