Review of splitter silencer modeling techniques

QC 20220607</p

Review of splitter silencer modeling techniques

QC 20220607</p

Production cost development for commercial exhaust systems

Muffling devices are essential parts of any vehicle/machine that uses internal combustion engines. From automotive manufacturers point of view, they contribute massive sheet metal processing and production time, especially mufflers that are produced at high rates for commercial vehicles. This paper is concerned with applying manufacturing procedures to reduce the production cost of any commercial automotive mufflers through theoretical studies and experimental measurements verification. Mufflers design parameters such as transmission loss, flow generated noise and pressure drop were selected for performance judgment, parameters were simulated and experimentally measured. The transfer matrix method was used to calculate the propagation of sound waves along the muffler. A commercial automotive muffler with a hybrid combination of dissipation and reflection was selected for application and a new design was proposed for this muffler with a reduced manufacturing cost. The manufacturing processes were reduced by 77.7% and consequently the cost relative to the original muffler. Keywords: Commercial vehicle, Vehicle economics, Perforated muffler, Dissipative muffler, Exhaust system manufacturin

Multiphysics Modelling and Simulation for Systems Design Conference

This book reports on the state of the art in the field of multiphysics systems. It consists of accurately reviewed contributions to the MMSSD’2014 conference, which was held from December 17 to 19, 2004 in Hammamet, Tunisia. The different chapters, covering new theories, methods and a number of case studies, provide readers with an up-to-date picture of multiphysics modeling and simulation. They highlight the role played by high-performance computing and newly available software in promoting the study of multiphysics coupling effects, and show how these technologies can be practically implemented to bring about significant improvements in the field of design, control and monitoring of machines.  In addition to providing a detailed description of the methods and their applications, the book also identifies new research issues, challenges and opportunities, thus providing researchers and practitioners with both technical information to support their daily work and a new source of inspiration for their future research

Discovery of a big void in Khufu’s Pyramid by observation of cosmic-ray muons

International audienceThe Great Pyramid or Khufu’s Pyramid was built on the Giza Plateau (Egypt) during the IVth dynasty by the pharaoh Khufu (Cheops), who reigned from 2509 to 2483 BC$^1$ . Despite being one of the oldest and largest monuments on Earth, there is no consensus about how it was built. To better understand its internal structure, we imaged the pyramid using muons, which are by-products of cosmic rays that are only partially absorbed by stone. The resulting cosmic-ray muon radiography allows us to visualize the known and potentially unknown voids in the pyramid in a non-invasive way. Here we report the discovery of a large void (with a cross section similar to the Grand Gallery and a length of 30m minimum) above the Grand Gallery, which constitutes the first major inner structure found in the Great Pyramid since the 19$^{th}$ century. This void, named ScanPyramids Big Void, was first observed with nuclear emulsion films installed in the Queen’s chamber (Nagoya University), then confirmed with scintillator hodoscopes set up in the same chamber (KEK) and re-confirmed with gas detectors12 outside of the pyramid (CEA)This large void has therefore been detected with a high confidence by three different muon detection technologies andthree independent analyses. These results constitute a breakthrough for the understanding of Khufu’s Pyramid and its internal structure. While there is currently no information about the role of this void, these findings show how modern particle physics can shed new light on the world’s archaeological heritag