Numerical Study of Impulsive Motion Past a Rotating Cylinder for Newtonian and Non-newtonian Fluid

The flow phenomena for a rotating cylinder with the application of an impulsive translational motion is studied using ANSYS FLUENT 19R3. The study is carried out for power-law index n = 1 and 2 at a fixed Reynolds number (Re = 40) for different non-dimensional rotation rates ( \(\alpha\)  = 0.5, 1, 2). After the initial flow field reaches a steady state, the impulsive motion is applied by implementing a User defined function (UDF) which assigns a zero-inlet velocity. The time evolution of vorticity contours provides insights into the developing flow field after the impulsive motion. For both the power indices, it has been found that a higher rotational rate leads to faster flow stabilization and can be used for flow control. The flow phenomena is studied quantitatively in terms of aerodynamic coefficients. The Drag coefficient value decreases by 36.47% as value of \(\alpha\) increases from 0.5 to 2 for n = 1. The sudden variation in force coefficients and their subsequent variation is used to interpret the effect of rotation rate on the disturbed flow field due to impulsive motion.