TRANSITION FROM LAMINAR TO TURBULENT-FLOW OF WATER IN A PIPE MEASURED BY A PULSED NMR METHOD

The transition from the laminar flow to the turbulent flow of water in a long circular pipe has been studied by observing the spin echo amplitudes in a pulsed NMR method. The spin echo signal is characteristic to the flow condition, i. e. , its amplitude is large when the flow is laminar, while it is small when the flow is turbulent. In the transition region spin echo signals with large amplitudes and those with small amplitudes appear intermittently. The intermittency factor of the flow has been measured in the transition region. This experiment shows that the pulsed NMR method might be useful to study dynamical characters of the transition region.