The methods of the bifurcation theory of codimension two, together with computer calculations, are used to investigate stationary, periodic, and quasiperiodic flows with two and three independent frequencies, as well as chaotic regimes of fluid flow between two infinite rotating permeable concentric cylinders near the intersection of the bifurcations initiating secondary stationary flow and self-oscillations with azimuthal waves.The experimental investigations [1][2][3] have shown that with increase in the Reynolds number the main stationary rotational-symmetric fluid flow between two rotating permeable cylinders changes for a secondary stationary flow or a self-oscillatory regime with waves traveling in the azimuthal direction. The further increase in the Reynolds number leads to complication of the fluid flow structure and gives rise to different complicated regimes and then to turbulence.The calculations of neutral curves made it possible to found that at certain parameter values the curves corresponding to rotational-symmetric and oscillatory three-dimensional instabilities intersect [4][5][6][7][8].In the mid-eighties of the last century V.I. Yudovich in Russia and J. Iooss and P. Chossat in France devised the bifurcation theory of codimension two for hydrodynamic flows with cylindrical symmetries. This made it possible to investigate different fluid flow regimes in the vicinity of the point of intersection of bifurcations of the origin of secondary stationary flow and azimuthal waves for impermeable cylinders [9,10]. In this study, this theory is applied for calculating complicated fluid flows in the Couette-Taylor problem for permeable cylinders.
GOVERNING EQUATIONS AND MAIN REGIMELet a gap between two solid infinite permeable concentric cylinders, R 1 and R 2 in radii (R 1 < R 2 ) rotating at angular velocities Ω 1 and Ω 2 be filled with a viscous homogeneous incompressible fluid. We will assume that there are no external body forces. The quantities R 1 , Ω 1 R 1 ,a nd 1/Ω 1 are taken for the length, velocity, and time scales, respectively.In the cylindrical coordinates r, ϕ, z, with the z axis aligned with the cylinder axis, the dimensionless Navier-Stokes and continuity equations take the form: