  We report a robust fabrication method for patterning free-standing Pt
nanowires for the use as thermal anemometry probes for small-scale turbulence
measurements. Using e-beam lithography, high aspect ratio Pt nanowires (~300 nm
width, ~70 $\mu$m length, ~100 nm thickness) were patterned on the surface of
oxidized silicon (Si) wafers. Combining precise wet etching processes with dry
etching processes, these Pt nanowires have been successfully released
free-standing between two silicon dioxide (SiO2) beams supported on Si
cantilevers. Moreover, the unique design of the bridge holding the device
allowed to release the device gently without damaging the Pt nanowires. The
total fabrication time was minimized by restricting the use of e-beam
lithography to the patterning of the Pt nanowires while standard
photolithography was employed for other parts of the devices. We demonstrate
that the fabricated sensors are suitable for turbulence measurements when
operated in a constant-current mode. A robust calibration between output
voltage and fluid velocity was established over the velocity range from 0.5 m
s-1 to 5 m s-1 in an SF6 atmosphere at a pressure of 2 bar and a temperature of
21{\deg}C. The sensing signal from the nanowires showed negligible drift over a
period of several hours. Moreover, we confirmed that the nanowires are able to
withstand high dynamic pressures by testing them in air at room temperature
velocities up to 55 m/s.
