NMR IMAGING OF TURBULENT STRUCTURE IN A TRANSITIONAL PIPE-FLOW

One-shot NMR imaging with a very short data acquisition time (approximately 20 ms) is used to reveal the structure of a turbulent equilibrium puff in a transitional pipe flow. Longitudinal vortices in the downstream region of a puff are very clearly visualised in the NMR images. The structure of a puff derived from the images agrees with that suggested by a flow visualisation experiment done previously. The present study demonstrates that one-shot NMR imaging is a very powerful tool in visualising large-scale coherent structures in turbulent flow. © 1990 IOP Publishing Ltd.