Multiarray Micromachined Probe for Turbulence Measurements Assembled of Suspended Hot-Film Sensors

To meet the need to access experimentally the full tensor of velocity derivatives at smallest scales of turbulent flows, we developed, fabricated, and tested an out-of-plane micromachined hot-film sensor that has a suspended 100-nm thick sensing element. We present a unique multiarray hot-film probe as an assembly of five arrays of four sensors each. Experimental results demonstrate the improved resolution of the sensor compared with a conventional hot-wire and to a nonsuspended version of such a sensor. A simple and clear method for sensor spatial resolution evaluation is also discussed.