GLOBAL INSTABILITIES OF THREE-DIMENSIONAL CAVITY FLOWS

Taking advantage of available experimental essays, the behaviour of an incompressible three-dimensional open cavity flow is studied. For a given configuration the very first bifurcation, which leads to the apparition of Taylor-Görtler like structures, has been detected and characterised. It is therefore shown that the presence of side-walls has a strong influ- ence on the morphology of the intra-cavitary flow and on the dynam- ics of the first instability itself. In order to have a better understanding on the physical phenomena that leads to instability, a global instabil- ity analysis has been conducted on the fully three-dimensional flow. Numerical simulations are conducted by using the open-source SEM code NEK5000; global stability analysis is carried-out by using a time- stepping technique implemented inside the code itself, based on the Arnoldi’s method.