Turbulence measurements in pipe flow using a nano-scale thermal anemometry probe

A new nano-scale thermal anemometry probe (NSTAP) has been developed using a novel procedure based on deep reactive ion etching. The performance of the new probe is shown to be superior to that of the previous design by Bailey (J Fluid Mech 663:160-179, 2010). It is then used to measure the streamwise velocity component of fully developed turbulent pipe flow, and the results are compared with data obtained using conventional hot-wire probes. The NSTAP agrees well with the hot-wire at low Reynolds numbers, but it is shown that it has better spatial resolution and frequency response. The data demonstrate that significant spatial filtering effects can be seen in the hot-wire data for probes as small as 7 viscous units in length.