The time-varying nature of the asymmetrical flow of a shear-thinning polymer solution in transitional pipe flow.
Chaofan Wen, Robert Poole, David Dennis
Session: Instability and Transition 5
Session starts: Thursday 27 August, 10:30
Presentation starts: 10:45
Room: Room A
Chaofan Wen (University of Liverpool)
Robert Poole (University of Liverpool)
David Dennis (University of Liverpool)
Previous studies of shear-thinning fluids in pipe flow discovered that, although the time-averaged velocity profile was axisymmetric when the flow was laminar or fully turbulent, contrary to expectations it was asymmetric in the laminar-turbulent transition regime. The general consensus of these previous experiments was that the location of the peak velocity remained at a fixed point in space. We present new experimental data which demonstrates that this is in fact not the case. Our results confirm the significant departures from axisymmetry in transitional flows of shear-thinning fluids, in addition to the observation that the asymmetric flow pattern is not stationary, the peak velocity is seen to preferentially arise at certain azimuthal locations.