  We study time-dependent density segregation of granular mixtures flowing over
an inclined plane. Discrete Element Method (DEM) simulations in a periodic box
are performed for granular mixtures of same size and different density
particles flowing under the influence of gravity. In addition, a continuum
model is developed to solve the momentum balance equations along with species
transport equation by accounting for the inter-coupling of segregation and
rheology. The particle force-based density segregation theory has been used
along with the $\mu-I$ rheology to predict evolution of flow properties with
time for binary and multicomponent mixtures. The effect of particle
arrangements on the transient evolution of flow properties for three different
initial configurations is investigated using both continuum and DEM
simulations. Continuum predictions for various flow properties of interest such
as species concentration, velocity, pressure, and shear stress at different
time instants are compared with DEM simulations. The results from the discrete
and continuum models are found to be in good agreement with each other for
well-mixed and heavy-near-base initial configurations. However, the continuum
model is unable to predict the flow evolution for the light-near-base initial
configuration. DEM simulations reveal the presence of an instability driven,
quick segregation for this configuration which is not predicted by the one
dimensional model and requires generalization to three dimensions.
