Experimental study of a vertical column of grains submitted to a series of impulses G. Lumay, S. Dorbolo, O. Gerasymov and N. Vandewalle Eur. Phys. J. E, 36 2 (2013) 16 Published online: 20 February 2013 DOI: 10.1140/epje/i2013-13016-1