Performance studies of the constant voltage anemometer in a Mach 2.3 boundary layer

Abstract

The operational features of the Constant Voltage Anemometer (CVA) are shown to be well adapted for measurements in supersonic flows. The time constant of hot-wire under constant voltage operation is verified to be much smaller than that under constant current operation. Good noise immunity feature of the constant voltage operation with large bandwidth of the CVA circuit were also noticed from the experiments. An extensive investigation has been conducted in a Mach 2.3 boundary layer. The software compensation approach described in an earlier study is again applied to the data in the present experiments. The approach of compensating the CVA for the hot-wire time constant partially with hardware during the experiment and later correcting the CVA output with the actual in-situ measured time constant has produced consistently good results with an increased bandwidth. The turbulence levels estimates deduced from CVA data collected at different wire overheats agree well with earlier published results. Comparisons with the Constant Current Anemometer (CCA) and the Constant Temperature Anemometer (CTA) were conducted in the same experimental conditions.