Multi-sensor hot wire anemometry
Turbulent flows are characterized by the presence of fluctuating vorticity. This is a key feature that distinguishes turbulence from other stochastic fluid motions. Direst measurements of the velocity gradients and the components of the vorticity vector, with high time and space resolution, can be accomplished with the use of multisensory Hot Wire Anemometry (HWA). LAT/UP has developed a 12-wire probe for this purpose.
The in-house manufactured probe consists of three 4-wire arrays in triangular arrangement. Sensing wires 2.5 μm in diameter and 0.5 mm in length are orientated at 45° to the streamwise direction. They are operated in CTA mode and the data reduction is accomplished using a look up table method. The probe measures simultaneously all three velocity vector components at the centroids of each 4-wire array on a cross plane of the flow field. Velocity derivatives are estimated using a first order, forward difference scheme.
Front view of the 12-wire HWA probe
Cavo, A., Lemonis, G., Panidis, Th., Papailiou, D.D., 2007, Performance of a 12-sensor vorticity probe in the near field of a rectangular turbulent jet, Experiments in Fluids, 43 (1), pp. 17-30
Romeos, A., Lemonis, G., Panidis Th., Papailiou D. D., 2009, Multisensor hot wire vorticity probe measurements of the formation field of two co rotating vortices, Flow Turbulence Combust, 83, pp. 153-183
Bauer K., Panidis Th., Schmid U., Seidel H. (2010) Strömungs – oder Wirbelmessfühler (Micromachined Multi-Hot-Wire Vectorial Flow and Vorticity Probe), German Patent (EADS Deutschland GmbH, University of Patras): DE102008020874B4