Figure 2 - Impact of liquid volume fraction and drum width on stability.
From the following article
Maximum angle of stability of a wet granular pile
Sarah Nowak, Azadeh Samadani and Arshad Kudrolli
Nature Physics 1, 50 - 52 (2005)
doi:10.1038/nphys106
a, Measured surface angles as a function of Vf of silicone oil (
=5 cS, r=0.5 mm, 
=0.028 r.p.m.).
b, 
m is observed to decay exponentially as W is increased. An error bar is indicated on one of the points (Vf=8
10-3, fitting parameters a0=23.3°, b0=0.33 cm-1, c0=30°).
