Competition of spirals in Couette – Taylor system between counter rotating cylinders leads, for small supercriticality to the formation of localized source. Measuring the group velocity as function of the amplitude, we have determined that waves forming such source have anomalous dispersion, in the sense that phase and linear group velocity of each have opposite signs. Our Couette Taylor system...

We present a numerical scheme for viscoelastic flow based on a second-order central differencing method recently introduced in the context of incompressible newtonian flow; the incompressibility constraint is treated with the projection method. The result is a simple and efficient scheme that is readily adaptable to a wide class of differential constitutive equations and flow geometries. We imp...

Aims. The stability of dissipative Taylor-Couette flows with an axial stable density stratification and a prescribed azimuthal magnetic field is considered. Methods. Global nonaxisymmetric solutions of the linearized MHD equations with toroidal magnetic field, axial density stratification and differential rotation are found for both insulating and conducting cylinder walls. Results. Flat rotati...

This work is devoted to the study of transient growth of perturbations in the Taylor–Couette problem due to linear mechanisms. The study is carried out for a particular small gap case and is mostly focused on the linearly stable regime of counter-rotation. The exploration covers a wide range of inner and outer angular speeds as well as axial and azimuthal modes. Significant transient growth is ...

In Taylor-Couette flow the total energy dissipation rate and therefore the drag can be determined by measuring the torque on the system. We do so for Reynolds numbers between Re=7 x 10(4) and Re=10(6) after having injected (i) small bubbles (R=1 mm) up to a volume concentration of alpha=5% and (ii) buoyant particles (rhop/rhol=0.14) of comparable volume concentration. In case (i) we observe a c...

The linear stability of the dissipative Taylor-Couette flow with an azimuthal magnetic field is considered. Unlike ideal flows, the magnetic field is a fixed function of a radius with two parameters only: a ratio of inner to outer cylinder radii, eta, and a ratio of the magnetic field values on outer and inner cylinders, muB. The magnetic field with 0<muB<1/eta stabilizes the flow and is called...

M. AVILA, M. J. BELISLE†, J. M. LOPEZ, F. MARQUES AND W. S. SARIC Departament de Fı́sica Aplicada, Univ. Politècnica de Catalunya, Barcelona 08034, Spain Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 5287, USA Department of Mathematics and Statistics, Arizona State University, Tempe, AZ 85287, USA Department of Aerospace Engineering, Texas A&M University...

Recent studies have brought into question the view that at sufficiently high Reynolds number turbulence is an asymptotic state. We present direct observation of the decay of turbulent states in Taylor-Couette flow with lifetimes spanning five orders of magnitude. We also show that there is a regime where Taylor-Couette flow shares many of the decay characteristics observed in other shear flows,...

The linear stability theory of Taylor-Couette flows (unbounded in z) is described including magnetic fields, Hall effect or a density stratification in order to prepare laboratory experiments to probe the stability of differential rotation in astrophysics. If an axial field is present then the magnetorotational instability (MRI) is investigated also for small magnetic Prandtl numbers. For rotat...