Hi I am using MPPICFoam,I am simulating a riser of circulating fluidised bed. Which consists of cylindrical geometry Inlet at the bottom,Outlet at top and circular wall. In which I have first distributed the particle by using injectionModel of type manualinjection and difined the particle positions initially. Now,What I have to do is insert the same number of particles in the inlet patch which is coming out of the Outlet patch. I searched and found that by using multiInteraction we can apply multiple patchintraction models at a time.I applied the multiInteraction patch intraction model as per the instruction in PatchInteractionModel.H but found following error. ----------------------------------------------------------------------------------- Unknown patch interaction model type coincidentBaffleInteraction Valid patch interaction model types are: 5 ( localInteraction multiInteraction none rebound standardWallInteraction ) ---------------------------------------------------------------------------------- Can anybody tell what is coincidentBaffleInteraction. Or how to apply cyclic type boundary condition for the particle phase onle by using this this patch intraction type. Suraj