Přijďte k nám ve dnech 12., 14. a 16. listopadu 2019, ať vidíte, na čem děláme! Více zde.

Lecture

Prof. Can Fuat Delale received his M.Sc. degree in Physics in 1979 at Lehigh University (USA) and his Ph.D. degree in Fluid Mechanics and Thermodynamics in 1983 at Brown University (USA). He is a member of a number of scientific societies, holder of a number of prizes, fellowships and awards and the referee for a number of distinguished scientific journals. More details about his CV including the list of his publications can be found here. Currently he is a professor at Işık University, Faculty of Engineering, Department of Mechanical Engineering, Istanbul, Turkey.

Abstract:

In the first part, the bubble fission model of Delale and Tunc [1] together with a criterion for the occurrence of bubble fission [2] are combined for implementation in cavitating flows. In particular, results of the model are compared with different experiments. Inclusion of thermal damping in the model is also discussed for future work.

In the second part, unsteady quasi-one-dimensional and two-dimensional bubbly cavitating nozzle flows are considered using a homogeneous bubbly flow model. For quasi-one-dimensional nozzle flows, the system of model equations is reduced to two evolution equations for the flow speed and bubble radius and the initial and boundary value problems for the evolution equations are formulated. Results obtained for quasi-one-dimensional nozzle flows capture the measured pressure losses due to cavitation, but they turn out to be insufficient in describing the two-dimensional structures. For this reason, model equations for unsteady two-dimensional bubbly cavitating nozzle flows are considered and, by suitable decoupling, they are reduced to evolution equations for the bubble radius and for the velocity field, the latter being determined by an integro-partial differential system for the unsteady acceleration. This integro-partial differential system constitutes the fundamental equations for the evolution of the dilation and vorticity in two-dimensional cavitating nozzle flows. The initial and boundary value problem of the evolution equations are then discussed and a method to integrate the equations is introduced.

1] C.F. Delale and M. Tunc, A bubble fission model for collapsing cavitation bubbles. Phys. Fluids, 16(11), 4200-4203 (2004).

[2] P. Petrik, Mathematical Analysis and numerical algorithm for the Rayleigh-Plesset equation around the violent bubble collapse, MS Thesis, Charles University, 2010.