Bluff Body Drag Control using Synthetic Jet

Abstract

The paper presents the results of an experimental investigation wherein the bullet form drag force as a function of oscillating actuator frequency, various voltage and for different orifice/slot configuration are studied. In order to perform the experiment, an axisymmetric bullet shape model with ellipsoidal nose was used in wind tunnel. The synthetic jet actuator was used to flow control at sharp cut end. The experiment was conducted in a wind tunnel with a working diameter of 1000 mm and a maximum velocity of 45 m/s. The measurements were carried out for the Reynolds number from 88000 to 352000 and for relatively large Strouhal numbers up to St = 4.5 based on model external diameter and free stream velocity. While synthetic jet was switched on, drag coefficient has been reduced by -6% and increased by +22% in relation to the case with the synthetic jet was switched off. The synthetic jet has more impact for relatively low free stream velocity and for single axisymmetric orifice.

Keywords

• Synthetic jet; Zero-net-mass-flux; Drag; Bluff body; Bullet shaped body.