in this research, the effect of surface roughness and bubble injection on skin friction and hydrodynamic drag force has been numerically considered. this research is based on taylor-couette flow. considered flow includes two concentric cylinders which internal cylinder is movable and external is immovable. the effective equations on the flow includes: equations of momentum, continuous, turbulen...

In free-surface flows, some flow instabilities may be observed, for example in pooled stepped spillways and hydraulic jumps. These instabilities may include some pulsations and oscillations. Most traditional two-phase flow analyses would yield some air-water turbulent flow results combining the contributions of the slow fluctuations and of the turbulent motion. Herein a new turbulence decomposi...

A tidal bore is a positive surge propagating upstream as the tidal flow turns to rising in river mouths exhibiting a converging funnelled channel forms during low freshwater conditions. While some recent laboratory experiments brought new insights to the turbulent motion generated by tidal bores, a numerical model based upon the Navier-Stokes equations is proposed to investigate the complicated...

this study is concerned with the prediction of particles’ velocity in a dilute turbulent gas-solidboundary layer flow using a fully eulerian two-fluid model. the closures required for equationsdescribing the particulate phase are derived from the kinetic theory of granular flows. gas phaseturbulence is modeled by one-equation model and solid phase turbulence by mlh theory. resultsof one-way and...

Stirred tanks are widely used in process industries for blending of singleand/or multiple-phase fluids, which often involves mass and/or heat transfer, chemical reactions, etc. Deep knowledge of flow field in the stirred tank is necessary to carry out these unit operations efficiently. As a result, extensive investigations of the flow in stirred tanks have been conducted over the past several d...

The regulation of turbulent transport by zonal flows is studied experimentally on a flux surface of the stellarator experiment TJ-K. Data of 128 Langmuir probes at different toroidal and poloidal positions on a single flux surface enable us to measure simultaneously the zonal flow activity and the turbulent transport in great detail. A reduction of turbulent transport by 30% during the zonal fl...