We propose a theory for axial segregation of suspensions of non-neutrally buoyant particles in a rotating cylinder. The cylinder is oriented in the horizontal plane, so that any axial forces must arise from interparticle interactions. We show that the hydrodynamic interaction between pairs of particles produces a relative motion in the axial direction, independent of the gravitational force. If...

Direct numerical simulations of a turbulent spiral Poiseuille flow (SPF) in narrow-gap geometry at low Taylor number have been performed to analyse the reverse transition dynamics. The presently investigated SPF results from Taylor–Couette arrangement with rotating inner cylinder and stationary outer one, subject time-constant axial pressure gradient. Keeping fixed reducing Reynolds number, sev...

in this article, thermo-elastic-behavior of a thick-walled cylinder made from a polystyrene nanocomposite reinforced with functionally graded (fg) single-walled carbon nanotubes (swcnts) was carried out in radial direction while subjected to a steady state thermal field. the swcnts were assumed aligned, straight with infinite length and a uniform layout. two types of variations in the volume fr...

Presented in this paper is an analytic approximation to the thermal-fluid problem involving mixed convective heat transfer from a rotating isothermal cylinder placed in a non-uniform stream shear flow. The approximation is obtained using a series expansion of the scaled boundary layer equations in terms of an appropriate boundary layer variable. The resulting approximation is valid both for sma...

Water solution of volatile organic compounds (VOCs) in air, especially explosive materials, is required to detect VOCs by biosensors efficiently. We developed a collecting device like olfactory mechanism of animals: thin film of water including odorant binding proteins (OBPs), which play a major role in transport of hydrophobic odor molecules to olfactory receptors. Thin liquid film was generat...

In this paper, we present results of three-dimensional direct numerical simulations of the spiral turbulence phenomenon in a range of moderate Reynolds numbers, in which alternating intertwined helical bands of turbulent and laminar fluids coexist and propagate between two counter-rotating concentric cylinders. We show that the turbulent spiral is comprised of numerous small-scale azimuthally e...

We present numerical simulations to demonstrate the existence of laminar spiral flows between both finite and infinite length concentric cylinders and finite truncated cones where only the inner wall rotates. The velocities and pressure are calculated by a spectral element/Fourier method. Different gap ratios are investigated. Convergence of the numerical results is shown with reference to flow...

The transition to turbulence induced by counter-rotating wall-normal rotating cylindrical roughness pairs immersed within a laminar boundary layer on flat plate is investigated with direct numerical simulations, dynamic mode decomposition (DMD) and perturbation kinetic energy (PKE) analysis. As long as the cylinder stub rotating, wake contains steady dominating inner vortex (DIV) surrounded sec...

Adjoint formulation is employed for the optimal control of ow around a rotating cylinder, governed by the unsteady Navier–Stokes equations. The main objective consists of suppressing Karman vortex shedding in the wake of the cylinder by controlling the angular velocity of the rotating body, which can be constant in time or time-dependent. Since the numerical control problem is ill-posed, regula...