Dear Sir,nThank you a lot for your kind help,nI have tried to patch the pressure in the Helium Zone as you said as follow:nHowever, when I checked the pressure of the Helium zone, it seems the pressure does not change.nCould you please tell me how to fix this problem?nBtw, regarding the viscosity, please suggest to me which model is suitable for my problem? Laminar or k-epsilon?nThank you,