Contrôle de la propagation des ondes vibro-acoustiques dans les tuyaux à partir de tours noirs acoustiques // Vibroacoustic control of fluid-filled pipes with add-on acoustic black holes

The propagation of noise and vibrations in hydraulic systems is a critical issue across numerous industrial sectors, including building services, energy, and aerospace. Noise sources are primarily linked to hydraulic pumps generating pressure pulsations in the circuit. Structural vibrations can lead to mechanical fatigue, particularly at pipe junctions, with potentially serious consequences for the operation and safety of hydraulic installations. Furthermore, acoustic waves propagating inside the pipe can be a source of noise disturbance, especially in building-related applications. Developing effective devices to control the propagation of vibrations and acoustic waves in pipes is therefore of primary importance.
The Acoustic Black Hole (ABH) concept [1] appears as a promising approach in this context. It has been investigated in laboratory settings by various research groups over the past decade. Through specific geometric design, the ABH aims to slow down wave propagation and concentrate energy in a specific zone where it can be dissipated as heat through thermoviscous or viscoelastic effects. Two main types of ABH exist:
- Structural ABHs slow down the propagation speed of flexural waves by reducing the thickness of a structure according to a power-law profile, with a viscoelastic element added at the tip to promote energy dissipation.
- Sonic ABHs [4, 5] slow down acoustic wave propagation using a system of concentric rings with progressively smaller apertures; absorbing materials at the termination or micro-perforated panels are used to enhance thermoviscous losses.
While existing literature on ABHs largely focuses on applications in air — including sonic black holes in air-filled ducts [2, 3] and structural ABHs embedded in beams, plates and shells [4, 5] for vibration damping — the case of hydraulic piping introduces an important additional complexity: a strong fluid-structure coupling between the elastic pipe wall and the heavy internal fluid [6]. Depending on the frequency range and the circumferential modes involved, vibroacoustic energy can be distributed between structural and acoustic medium in ways that differ fundamentally from the light-fluid case.
In this context, this thesis proposes to study the impact on vibroacoustic wave propagation of ABH devices mounted on a heavy fluid-loaded pipe. The work will consider structural ABHs attached to the outer surface of the pipe and/or sonic ABHs inserted between two pipe sections.
The research programme is defined as follows:
- realization of a bibliographic review;
- familiarisation with simple models of structural and sonic ABHs;
- development of an analytical model of a fluid-filled cylindrical shell and analysis of propagation modes in function of the frequency range;
- selection of one ABH concept for the following of the study;
- development of numerical vibroacoustic models representing the ABHs coupled to heavy-fluid-filled cylindrical shells (fully finite element models (FEM) or/and hybrid finite element /analytical models);
- parametric analysis of ABH performances on the vibroacoustic propagation as a function of frequency range and circumferential modes;
- experimental validation on a test case in a laboratory (during the 6 months secondment in Grundfos, a pump manufacturer);
- writing of the thesis manuscript.
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The propagation of noise and vibrations in hydraulic systems is a critical issue across numerous industrial sectors, including building services, energy, and aerospace. Noise sources are primarily linked to hydraulic pumps generating pressure pulsations in the circuit. Structural vibrations can lead to mechanical fatigue, particularly at pipe junctions, with potentially serious consequences for the operation and safety of hydraulic installations. Furthermore, acoustic waves propagating inside the pipe can be a source of noise disturbance, especially in building-related applications. Developing effective devices to control the propagation of vibrations and acoustic waves in pipes is therefore of primary importance.
The Acoustic Black Hole (ABH) concept [1] appears as a promising approach in this context. It has been investigated in laboratory settings by various research groups over the past decade. Through specific geometric design, the ABH aims to slow down wave propagation and concentrate energy in a specific zone where it can be dissipated as heat through thermoviscous or viscoelastic effects. Two main types of ABH exist:
- Structural ABHs slow down the propagation speed of flexural waves by reducing the thickness of a structure according to a power-law profile, with a viscoelastic element added at the tip to promote energy dissipation.
- Sonic ABHs [4, 5] slow down acoustic wave propagation using a system of concentric rings with progressively smaller apertures; absorbing materials at the termination or micro-perforated panels are used to enhance thermoviscous losses.
While existing literature on ABHs largely focuses on applications in air — including sonic black holes in air-filled ducts [2, 3] and structural ABHs embedded in beams, plates and shells [4, 5] for vibration damping — the case of hydraulic piping introduces an important additional complexity: a strong fluid-structure coupling between the elastic pipe wall and the heavy internal fluid [6]. Depending on the frequency range and the circumferential modes involved, vibroacoustic energy can be distributed between structural and acoustic medium in ways that differ fundamentally from the light-fluid case.
In this context, this thesis proposes to study the impact on vibroacoustic wave propagation of ABH devices mounted on a heavy fluid-loaded pipe. The work will consider structural ABHs attached to the outer surface of the pipe and/or sonic ABHs inserted between two pipe sections.
The research programme is defined as follows:
- realization of a bibliographic review;
- familiarisation with simple models of structural and sonic ABHs;
- development of an analytical model of a fluid-filled cylindrical shell and analysis of propagation modes in function of the frequency range;
- selection of one ABH concept for the following of the study;
- development of numerical vibroacoustic models representing the ABHs coupled to heavy-fluid-filled cylindrical shells (fully finite element models (FEM) or/and hybrid finite element /analytical models);
- parametric analysis of ABH performances on the vibroacoustic propagation as a function of frequency range and circumferential modes;
- experimental validation on a test case in a laboratory (during the 6 months secondment in Grundfos, a pump manufacturer);
- writing of the thesis manuscript.
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Début de la thèse : 01/10/2026

Programmes de l'Union Européenne de financement de la recherche (ERC, ERASMUS)

INSA Lyon

162 MEGA - Mécanique, Énergétique, Génie Civil, Acoustique

Profile: If you recognize yourself in the story below, then you have the profile that fits the project and the research group: • I have a master degree in mechanical engineering, acoustics, physics or mathematics and performed above average in comparison to my peers and I am not in possession of a doctoral degree at the date of recruitment (mandatory requirement) • I haven't had residence or main activities (studies or working position, even remote) in France for more than 12 months in the last 3 years at the date of recruitment (mandatory requirement). • During my courses or prior professional activities, I have gathered some basic experience with the physical principles of structural dynamics and (vibro-)acoustics and the related numerical modeling techniques, such as the Finite Element Method (FEM), as well as numerical optimization, manufacturing methods, and/or I have a profound interest in these topics. Experience with knowledge of metamaterials and passive control of sound and vibration is considered as a bonus. • I am proficient in written and spoken English. • I feel comfortable to work as a team member and I am eager to share my results to inspire and being inspired by my colleagues. • As a Doctoral Candidate I will perform research in a structured and scientifically sound manner. I will read technical papers, understand the nuances between different theories and implement and improve methodologies myself. • Based on interactions and discussions with my supervisors and the colleagues in my team, I will set up and update a plan of approach for the upcoming 1 to 3 months to work towards my research goals. I will work with a sufficient degree of independence to follow my plan and achieve the goals. I will indicate timely when deviations of the plan are required, if goals cannot be met or if I want to discuss intermediate results or issues. • In frequent reporting, varying between weekly to monthly, I will show the results that I have obtained and I will give a well-founded interpretation of those results. I will ABHSSYS Project MSCA-DN 101227712 iterate on my work and my approach based on the feedback of my supervisors which steer the direction of my research. • In the framework of the DN-ABHSSYS project, I will participate to the network training schools and I will present my work progresses in front of the supervisory board every 6 month. • During the course of my PhD, I will be hosted by the industrial partner involved in the thesis for a 6 months secondment in Grundfos, Denmark. • During my PhD I want to grow towards following up the project that I am involved in and representing the research group on project meetings or conferences. I see these events as an occasion to disseminate my work to an audience of international experts and research colleagues, and to learn about the larger context of my research and the research project.
Profile: If you recognize yourself in the story below, then you have the profile that fits the project and the research group: • I have a master degree in mechanical engineering, acoustics, physics or mathematics and performed above average in comparison to my peers and I am not in possession of a doctoral degree at the date of recruitment (mandatory requirement) • I haven't had residence or main activities (studies or working position, even remote) in France for more than 12 months in the last 3 years at the date of recruitment (mandatory requirement). • During my courses or prior professional activities, I have gathered some basic experience with the physical principles of structural dynamics and (vibro-)acoustics and the related numerical modeling techniques, such as the Finite Element Method (FEM), as well as numerical optimization, manufacturing methods, and/or I have a profound interest in these topics. Experience with knowledge of metamaterials and passive control of sound and vibration is considered as a bonus. • I am proficient in written and spoken English. • I feel comfortable to work as a team member and I am eager to share my results to inspire and being inspired by my colleagues. • As a Doctoral Candidate I will perform research in a structured and scientifically sound manner. I will read technical papers, understand the nuances between different theories and implement and improve methodologies myself. • Based on interactions and discussions with my supervisors and the colleagues in my team, I will set up and update a plan of approach for the upcoming 1 to 3 months to work towards my research goals. I will work with a sufficient degree of independence to follow my plan and achieve the goals. I will indicate timely when deviations of the plan are required, if goals cannot be met or if I want to discuss intermediate results or issues. • In frequent reporting, varying between weekly to monthly, I will show the results that I have obtained and I will give a well-founded interpretation of those results. I will ABHSSYS Project MSCA-DN 101227712 iterate on my work and my approach based on the feedback of my supervisors which steer the direction of my research. • In the framework of the DN-ABHSSYS project, I will participate to the network training schools and I will present my work progresses in front of the supervisory board every 6 month. • During the course of my PhD, I will be hosted by the industrial partner involved in the thesis for a 6 months secondment in Grundfos, Denmark. • During my PhD I want to grow towards following up the project that I am involved in and representing the research group on project meetings or conferences. I see these events as an occasion to disseminate my work to an audience of international experts and research colleagues, and to learn about the larger context of my research and the research project.