Characterization of turbulent jets from high-aspect-ratio rectangular nozzles

Turbulent free jets issuing from rectangular slots with various high aspect ratios (15-120) are characterized. The centerline mean and rms velocities are measured using hot-wire anemometry over a downstream distance of up to 160 slot heights at a slot-height-based Reynolds number of 10000. Experimental results suggest that a rectangular jet with sufficiently high aspect ratio (> 15) may be distinguished between three flow zones: an initial quasi-plane-jet zone, a transition zone, and a final quasi-axisymmetric-jet zone. In the quasi-plane-jet zone, the turbulent velocity field is statistically similar, but not identical, to those of a plane jet. (c) 2005 American Institute of Physics.

Capillary network models for transport in packed beds: Considerations of pore aspect ratio

The conventional analysis for the estimation of the tortuosity factor for transport in porous media is modified here to account for the effect of pore aspect ratio. Structural models of the porous medium are also constructed for calculating the aspect ratio as a function of porosity. Comparison of the model predictions with the extensive data of Currie (1960) for the effective diffusivity of hydrogen in packed beds shows good agreement with a network model of randomly oriented intersecting pores for porosities upto about 50 percent, which is the region of practical interest. The predictions based on this network model are also found to be in better agreement with the data of Currie than earlier expressions developed for unconsolidated and grainy media.

A Neglected Aspect of Business: Human and Social Capital in the Sri Lankan Tea Plantations

This paper examines idiosyncrasies of tea plantation culture and politics in relation to Sri Lankan national and popular cultural typologies, with special reference to female tea plantation workers. Tea production in Sri Lanka is heavily based on manual labour, and it is the largest industry that provides accommodation for employees and their families. In this paper, it is argued that politico-cultural production relations have dominated labour productivity in tea plantations. Ways in which female workers have been marginalized, through patriarchal politics, ethnicity, religion, education, elitism, and employment are explained. This culture of the plantation community operates negatively with respect to the management agenda. It is also argued that social capital development in tea plantations is important not only for productivity improvement, but also for reasons of political and social obligation for the nation, because migrant plantation workers have been working and living in plantations over 150 years.