Floods and droughts are important features of most running water ecosystems, but the alteration of natural flow regimes by recent human activities, such as dam building, raises questions related to both evolution and conservation. Among organisms inhabiting running waters, what adaptations exist for surviving floods and droughts? How will the alteration of the frequency, timing and duration of ...

We investigate the constant-wall-temperature convective heat-transfer characteristics of a model gaseous flow in two-dimensional micro and nano-channels under hydrodynamically and thermally fully developed conditions. Our investigation covers both the slip-flow regime 0<Kn<0.1, and most of the transition regime 0.1,Kn<10, where Kn, the Knudsen number, is defined as the ratio between the molecul...

We have observed the impingement of two cylindrical liquid jets of either the same liquid, water, or two mutually immiscible liquids, water and methylcyclohexane (MCH), in either air under normal pressure (0.101MPa) or nitrogen gas under elevated pressures up to 4.0MPa. The flow rates of the two jets were adjusted such that they had equal axial momentum. Irrespective of the system pressure, we ...

The flow in a rapidly rotating cylinder forced to precess through a nutation angle α is investigated numerically, keeping all parameters constants except α, and tuned to a triadic resonance at α = 1◦. When increasing α, the flow undergoes a sequence of well-characterized bifurcations associated with triadic resonance, involving heteroclinic and homoclinic cycles, for α up to about 4◦. For large...

We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convection–diffusion equation is derived to describe the time evolution of the fluid–fluid interface. In the early time period, the fl...

The aim of this Letter is to characterize the flow regimes of suspensions of finite-size rigid particles in a viscous fluid at finite inertia. We explore the system behavior as a function of the particle volume fraction and the Reynolds number (the ratio of flow and particle inertia to viscous forces). Unlike single-phase flows, where a clear distinction exists between the laminar and the turbu...