LeiQaS

Official Project Name: "Quiet Transverse Thrusters – Reducing the Sound Emission of Transverse Thrusters with Methods of Active Vibration Reduction“

Project Duration: December 1, 2020 – November 30, 2023

Business Area: Mechanical Engineering

______________________________

The LeiQaS project (Quiet Transverse Thrusters) aimed to minimize the noise emissions from transverse thruster systems (TTS) impacting ships and the maritime environment through innovative vibration reduction technologies. The primary goal was to reduce structure-borne and underwater noise to meet increasing environmental, occupational safety, and onboard comfort demands. As part of this project, Wölfel Engineering developed an active vibration absorber unit that significantly reduces TTS noise emissions through precise vibration control.

Project objective and description

The LeiQaS project focused on significantly reducing the noise emissions of transverse thruster systems into ships and the maritime environment through active structure-borne noise reduction contributing to environmental protection and increased onboard comfort. Wölfel Engineering’s subproject concentrated on developing an active vibration system for reducing structure-borne noise.

Transverse thruster systems (TTS) are increasingly used to improve ship maneuverability, particularly at low speeds and under demanding conditions. However, they generate significant noise emissions caused by vibrations and sound, affecting both the ship's surroundings and the maritime environment. This has led to growing interest in developing low-noise TTS solutions that comply with environmental protection standards, workplace safety, and modern comfort requirements.

2024-11-LeiQaS-Websiteinhalt — Experimental test setup (Wölfel, University of Rostock, Jastram, Promarin, Schiffbau-Versuchsanstalt Potsdam)

The LeiQaS project combined various innovative approaches to reduce TTS noise, including optimized propeller designs, measures to minimize cavitation, and active vibration reduction. These aspects were addressed by a consortium of experts in fluid dynamics, propeller development, and structural dynamics. A key component was Wölfel Engineering's subproject, which focused on active vibration reduction to mitigate structure-borne noise and reduce its impact on the ship itself.

Within the subproject, Wölfel developed a unit for active vibration isolation and reduction capable of targeting vibrations caused by propeller blade passages. Comprehensive structural dynamic analyses using finite element methods (FEM) and multi-body simulations (MBS) were performed to model the system's dynamic properties and identify optimal vibration reduction parameters.

The developed models and algorithms were validated through experimental tests under realistic conditions during large-scale trials. These trials demonstrated that the active absorber unit achieved significant vibration reductions in TTS through precise actuator control, achieving horizontal vibration level reductions of up to 10 dB. These successes underscore the effectiveness of the developed technology and its potential application on modern ships.

Upon project completion, Wölfel Engineering presented a significant innovation in noise control that could be integrated into market-ready systems to meet the demands for low-noise and environmentally friendly ship propulsion.

Results

The project successfully demonstrated the ability to reduce noise through active vibration reduction. The developed systems measurably decreased TTS vibrations. Horizontal configurations achieved vibration reductions of up to 10 dB. The results highlight the potential for developing market-ready, low-noise propulsion systems for maritime applications. The simulations and experimental outcomes provide valuable insights for future designs in the maritime sector and beyond.