Ansys Acoustics’ Post

ACROSS ACOUSTICS Listen to the first part of the latest round of POMA Student Paper Competition winners talk about their research in ship noise, underwater micronavigation, and rotorcraft noise. https://lnkd.in/gXeyisBK (Soundbite transcript: "So when you have a helicopter rotor, the broadband noise frequencies are several 1000 Hertz, because these are the high frequencies of turbulence. But the blade passage frequency is going to be a lot less, on the order of, let's say, tens of Hertz, and that's really what you're hearing when you hear a helicopter chop or buzz. Your brain can't make out 5000 cycles per second, but it really locks onto the 10 cycles per second. So time-varying broadband noise is important for human perception of sound. But that being said, most aircraft noise research doesn't typically consider the time variation of broadband noise, so that's what my research wants to address.") CRASH-UdeS Penn State College of Engineering

This week, the 15th Aachen Acoustics Colloquium, organized by FEV, HEAD acoustics GmbH, Institute for Hearing Technology and Acoustics (IHTA), RWTH Aachen University and fka GmbH took place at the Parkhotel Quellenhof Aachen. Around 190 participants used the opportunity to learn more about the latest developments in the field of vehicle acoustics in 20 presentations. This year's focus was on vibroacoustic phenomena in the various vehicle components and on digital technology in the vibroacoustic development process.   Our colleague Michael Häußler presented the latest findings for low-noise charging in the mega-watt range for electric trucks. This is required in order to make the best possible use of the drivers' rest periods to top up the energy stores. Reducing the resulting noise was identified as an important factor in increasing acceptance among both users and the general public. As part of its study, the FEV team of experts identified the most significant sources of noise during the charging process and developed targeted measures for cooling systems. #feelevolution and visit www.fev.com for further information!

According to the Oxford English Dictionary, Acoustics is the branch of physics concerned with the properties of sound, and aeroacoustics is a subcategory. However, while aeroacoustics definitely falls under that umbrella, it also encompasses aerodynamics, which contributes to the conditions that cause the sound; and therefore, it gets a little complicated. If you want to know more, click on the link, and don't forget to follow @GRAS Sound and Vibration, our affiliated page dedicated to the automotive industry. Read more: https://lnkd.in/exMZQmBX

This paper proposes an arrangement that partitions the channel training stage into several phases, where the #reconfigurable #intelligent #surfaces (#RISs) reflection coefficients are pre-designed and the effective superposed channel is estimated instead of separately training the source-destination and source-RIS-destination links. Based on this, the active beamformer can be designed at low complexity and the RIS reflection optimization is performed by selecting that one from the pre-designed training set which maximizes the achievable rate. Secondly, the authors propose novel techniques for generating the training set of RIS reflection coefficients. The theoretical performance of the proposed scheme is analyzed and compared to the optimal RIS configuration. ----Jiancheng An, Lajos Hanzo More details can be found at this link: https://lnkd.in/gUZGUFdy

I’m happy to share that the project I’ve been working on, together with Emma San Martin and Professor George N. Barakos, has been published in Vol. 157 of the Journal of Aerospace Science and Technology. The research provides valuable insights and a deeper understanding of the aerodynamic and acoustic interactions, including synchrophasing effects, in multirotor systems, like those on the Boeing CH-47 Chinook helicopter or advanced aerial mobilities (AAM).

🚀 Excited to share that my latest research has been published in the Journal of Fluids and Structures! Check out the article here: [https://lnkd.in/dSunvbau] In this study, we delved into the intricacies of aerodynamics by conducting numerical simulations of the flapping motion of a rectangular wing in a three-dimensional flow field, utilizing the discrete vortex method (DVM). The beauty of DVM lies in its computational efficiency, eliminating the need for grid generation at each time step, unlike conventional methods. But here's where it gets exciting - we didn't just stop at the rigid wing case. We explored the dynamic world of deformable wings, investigating various configurations like bending, twisting, and the intriguing bending-twisting coupling (BTC). Our novel aerodynamic technique in wing twisting, revolving around a dynamically adjusted point at the root of the leading edge, proved remarkably effective in enhancing aerodynamic force. A huge shoutout to my supervisors Devranjan Samanta and Dr. Srikant Sekhar Padhee Sir for their invaluable guidance throughout this journey. Together, we're pushing the boundaries of aerodynamics, one flap at a time! 🌟 #Aerodynamics #Research #Innovation #FlappingWings

Its out ! Our last paper on the aerodynamics of flapping wings has been published in Physics of Fluids: https://lnkd.in/eGMwfPDy Brilliant work by Romain Poletti and Andre Calado at the von Karman Institute for Fluid Dynamics, with invaluable support from Lilla Kapa and Joris Degroote from Ghent University. 🔍 This work dives deep into the unsteady aerodynamics of flapping wings in hovering flight, exploring the complex interactions of leading-edge vortices (LEV), rotational circulation, and wing-wake interactions. We employed an advanced combination of CFD tools (LES, Overset methods, potential flow simulations) and post-processing techniques (Extended POD, finite-time Lyapunov exponent) to unravel the mechanisms of lift generation in both “smooth” and “aggressive” flapping. #CFD, #Aerodynamics, #FlappingWings, #PhysicsOfFluids, #UnsteadyAerodynamics, #Research

As part of the research on the high-altitude long-endurance plus 3D position control platform, which is being advanced under the "Mothership Project," the study "Angle Estimation Using Infrared Camera in Outdoor Environment" by X. Deng from Toyota's U.S. research base TRINA and T. Tsukada from the Toyota Frontier Research Center has been published in IEEE Access. This paper introduces a method for estimating the attitude angles of an aerial vehicle in an outdoor environment using onboard camera footage. https://lnkd.in/gx8Ahf4m https://lnkd.in/gQgwYVi4

My coauthors, Stanislav Gordeyev, Matthew Kemnetz, and Mark Spencer, and I are happy to announce that we recently published a two-part tutorial on aero-optical effects in Optica’s Journal of the Optical Society of America A (JOSA A). Aero-optical effects refers to laser beam disturbances caused by the environment in proximity of an aircraft. In part I, we provide introductory material with an emphasis on system-level considerations, particularly for those who are new to the field of aero-optics. In part II, we move on to survey several sources of aberrations. For example, we cover foundational sources like boundary layers and shear layers, as well as miscellaneous sources like mechanical contamination, shock waves, and aero acoustics. This two-part tutorial also differs from previous efforts in that it (1) includes very detailed explanations on both the aerodynamic and optical effects, specifically for new researchers trying to investigate this field; (2) discusses recent results related to aero-optical effects at supersonic and hypersonic speeds, in addition to subsonic speeds; and (3) introduces the aero-optical effects associated with shock waves, mechanical contamination, and aero-acoustics, which all lead to aberrations that degrade performance at the system level. As such, (1)–(3) will inform future efforts looking to implement laser systems on airborne platforms. For those interested in reading part I and II of this tutorial, they are openly available online and can be found through the following links: https://lnkd.in/gHT6zxMu https://lnkd.in/grhbepP4

Tomorrow, we'll be happy to introduce a new Axial Fan Acoustic Benchmark. In this project, we deal with the engineering simulation of Computational Aero-Acoustics (CAA), focusing on the Axial Fans. Employing advanced techniques like resolved CFD simulation together with the Acoustic Analogy and Ffowcs Williams-Hawkings, we explore the transient simulation with Finite Volume CFD simulations in a cell-centered framework. The mesh generation utilizes SnappyHexMesh with inflation layers powered by OpenFOAM and within the TCAE environment. Our study employs the k ω SST-DES model. We assess the Sound Pressure Level (SPL), Power Spectral Density (PSD), present Polar plots, and backward sound reconstruction. This comprehensive analysis sheds light on the fascinating world of CAA and its applications in aerodynamics.