Wind Tunnel International 2009

Page 73

MICROFLOWN

A miniature version of a 3D vector probe, shown with a match head for sizing

Furthermore, the Microflown sensor is linear, whereas a single hotwire cools down with the square root of the velocity. Also, the performance of the Microflown sensor only depends upon the temperature difference whereas a hot wire is sensitive to the ambient temperature itself. Fourth, but not least, the sensitivity of the Microflown is much higher than a single wire solution (detection range goes down to 10nm/s).

Simultaneous aerodynamic and aero acoustic testing Sound-intensity-based measurements based upon PU or USP probes can be carried out in non-anechoic conditions. This sheer fact enables operators of non-anechoic wind tunnels, the far larger part of the total installed facility base, to combine aerodynamic and aero acoustic testing in closed-section wind tunnels. Apart from the obvious efficiency gains, better consistency in datasets is also an important merit.

Products One or three Microflown particle velocity sensors can be combined with a sound pressure transducer, resulting in a range of one (=PU) and three dimensional sound probes (=USP) that can be used under a variety of wind tunnel operating conditions. 2009 | WIND TUNNEL INTERNATIONAL

Wind-tunnel-relevant developments Targeting the wind-tunnel-testing markets, several developments took place during recent years in the Netherlands at various national institutes. 73


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