When I apply the boundary conditions, I want to change the values on the wall which constructed the slip boundary condition. I need to write another function “BaseAdvectionBCInters”, but I don’t understand how to calculate _scal_lhs, _mag_pnorm_lhs, _norm_pnorm_lhs in the “BaseAdvectionBCInters”. Then I can use my method to calculate the corresponding value.

And is there anyone use pyfr to simulate reacting flow? Whether there are relevant papers.

It sounds like you want to create your own BC type. Then you can write the BC kernel function to produce any results you like. A good reference point is the implementation of the existing conditions.

Whether the right-hand view matrix is the divergence of the flux at the right hand side of Eq. (2.18)?
and the left-hand view matrix is the divergence of the flux at the left hand side of Eq. (2.18)? If so, for the BC interface, why only have LHS state?

And what’s the mean of _scal_lhs , _mag_pnorm_lhs , _norm_pnorm_lhs?