[arash.mp]

hi every one.
i have a problem in fluent! i have a multi-layer pipe in which there is a core pipe and some porous pipes surround the core pipe! i want to simulate this in 2D-axisymmetric (fluent 18).
my problem has 2 different densities( 1 density in core pipe and another density in porous layers! this is the case that really happens in my problem) .
i have to collect data from the interface between core pipe and the first layer of porous pipe! but fluent interpolates the density(and viscosity) at the interface that make my answers wrong! how can i fix this???
(also fluent change the WSS at the interface because of the difference between the values of WSS in 2 domains)
also i checked the zone id of the interfaces and figured out that the zone id of each interface is the mean value of zone_ids of two adjacent zones!!!!!
i attached a jpeg image of the situation.
thanks