I am modelling a open-ended shock tube flow in Fluent in axi-symmetric form. I am calculating impulse inside the shock tube . I am only considering the positive impulse (that is up to the time when pressure is not below ambient pressure). I am using two different models one is inviscid another is laminar. In case of laminar I am getting slightly more impulse. In laminar case, in the pressure profile there is fluctuations which is cause for more value of impulse. So I want to ask whether I am right or something went wrong?