In this paper, the multi-step differential transform method (MDTM), one of the most effective method, is implemented to compute an approximate solution of the system of nonlinear differential equations governing the problem. It has been attempted to show the reliability and performance of the MDTM in comparison with the numerical method (fourth-order Runge–Kutta) and other analytical methods su...

We consider a viscous incompressible fluid filling an infinite horizontal domain bounded at the bottom by a plane wall and at the top by a rough wall. The latter is assumed to consist of a plane wall covered with periodically distributed asperities which size depends on a small parameter ε > 0. The assumption of sharp asperities is made, that is the height of the asperities does not vanish as ε...

Plane Couette flow and pressure-driven pipe flow are two examples of flows where turbulence sets in while the laminar profile is still linearly stable. Experiments and numerical studies have shown that the transition has features compatible with the formation of a strange saddle rather than an attractor. In particular, the transition depends sensitively on initial conditions and the turbulent s...

Various experiments have outlined generic properties of the subcritical transition to turbulence in plane Couette flow. A low order model of a self-sustaining process has been derived by Waleffe [11] from the Navier-Stokes equations for a sinusoidal shear flow. This paper investigates the weakly non-linear properties and the phase space analysis of this model, including the dependence on the mo...

We pioneered NMR studies of concentrated suspensions starting in the late 1980’s (Majors, et al., 1989; Altobelli, et al., 1991; Abbott, et al., 1991). In those studies, we measured concentration and velocity of the liquid component in either in pipe or Couette flow. If we compare these early studies of suspensions with more recent ones (Hampton, et al., 1997), imaging time has gone from 40 min...

Granular flows occur widely in nature and industry, yet a continuum description that captures their important features is yet not at hand. Recent experiments on granular materials sheared in a cylindrical Couette device revealed a puzzling anomaly, wherein all components of the stress rise nearly exponentially with depth. Here we show, using particle dynamics simulations and imaging experiments...

− The two-dimensional linear stability of creeping plane Couette and Poiseuille flow of a viscoelastic fluid with viscous heating is investigated using a Galerkin-type Chebyshev collocation approach and a non-isothermal formulation of the FENE-P constitutive model. Viscous heating is observed to have a destabilizing/stabilizing tendency for Couette/Poiseuille flow at long to moderate disturbanc...

We conduct a global, weakly nonlinear analysis of the magnetorotational instability (MRI) in a Taylor-Couette flow. This is a multiscale perturbative treatment of the nonideal, axisymmetric MRI near threshold, subject to realistic radial boundary conditions and cylindrical geometry. We analyze both the standard MRI, initialized by a constant vertical background magnetic field, and the helical M...

We present a finite-volume formulation for the lattice Boltzmann method (FVLBM) based on standard bilinear quadrilateral elements in two dimensions. The accuracy of this scheme is demonstrated by comparing the velocity field with the analytical solution of the Navier-Stokes equations for time dependent rotating Couette flow and Taylor vortex flow. To demonstrate the flexibility of the scheme, w...

This work is devoted to the study of transient growth of perturbations in the Taylor–Couette problem due to linear nonnormal 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 ...