Visar resultat 1 - 5 av 624 avhandlingar innehållade ordet Acoustics.
Sammanfattning : The search for quieter internal combustion engines drives the quest for a better understanding of the acoustic properties of engine duct components. Simulations are an important tool for enhanced understanding; they give insight into the flow-acoustic interaction in components where it is difficult to perform measurements. LÄS MER
Sammanfattning : The tonal character of the low frequency internal noise in cars is often due to energy transmission through the tyre at the first few eigenfrequencies of the air cavity of the tyre. The first acoustic mode in the air cavity of a typical stationary car tyre is approximately 224 Hz. LÄS MER
Sammanfattning : The search for quieter internal combustion engines drives the quest for a better understanding of the acoustic properties of engine duct components. In this work the main focus is the turbocharger compressor and a discussion of turbocharger acoustics and earlier work within the area is presented, giving an insight into its sound generating mechanisms and the damping effect it has on pressure pulses, i. LÄS MER
Sammanfattning : Shorter product development cycles, densely packed engine compartments and intensified noise legislation increase the need for accurate predictions of IC-engine air intake noise at early stages. The urgent focus on the increasing CO2 emissions and the efficiency of IC-engines, as well as new techniques such as homogeneous charge compression ignition (HCCI) might worsen the noise situation. LÄS MER
Sammanfattning : Transportation is a large and growing part of the world’s energy consumption. This drives a need for reduced weight of rail vehicles, just as it does for road vehicles. In spite of weight reductions, the vehicle still has to provide the same level of acoustic comfort for the passengers. LÄS MER