Slatter, PT, Haldenwang, R & Chhabra, RP 2011, 'The laminar/turbulent transition for paste sheet flow', in R Jewell & AB Fourie (eds), Proceedings of the 14th International Seminar on Paste and Thickened Tailings
, Australian Centre for Geomechanics, Perth, pp. 381-388.
The sheet flow of paste material is of critical importance in tailings disposal, since this is the principal flow mechanism at tailings disposal sites. Furthermore, the sheet flow paradigm for free surface flows has the potential to provide a basis for analysis and design for the open channel flow of mineral tailings suspensions. In our previous studies, we showed that a sheet flow diagram could be constructed, and that it is directly related to the rheogram in a manner analogous to that of Rabinowitsch and Mooney for tube flow. Furthermore we showed that these flows could be scaled for engineering design purposes in a manner similar to the approach of Metzner and Reed for tube flow. Whilst some progress has been made for the rheometrical measurement and analyses of sheet flow, many unresolved issues remain. Arguably, the most acute of these is the location of the Laminar/Turbulent transition. The objective of this paper is to develop and evaluate an approach for the analysis of the Laminar/Turbulent transition of sheet flows. Building on our previous studies, a new Reynolds number approach for sheet flows of general non-Newtonian material is developed and presented. Using experimental data, it is shown that this approach works well for power law fluids, and extension of this approach for the analysis of viscoplastic materials is discussed. Further work involving the role of the yield stress in the transitional flow process is being undertaken.
Chow, V.T. (1959) Open Channel Hydraulics, McGraw-Hill Book Co-Singapore.
Fuentes, R. (2004) Slurry flumes in Chile (Keynote Address), Hydrotransport 16, 16th International Conference on the Hydraulic Transport of Solids in Pipes, Santiago, Chile.
Haldenwang, R. (2003) Flow of non-Newtonian flow in Open Channels, Unpublished D.Tech thesis, Cape Technikon, Cape Town, South Africa.
Haldenwang, R. and Slatter, P.T. (2006) Experimental procedure and database for non-Newtonian open channel flow, Journal of Hydraulic Research, Vol. 44, Issue 2, pp. 283–287.
Haldenwang, R., Slatter, P.T. and Chhabra, R.P. (2002) Laminar and Transitional flow in Open Channels for non-Newtonian Fluids, in Proceedings 15th International Conference on Hydrotransport, Banff, Canada, pp. 755–768.
Metzner, A.B. and Reed, J.C. (1955) Flow of non-Newtonian fluids - correlation of the laminar, transition and turbulent flow regions, AIChE Journal, Vol. 1, No. 4.
Slatter, P.T. (1999) A new friction factor for yield stress fluids, British Hydromechanics Research Group 14th International Conference on Slurry Handling and Pipeline Transport Hydrotransport 14, Maastricht, September, pp. 255–265.
Slatter, P.T., Haldenwang, R. and Chhabra, R.P. (2010) The Sheet Flow Viscometer, Hydrotransport 18, in Proceedings 18th International Conference on the Hydraulic Transport of Solids, BHR Group, Rio de Janeiro, 22–24 September.