7-11 July 2014
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=16&confId=34"><font color=#0000ff>SAIP2014 Proceedings published on 17 April 2015</font></a>

Axial Segregation in Rotating Drum - Extension of the Basic Axial Diffusion Model

9 Jul 2014, 11:50
20m
D Les 103

D Les 103

Oral Presentation Track F - Applied Physics Applied

Speaker

Mr Elbasher Mohamed Elbasher Ahmed (University of Cape Town)

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

Yes

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD)?

PhD

Main supervisor (name and email)<br>and his / her institution

Dr Indresan Govender
Applied Physics Group, Department of Physics, University of Cape Town, P/Bag Rondebosch, 7701

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

In the last two decades, two mechanisms for describing axial segregation in granular mixtures have emerged in the context of binary mixtures. While the transient travelling wave picture has been well established, it lacks the physical connection to the well known friction hypothesis: Granular material composed of different frictional properties diffuse
(into axial bands) due to concentration fluctuations in the free surface layer caused by friction-limited mobility. In this paper we present an extension to the frictional mechanism based on free surface flow by extending the axial gradient operator to second order in a binomial expansion. Moreover, we have replaced the idealised Newtonian shear stress with a more realistic Bagnoldian-type that is well known to describe inertially dominated flows like that observed (via Positron Emission Particle Tracking experiments) in the free surface layer. The validity of the new model is illustrated in the successful reproduction of axial segregation and banding, and the subsequent coarsening that is experimentally observed with time evolution.

Primary author

Mr Elbasher Mohamed Elbasher Ahmed (University of Cape Town)

Co-author

Dr Indresan Govender (University of Cape Town)

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