DETERMINATION OF TRANSITION ONSET IN LAMINAR PULSATILE PIPE FLOWS

This paper presents a program devised in LabView 2009SP1 (R) for the detection of the transition onset in laminar pulsatile pipe flows. As a conclusion of a comprehensive literature survey, it is deduced that there is no well-defined detection program even a methodology for determination of transition onset besides of conventional methods of visual observation on velocity waveforms. The operation of the program which is an original contribution to literature is introduced giving sample plots in the range of time-averaged Reynolds number of 1019 +/- 35 <= Re-ta <= 4817 +/- 164, oscillating Reynolds number of 107 +/- 4 <= Re-os <= 4261 +/- 145, velocity amplitude ratio of 0.05 +/- 0.0017 <= A(t) <= 0.96 +/- 0.03 and Womersley number of 2.72 <= root omega' <= 32.21. As an original contribution to the available literature, two different flow maps that identify the border between laminar flow and transition onset in pulsatile pipe flow in terms of Re-ta=Re-ta(Re-os) and Re-ta=Reta(root omega') are introduced in the covered experimental ranges.