Experimental and theoretical studies of stability of fluid motion within an elliptical cylinder

Experimental and theoretical studies are performed of stability of fluid motion within an elliptical cylinder. It is found that depending on cylinder geometry the instability of liquid rotation around the central axis leads to various types of secondary flows characterized by formation of regular vortex flow in planes perpendicular to original motion. The mechanism of instability is studied by perturbation theory applied to linearized hydrodynamics equations which gives the possibility to find the most unstable modes forming the secondary flow.