Effects of frequency and amplitude of oscillation on low Reynolds number pulsating flow in a circular pipe

This paper presents studies on low Reynolds number pulsating flow in a circular pipe. The Navier‐Stokes equations expressed in terms of primitive variables on a clustered staggered grid were solved. A block tridiagonal algorithm coupled with cyclic reduction techniques was used to reduce computation effort. The effects of frequency on the amplitude of the fluctuating axial velocity are confined mainly to the wall region. The effects due to changes in frequency parameter are insignificant near the inlet region. The amplitude of pulsating axial velocity changes from inlet to the fully developed region by about 10% whereas for the time mean velocity, the amplitude almost doubles. It was observed that flow reversal begins at the pipe inlet section when the amplitude of oscillation is equal or greater than 1.0 and in the developing region, flow reversal would occur when the amplitude factor is greater than the critical amplitude factor.