For the answers: (1) I am not very familiar with the implicit/explicit LES, I am very new to LES... (2) I see the description should be what you have pointed out here, but when I look at the code, it seems that owndelta is replaced by neiDelta if neiDelta > maxDeltaRatio * ownDelta. But as the description says, I think neiDelta should be replaced by maxDeltaRatio * ownDelta. I have replied to you in the #726377664213942323 module... Many thanks....