Turbulent shear control with oscillatory bubble injection

Bubble breakup in a turbulent shear layer

The breakup of a millimetre size buoyantly rising bubble encountering a horizontal plane turbulent jet is experimentally investigated using high-speed shadowgraphy and acoustic techniques. The bubble diameter to jet height ratio is 0.75 and the jet height based Reynolds number is 4000. The high-speed imaging was recorded at 7 kHz simultaneous with hydrophone output at 100 kHz. Bubble breakup ev...

Turbulent Dynamos with Shear and Fractional Helicity

Dynamo action owing to helically forced turbulence and large-scale shear is studied using direct numerical simulations. The resulting magnetic field displays propagating wave-like behavior. This behavior can be modelled in terms of an αΩ dynamo. In most cases super-equipartition fields are generated. By varying the fraction of helicity of the turbulence the regeneration of poloidal fields via t...

Forced Turbulent Shear Layer

Overview of turbulent shear flows

A brief review of basic concepts and folklore in shear turbulence. 1 Reynolds decomposition Experimental measurements show that turbulent flows can be decomposed into welldefined averages plus fluctuations, v = v̄ + v′. This is nicely illustrated in the Turbulence film available online at http://web.mit.edu/hml/ncfmf.html that was already mentioned in Lecture 1. In experiments, the average v̄ is ...

Cfd-based Modelling of Bubble-particle Collision Efficiency with Mobile Bubble Surface in a Turbulent Environment

Flotation modelling to date appears to have concentrated either on macroscale processes or on ideal microscale processes – there has been no attempt to integrate detailed models at different scales. In this paper, bubble-particle collision efficiency with mobile bubble surfaces in a turbulent flow is investigated from a multiscale modelling viewpoint and a general methodology for modelling of t...