  We show that the interparticle friction coefficient significantly influences
the flow and jamming behavior of granular materials exiting through the orifice
of a two-dimensional silo in the presence of another orifice located in its
vicinity. The fluctuations emanating from a continuous flow through a larger
orifice results in an intermittent flow through the smaller orifice consisting
of sequential jamming and flowing events. The mean time duration of jammed and
flow events, respectively, increase and decrease monotonically with increasing
interparticle friction coefficient. The frequency of unjamming instances
($n_{u}$), however, shows a nonmonotonic behavior comprising an increase
followed by a decrease with increasing friction coefficient. The decrease on
either side of the maximum, then, represents a system moving progressively
towards a permanently jammed or a permanently flowing state. The overall
behavior shows a systematic dependence on the interorifice distance which
determines the strength of the fluctuations reaching the smaller orifice
leading to unjamming instances. The probability distributions of jamming and
flowing times are nearly similar for different combinations of friction
coefficients and interorifice distances studied and, respectively, exhibit
exponential and power-law tails.
