Université de Sherbrooke, Département de génie mécanique, Sherbrooke, Québec, J1K 2R1, Canada
Marc-André Guy, Département de génie mécanique, Université de Sherbrooke
Kamal Kesour, Innovation Maritime, Rimouski, QC, Canada
Jean-Christophe G.Marquis, Innovation Maritime, Rimouski, QC, Canada
Giuseppe Catapane, University of Naples Federico II, Naples, Italy
Giuseppe Petrone, University of Naples Federico II, Naples, Italy
Olivier Robin, Département de génie mécanique, Université de Sherbrooke
Popular version of 1pEA6 – Use of metamaterials to reduce underwater noise generated by ship machinery
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026790
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
The underwater noise generated by maritime traffic is the most significant source of ocean noise pollution. This pollution threatens marine biodiversity, from large marine mammals to invertebrates. At low speeds, the machinery dominates the underwater radiated noise from vessels. It also has a precise sound signature since it usually operates at a fixed rotation frequency. If you think of it, an idling vehicle produces a tonal acoustic excitation. The sound energy distribution is mainly concentrated at a few precise frequencies and multiples. Indeed, the engine rotates at a given rotation speed – in round per minutes – or frequency (divided by 60, it is the number of oscillations per second). In addition to the rotating frequency, the firing order and the number of cylinders will lead to the generation of excitation multiples of the rotating frequency. The problem is that the produced frequencies are generally low and difficult to mitigate with classical soundproofing materials requiring substantial material thickness.
This research project delves into new solutions to mitigate underwater noise pollution using innovative noise control technologies. The solution investigated in this work is structured quarter-wavelength acoustic resonators. These resonators usually absorb sound at a resonant frequency and odd harmonics, making them ideal for targeting precise frequencies and their multiples. However, the length of these resources is dictated by the wavelength corresponding to the target frequency. As for the required material thickness, this wavelength is significant at low frequencies (in air, for a frequency of 100 Hz and a speed of sound of 340 m/s, the wavelength is 3.4 m since the wavelength is the ratio of speed by frequency). The length of a quarter wavelength resonator tuned at 100 Hz is thus 0.85 m.
Fig.1. Comparison between classical and innovative soundproofing material on sound absorption, from Centre de recherche acoustique-signal-humain, Université de Sherbrooke.
Therefore, a coiled quarter wavelength resonator was considered to reduce its bulkiness, and facilitate their installation. The inspiration follows Archimedes’ spiral geometry shape, a structure easily manufactured using today’s 3D printing technologies. Experimental laboratory tests were conducted to characterize the prototypes and determine their effectiveness in absorbing sound. We also created a numerical model that allows us to quickly answer optimization questions and study the efficiency of a hybrid solution: a rock wool panel with embedded coiled resonators. We aim to combine classic and innovative solutions tom propose low weight and compact solutions to efficiently reduce underwater noise pollution!
Fig.2. Numerical model of coiled resonators embedded in rockwool, from Centre de recherche acoustique-signal-humain, Université de Sherbrooke.
Quentin Brissaud – quentin@norsar.no
X (twitter): @QuentinBrissaud
Research Scientist, NORSAR, Kjeller, N/A, 2007, Norway
Sven Peter Näsholm, University of Oslo and NORSAR
Marouchka Froment, NORSAR
Antoine Turquet, NORSAR
Tina Kaschwich, NORSAR
Popular version of 1pPAb3 – Exploring a planet with infrasound: challenges in probing the subsurface and the atmosphere
Presented at the 186 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026837
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Low frequency sound, called infrasound, can help us better understand our atmosphere and explore distant planetary atmospheres and interiors.
Low-frequency sound waves below 20 Hz, known as infrasound, are inaudible to the human ear. They can be generated by a variety of natural phenomena, including volcanoes, ocean waves, and earthquakes. These waves travel over large distances and can be recorded by instruments such as microbarometers, which are sensitive to small pressure variations. This data can give unique insight into the source of the infrasound and the properties of the media it traveled through, whether solid, oceanic, or atmospheric. In the future, infrasound data might be key to build more robust weather prediction models and understand the evolution of our solar system.
Infrasound has been used on Earth to monitor stratospheric winds, to analyze the characteristics of man-made explosions, and even to detect earthquakes. But its potential extends beyond our home planet. Infrasound waves generated by meteor impacts on Mars have provided insight into the planet’s shallow seismic velocities, as well as near-surface winds and temperatures. On Venus, recent research considers that balloons floating in its atmosphere, and recording infrasound waves, could be one of the few alternatives to detect “venusquakes” and explore its interior, since surface pressures and temperatures are too extreme for conventional instruments.
Sonification of sound generated by the Flores Sea earthquake as recorded by a balloon flying at 19 km altitude.
Until recently, it has been challenging to map infrasound signals to various planetary phenomena, including ocean waves, atmospheric winds, and planetary interiors. However, our research team and collaborators have made significant strides in this field, developing tools to unlock the potential of infrasound-based planetary research. We retrieve the connections between source and media properties, and sound signatures through 3 different techniques: (1) training neural networks to learn the complex relationships between observed waveforms and source and media characteristics, (2) perform large-scale numerical simulations of seismic and sound waves from earthquakes and explosions, and (3) incorporate knowledge about source and seismic media from adjacent fields such as geodynamics and atmospheric chemistry to inform our modeling work. Our recent work highlights the potential of infrasound-based inversions to predict high-altitude winds from the sound of ocean waves with machine learning, to map an earthquake’s mechanism to its local sound signature, and to assess the detectability of venusquakes from high-altitude balloons.
To ensure the long-term success of infrasound research, dedicated Earth missions will be crucial to collect new data, support the development of efficient global modeling tools, and create rigorous inversion frameworks suited to various planetary environments. Nevertheless, Infrasound research shows that tuning into a planet’s whisper unlocks crucial insights into its state and evolution.
Applied Ocean Phusics and Engineering, Woods Hole Oceanographic Instuitution., Woods Hole, MA, 02543, United States
Andi Petculescu
University of Louisiana
Department of Physics
Lafayette, Louisiana, USA
Popular version of 3aPAa6 – Calculating the Acoustics Internal Gravity Wave Dispersion Relations in Venus’s Supercritical Lower Atmosphere
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0027303
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Venus is the second planet from the sun and is the closest in size and mass to Earth. Satellite images show large regions of tectonic deformations and volcanic material, indicating the area is seismically and volcanically active. Ideally, to study its subsurface and seismic and volcanic activity, we would deploy seismometers on the surface to measure the ground motions following venusquakes or volcanic eruptions; this will allow us to understand the planet’s past and current geological processes and evolution. However, the extreme conditions at the surface of Venus prevent us from doing that. With temperatures exceeding 400°C (854°F) and a pressure of more than 90 bars (90 times more than on Earth), instruments don’t last long.
One alternative to overcome this challenge is to study Venus’s subsurface and seismic activity using balloon-based acoustic sensors floating in the atmosphere to detect venusquakes from the air. But before doing that, we first need to assess its feasibility. This means we must better understand how seismic energy is transferred to acoustic energy in Venus’s atmosphere and how the acoustic waves propagate through it. In our research, we address the following questions. 1) How efficiently does seismic motion turn to atmospheric acoustic waves across Venus’ surface? 2) how do acoustic waves propagate in Venus’s atmosphere? and 3) what is the frequency range of acoustic waves in Venus’s atmosphere?
Venus’s extreme pressure and temperature correspond to supercritical fluid conditions in the atmosphere’s lowest few kilometers. Supercritical fluids combine gases and fluids’ properties and exhibit nonintuitive behavior, such as high density and compressibility. Therefore, to describe the behavior of such fluids, we need to use an equation of state (EoS) that captures these phenomena. Different EoSs are appropriate for different fluid conditions, but only a limited selection adequately describes supercritical fluids. One of these equations is the Peng-Robinson (PR) EoS. Incorporating the PR-EoS with the fluid dynamics equations allows us to study acoustics propagation in Venus’s atmosphere.
Our results show that the energy transported across Venus’s surface from seismic sources is two orders of magnitude larger than on Earth, pointing to a better seismic-to-acoustic transmission. This is mainly due to Venus’s denser atmosphere (~68 kg/m3) compared to Earth’s (~1 kg/m3). Using numerical simulations, we show that different seismic waves will be coupled to Venus’s atmosphere at different spatial positions. Therefore, when considering measurements from floating balloons, they will measure different seismic-to-acoustic signals depending on their position. In addition, we show that Venus’s atmosphere allows lower acoustic frequencies than Earth’s. This will be useful in 1) preparing the capabilities of the acoustic instruments used on the balloons, and 2) interpreting future observations.
Popular version of 2pAB8 – Moving Cargo, Keeping Whales: Investigating Solutions for Ocean Noise Pollution
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0027065
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Figure 1. Image Courtesy of ZoBell, Vanessa M., John A. Hildebrand, and Kaitlin E. Frasier. “Comparing pre-industrial and modern ocean noise levels in the Santa Barbara Channel.” Marine Pollution Bulletin 202 (2024): 116379.
Southern California waters are lit up with noise pollution (Figure 1). The Port of Los Angeles and the Port of Long Beach are the first and second busiest shipping ports in the western hemisphere, supporting transits from large container ships that radiated noise throughout the region. Underwater noise generated by these vessels dominate ocean soundscapes, negatively affecting marine organisms, like mammals, fish, and invertebrates, who rely on sound for daily life functions. In this project, we modeled what the ocean would sound like without human activity and compared it with what it sounds like in modern day. We found in this region, which encompasses the Channel Islands National Marine Sanctuary and feeding grounds of the endangered northeastern Pacific blue whale, modern ocean noise levels were up to 15 dB higher than pre-industrial levels. This would be like having a picnic in a meadow versus having a picnic on an airport tarmac.
Reducing ship noise in critical habitats has become an international priority for protecting marine organisms. A variety of noise reduction techniques have been discussed, with some already operationalized. To understand the effectiveness of these techniques, broad stakeholder engagement, robust funding, and advanced signal processing is required. We modeled a variety of noise reduction simulations and identified effective strategies to quiet whale habitats in the Santa Barbara Channel region. Simulating conservation scenarios will allow more techniques to be explored without having to be implemented, saving time, money, and resources in the pursuit of protecting the ocean.
Jian-yu Lu – jian-yu.lu@ieee.org
X (Twitter): @Jianyu_lu
Instagram: @jianyu.lu01
Department of Bioengineering, College of Engineering, The University of Toledo, Toledo, Ohio, 43606, United States
Popular version of 1pBAb4 – Reconstruction methods for super-resolution imaging with PSF modulation
Presented at the 186 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026777
–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–
Imaging is an important fundamental tool to advance science, engineering, and medicine, and is indispensable in our daily life. Here we have a few examples: Acoustical and optical microscopes have helped to advance biology. Ultrasound imaging, X-ray radiography, X-ray computerized tomography (X-ray CT), magnetic resonance imaging (MRI), gamma camera, single-photon emission computerized tomography (SPECT), and positron emission tomography (PET) have been routinely used for medical diagnoses. Electron and scanning tunneling microscopes have revealed structures in nanometer or atomic scale, where one nanometer is one billionth of a meter. And photography, including the cameras in cell phones, is in our everyday life.
Despite the importance of imaging, it was first recognized by Ernest Abbe in 1873 that there is a fundamental limit known as the diffraction limit for resolution in wave-based imaging systems due to the diffraction of waves. This effects acoustical, optical, and electromagnetic waves, and so on.
Recently (see Lu, IEEE TUFFC, January 2024), the researcher developed a general method to overcome such a long-standing diffraction limit. This method is not only applicable to wave-based imaging systems such as ultrasound, optical, electromagnetic, radar, and sonar; it is in principle also applicable to other linear shift-invariant (LSI) imaging systems such as X-ray radiography, X-ray CT, MRI, gamma camera, SPECT, and PET since it increases image resolution by introducing high spatial frequencies through modulating the point-spread function (PSF) of an LSI imaging system. The modulation can be induced remotely from outside of an object to be imaged, or can be small particles introduced into or on the surface of the object and manipulated remotely. The LSI system can be understood with a geometric distortion corrected optical camera in the photography, where the photo of a person will be the same or invariant in terms of the size and shape if the person only shifts his/her position in the direction that is perpendicular to the camera optical axis within the camera field of view.
Figure 1 below demonstrates the efficacy of the method using an acoustical wave. The method was used to image a passive object (in the first row) through a pulse-echo imaging or to image wave source distributions (in the second row) with a receiver. The best images obtainable under the Abbe’s diffraction limit are in the second column, and the super-resolution (better than the diffraction limit) images obtained with the new method are in the last column. The super-resolution images had a resolution that was close to 1/3 of the wavelength used from a distance with an f-number (focal distance divided by the diameter of the transducer) close to 2.
Because the method developed is based on the convolution theory of an LSI system and many practical imaging systems are LSI, the method opens an avenue for various new applications in science, engineering, and medicine. With a proper choice of a modulator and imaging system, nanoscale imaging with resolution similar to that of a scanning electron microscope (SEM) is possible even with visible or infrared light.
Fig.1. Comparison between classical and innovative soundproofing material on sound absorption, from Centre de recherche acoustique-signal-humain, Université de Sherbrooke.
Low frequency sound, called infrasound, can help us better understand our atmosphere and explore distant planetary atmospheres and interiors.
Venus surface. Image from NASA (
