The transitions of the flow in an enclosed cylinder driven by the constant rotation of an endwall, from steady axisymmetric flow to aperiodic flow characterized by intermittent bursting dynamics where all the spatial and spatio-temporal symmetries have been broken, is studied numerically. The problem is controlled by two parameters, the Reynolds number and the cylinder aspect ratio. We vary the...

We report three-dimensional direct numerical simulations of the turbulent flow between counter-rotating concentric cylinders with a radius ratio 0.5. The innerand outer-cylinder Reynolds numbers have the same magnitude, which ranges from 500 to 4000 in the simulations. We show that with the increase of Reynolds number, the prevailing structures in the flow are azimuthal vortices with scales muc...

We propose a method for extracting a rotating limb region and estimating its motion parameters, which is based on the curl of optical flow. Regarding the optical flow as a vector field, the proposed method computes the curl of the optical flow to extract a rotating region. The method assumes that one angular velocity varies in a short time period. By using the EM algorithm, the center of rotati...

We characterize the two-dimensionalization process in the turbulent flow produced by an impeller rotating at a rate ω in a fluid rotating at a rate Ω around the same axis for Rossby number Ro = ω/Ω down to 10 −2. The flow can be described as the superposition of a large-scale vertically invariant global rotation and small-scale shear layers detached from the impeller blades. As Ro decreases, th...

Geometric inversion is applied to two-dimensional Stokes flow in the objective to find new Stokes flow solutions. The principle of this method and the relations between the reference and inverse fluid velocity fields are presented. They are followed by applications to the flow between two parallel plates induced by a rotating or a translating cylinder. Thus hydrodynamic characteristics of flow ...

The flow in a rotating cylinder driven by the differential rotation of its top endwall is studied by numerically solving the time-dependent axisymmetric Navier–Stokes equations. When the differential rotation is small, the flow is well described in terms of similarity solutions of individual rotating disks of infinite radius. For larger differential rotations, whether the top is co-rotating or ...

The present investigation studies the behavior of steady flow of visco-elastic liquid between two porous coaxial circular cylinders, where both the cylinders are rotating with different uniform angular velocities about the common axis. In addition, the inner cylinder has uniform velocity along the axis and the visco-elastic fluid, which is a Walters liquid B′, is allowed to flow in the annulus....

We study the dynamical structure of a cooling dominated rotating accretion flow around a spinning black hole. We show that non-linear phenomena such as shock waves can be studied in terms of only three flow parameters, namely, the specific energy (E), the specific angular momentum (λ) and the accretion rate (ṁ) of the flow. We present all possible accretion solutions. We find that a significant...

Introduction A hydrocarbon flame can naturally and readily provide an appropriate high-temperature environment with abundant radical concentrations required for the growth of carbon nanotubes (CNTs) [1] or carbon nano-onions (CNOs) [2]. Therefore, flame synthesis shows a more promising potential for inexpensive and mass production of high-purity carbon nanostructures than other synthesis method...

In this paper, an unstructured Chimera mesh method is used to compute incompressible flow around a rotating body. To implement the pressure correction algorithm on unstructured overlapping sub-grids, a novel interpolation scheme for pressure correction is proposed. This indirect interpolation scheme can ensure a tight coupling of pressure between sub-domains. A moving-mesh finite volume approac...