The effective of the passive and active techniques on the vibration control system

The interaction between structures and fluid flow in a direction perpendicular to the body can induce vibrations in the structure, a phenomenon known as vortex-induced vibration (VIV). This phenomenon may lead to structural failure due to resonance, which occurs when the natural frequency of the structure matches the vortex shedding frequency. Therefore, it is essential to employ vibration control devices to address the resulting high-amplitude instabilities. In this study, a subsonic wind tunnel with open-circuit specifications was constructed. This open-type wind tunnel generates airflow at varying velocities through the test section. To control vibrations around the cylindrical pipe, an Open-Loop Active Vibration Control (OLAVC) system is proposed. This system utilizes dual control rods, made of hollow stainless steel, driven by two DC motors positioned at the upper and lower sides of the main cylindrical pipe, referred to as the CRBCP (Control Rod-Based Cylinder Pipe). The effectiveness of a passive control strategy was evaluated prior to energizing the DC motors at 12 V. The results indicated that passive control alone was insufficient to adequately suppress the vibrations of the cylinder pipe. Subsequently, the OLAVC procedure was implemented using several voltage levels—12 V, 10 V, 8 V, and 6 V—corresponding to 100, 83, 75, and 50% of motor power, respectively. The OLAVC system proved effective in reducing vibrations across all actuator configurations. The maximum suppression, reaching 79.05%, was achieved at a motor voltage of 12 V and a rotational speed of 2349 rpm.