TRAINING CENTER FOR EXPERIMENTAL AERODYNAMICS RHODE-SAINT-GENESE (BELGIUM)
A new technique for the measurement of small forces or other low level effects has been developed at the VKIFD low density wind tunnel. Measurement of forces as low as 10 micrograms appear feasible using ferroelectric transducers in conjuction with a low level tuned amplifier system and synchronous demodulator. This performance is made possible by periodically screening the flow on the model or even chopping the full flow of the wind tunnel by means of a mechanically actuated screen. Such modulation techniques, which result in considerable noise and drift reduction because of the narrow band width of a system using synchronous demodulation are of course widely used for the measurement of low level DC signals as well as detection of weak radiation, molecular beams, biological phenomena, etc. Author
Presented at the Semi-Annual Supersonic Tunnel Association Meeting (22nd) held at the von Karman Institute for Fluid Dynamics, Rhode-Saint-Genese, Belgium, 24-25 Sep 64.