Corrections of dual-wire CTA data in turbulent swirling and non-swirling jets

Abstract

Constant Temperature Anemometers provide opportunities for high data rate in relation to velocity and turbulence measurements in gaseous jets. The application of dual-wire probes in turbulent non-swirling and swirling jets is, however, challenging due to the need to correct for directional responses, velocity gradients and probe misalignments with the mean flow direction. Although swirl flow measurements have been conducted in the past using dual-wire probes, the literature does not include clear methodologies to compensate for both gradient effects and changes to the mean flow direction, particularly in flow regions with high shear and strong swirl over a range spanning (S=0–1.05). As a result, this paper presents an overview of the methodology needed to apply dual-wire probes and accommodate changes to the resultant velocity (mean flow) angle (α) through orienting the probe (ψ). Results show that both velocity gradient effects as well as probe misalignments are strongly affected by radial location, Reynolds number and swirl intensity. This study demonstrates a setup methodology that orients CTA X-wire probes for improved data yield and accuracy for turbulent swirling jets.