Numerical simulations using the Lattice Boltzmann Method are conducted on massively parallel supercomputers to explore the detailed dynamics of transitional flows in patient specific anatomical geometries. The methodology is validated against the literature by simulations of stenotic flows and conditions for transition in a purely oscillatory flow are explored. The characteristics of transitional flow in physiological cases are quantified in detail and the implications of such a flow regime on the pathology and pathophysiology of intracranial aneurysms and Chiari I malformation are discussed.weiterlesen