A simple model for the motion of shape-changing swimmers in Poiseuille flow was recently proposed and numerically explored by Omori et al. ( J. Fluid Mech. , vol. 930, 2022, A30). These explorations hinted that a small number interacting mechanics can drive long-time behaviours this model, cast context well-studied alga Chlamydomonas its rheotactic such flows. Here, we explore analytically via ...

A modal stability analysis shows that plane Poiseuille flow of an Oldroyd-B fluid becomes unstable to a `center mode' with phase speed close the maximum base-flow velocity, $U_{max}$. The governing dimensionless groups are Reynolds number $Re = \rho U_{max} H/\eta$, elasticity $E \lambda \eta/(H^2\rho)$, and ratio solvent solution viscosity $\eta_s/\eta$; here, $\lambda$ is polymer relaxation t...

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...

The cross-stream migration of a deformable drop in two-dimensional Poiseuille flow at finite Reynolds numbers is studied numerically. In the limit of a small Reynolds number (<1), the motion of the drop depends strongly on the ratio of the viscosity of the drop fluid to the viscosity of the suspending fluid. For a viscosity ratio 0.125, the drop moves toward the centre of the channe while for t...

Hydrodynamic electron flow is experimentally observed in the differential resistance of electrostatically defined wires in the two-dimensional electron gas in (Al,Ga)As heterostructures. In these experiments current heating is used to induce a controlled increase in the number of electron-electron collisions in the wire. The interplay between the partly diffusive wire-boundary scattering and th...

The linear stability of plane Poiseuille flow at low Reynolds number of a conducting Oldroyd fluid in the presence of a transverse magnetic field has been investigated numerically. Spectral tau method with expansions in Chebyshev polynomials is used to solve the Orr-Sommerfeld equation. It is found that viscoelastic parameters have destabilizing effect and magnetic field has a stabilizing effec...