Discretization error

HDAB

Hello! We are simulating a pipe flow in cfx5.6 and we want to calculate the discretization error. The mesh that we are using is surface mesh with an inflated boundary. To calculate the discretization error we want to get solutions for different mesh qualities. To get these different mesh qualities we are told that we are only suppose to change one mesh parameter. The problem is however, if we only change the the surface mesh max edge length the element volume ratio in the transition between the inflated boundary and the core mesh becomes large. We are considering changing the inflated boundary too, but we are not sure how. Can anyone tell us how to change the mesh?