Observation of magnetocoriolis waves in a liquid metal Taylor-Couette experiment

nsCouette -- A high-performance code for direct numerical simulations of turbulent Taylor-Couette flow

We present nsCouette, a highly scalable software tool to solve the Navier-Stokes equations for incompressible fluid flow between differentially heated and independently rotating, concentric cylinders. It is based on a pseudospectral spatial discretization and dynamic time-stepping. It is implemented in modern Fortran with a hybrid MPI-OpenMP parallelization scheme and thus designed to compute turbulent flows at high Reynolds and Rayleigh numbers. An additional GPU implementation (C-CUDA) for intermediate problem sizes and a basic version for turbulent pipe flow (nsPipe) are also provided.

分层和扩散流体中泰勒-库埃特流的离心不稳定性

Centrifugal instability of Taylor-Couette flow in stratified and diffusive fluids

研究了分层和扩散流体中泰勒-库埃特流的离心不性，发现热扩散和分层对不性的影响可通过参数PN=N²Pr描述，并通过DNS和LSA分析了非线性特征和混沌状态。

Taylor-Couette flow for astrophysical purposes

A concise review is given of astrophysically motivated experimental and theoretical research on Taylor-Couette flow. The flows of interest rotate differentially with inner cylinder faster than outer one but are linearly stable against Rayleigh's inviscid centrifugal instability. At shear Reynolds numbers as large as 10^6, hydrodynamic flows of this type (quasi-keplerian) appear to be nonlinearly stable: no turbulence is seen that cannot be attributed to interaction with the axial boundaries, rather than the radial shear itself. Direct numerical simulations agree, although they cannot yet reach…

Axisymmetry vs. nonaxisymmetry of a Taylor-Couette flow with azimuthal magnetic fields

The instability of a supercritical Taylor-Couette flow of a conducting fluid with resting outer cylinder under the influence of a uniform axial electric current is investigated for magnetic Prandtl number Pm=1. In the linear theory the critical Reynolds number for axisymmetric perturbations is not influenced by the current-induced axisymmetric magnetic field but all axisymmetric magnetic perturbations decay. The nonaxisymmetric perturbations with m=1 are excited even without rotation for large enough Hartmann numbers ("Tayler instability"). For slow rotation their growth rates scale with the A…

Dissipative Taylor-Couette flows under the influence of helical magnetic fields

The linear stability of MHD Taylor-Couette flows in axially unbounded cylinders is considered, for magnetic Prandtl number unity. Magnetic fields varying from purely axial to purely azimuthal are imposed, with a general helical field parameterized by β=B_ϕ/B_z. We map out the transition from the standard MRI for β=0 to the nonaxisymmetric Azimuthal MagnetoRotational Instability (AMRI) for β\to \infty. For finite β, positive and negative wave numbers m, corresponding to right and left spirals, are no longer identical. The transition from β=0 to β\to\infty includes all the possible forms of MRI …

The angular momentum transport by standard MRI in quasi-Kepler cylindric Taylor-Couette flows

The instability of a quasi-Kepler flow in dissipative Taylor-Couette systems under the presence of an homogeneous axial magnetic field is considered with focus to the excitation of nonaxisymmetric modes and the resulting angular momentum transport. The excitation of nonaxisymmetric modes requires higher rotation rates than the excitation of the axisymmetric mode and this the more the higher the azimuthal mode number m. We find that the weak-field branch in the instability map of the nonaxisymmetric modes has always a positive slope (in opposition to the axisymmetric modes) so that for given ma…