Numerical study on the decay and amplification of turbulence in oscillatory pipe flows

Kurzfassung

Results of three-dimensional direct numerical simulations of oscillatory pipe flows at two high Wo 2 f13;26g are presented and discussed. Starting from a fully-developed turbulent velocity field, the flows either relaminarise or reach a conditionally or fully turbulent state, depending onWo and Re. Analysing the temporal and phase-averaged evolution of several quantities, reveals considerably different behaviour of the wall shear stress and the RMS velocity profiles, while the integral bulk flow only reflects minor differences. Furthermore, utilising two different initial conditions do not significantly influence the developing oscillatory bulk flow.