Investigating the Effect of Reynolds Number on Non-Newtonian Fluid-Hammer in Laminar Flow

In the present study, the sensitivity of the behavior of an Upper-Convected-Maxwell polymer and an Oldroyd-B fluid are compared to a Newtonian fluid. The governing equations are the Navier - Stokes equations and viscoelastic fluid equations. These equations are non-dimensionalized and it is found that Reynolds and Mach numbers are only the dimensionless parameters that exists in all three mentioned fluids. The viscosity of fluids as a friction factor causes that Reynolds number and its changes play an important role in the oscillations and also the attenuation of the fluid transient during Fluid hammer phenomenon. The numerical method used is a two-step variant of the Lax-Friedrichs (LxF) method. The results show that the viscoelastic properties of fluids, such as the non-linear relationship of stress and strain, relaxation time and …, reduce their variability compared to Newtonian fluid. Finally, the maximum sensitivity to Reynolds variations in Newtonian fluid and the minimum amount is observed in the Upper-Convected-Maxwell polymer that there are strong viscoelastic properties in its equations.