Supervision: Stanislav Sergeev

Project type: Semester project (master) Master thesis


The development of novel noise reduction technologies is challenged by the growing environmental noise pollution concerns. Since conventional passive noise control materials (porous medium, resonators, etc) are almost incapable to achieve broadband performance and be effective at low frequencies, active noise control techniques raise a high research interest. Most of active solutions utilize conventional electrodynamic loudspeakers as a controlled transducer. However, the suitability of such technology can be disputable in certain situations. In environments presenting extreme climatic conditions, the membrane of conventional loudspeakers may appear a fragile part. Also, the overall weigh of the active system may appear unacceptable for aircraft applications. Therefore, active noise control would benefit from alternative transducers.

We are currently working on the development of a plasma-based electroacoustic transducer, which can potentially satisfy most of the requirements of aircraft engine noise reduction. The actuator is based on the atmospheric corona discharge principle. Through a direct ionization of the bulk of air between the electrodes it is possible to control the movement of charged particles by changing electrical field magnitude. With a certain electrical signal sound waves can be generated. With plasma technology, the actuator does not require any fragile moving parts, has non-resonant response, is lightweight and simple in construction. In our recent studies we demonstrated that this actuator provides several advantages over conventional transducers and can be suitable for active noise control applications.

One important improvement track is the increase of the acoustic output power of such transducers. The current prototype produces a sound pressure level of 70 dB at 1 m distance at 1 kHz. This project is devoted to the development and implementation of approaches to outperform existing actuator.

The workflow of the project is as follows:

  • Review existing literature and identify possible directions on sound power improvement

  • Work out a theoretical concept of the actuator design modification

  • Try out the concept in the numerical simulation. The idea is to work on the existing COMSOL model of the actuator and verify the performance of the modifications

  • Manufacture a prototype and conduct a full acoustic assessment of the transducer

Profile: Electrical engineering, Physics, Mechanics

Prerequisites: Acoustics

Learning outcomes: linear acoustics, acoustic measurements, COMSOL programming

Context: Theory/Physical Simulations (50%), measurements (50%)