PULSED-WIRE ANEMOMETRY

Pulsed-wire anemometry was first developed as a tool for making velocity and turbulence measurements in the late 1960s. It has been continuously refined and its potential exploited by a number of groups who have obtained reliable data in situations where the use of other techniques would have been extremely difficult. The technique is particularly useful in flows of high turbulence intensity and has therefore been used to greatest effect in separated flows. Although its range of applicability is much more restricted than that of laser-Doppler anemometry, it is an order of magnitude cheaper, and it does not require seeding of the flow, with all the attendant uncertainties. First the physical basis of pulsed-wire anemometry is briefly described, and the major sources of experimental error are outlined for cases in which the technique is used both remote from and close to walls. Progress in the design of probes, which have been improved in a number of ways since the early days to reduce errors, is also outlined. The author then reviews the kinds of measurements that have been successfully made and the consequent improvements in the understanding of the physics of complex flows. Examples are drawn from a wide range of work, including some unusual applications like measurements in very low velocity gas mixtures. The paper closes with a summary of the limitations of the technique and an overall assessment of the likely potential for its use in future turbulence research.