Relevance of visco-plastic theory in a multi-directional inhomogeneous granular flow P.-P. Cortet, D. Bonamy, F. Daviaud, O. Dauchot, B. Dubrulle and M. Renouf EPL, 88 1 (2009) 14001 Published online: 21 October 2009 DOI: 10.1209/0295-5075/88/14001