About the inlet and outlet

Hi everyone. As shown in the figure, the gas outlet(BC_3) and solid inlet(BC_4) are on the top of the domain. The gas inlet(BC_2) and solid outlet(BC_5) are on the bottom of the domain. It run unsuccessfully. Maybe the (BC_3) overlap with (BC_4) and the (BC_2) overlap with (BC_5)? If it is, how can I set the inlet and outlet for counter flow between gas and solid as shown in figure. Thanks.

You cannot stack flow boundary conditions. What you are trying to do isn’t supported.

Thank you. I got it.