Technical Acoustics II

In the lecture an insight in various fields of applications related with acoustics is provided. Doing the exercises and homework the students learn to evaluate the applicability of these fields for practical problems. Based on the knowledge in structural dynamics the students shall become prepared for the work as a consulting engineer in technical acoustics. They shall be able to identify appropriate models and adequate solution techniques. They shall understand the limitations about the applied models and be able to abstract complex acoustical issues. This is explained at the basis of various examples.

The mechanisms for sound absorptions are explained starting with the plane wave approach leading to the description of porous media by means of the theory of porous media. The importance of the impedances of absorbers is illustrated. The basics of the in acoustics widely used Statistical Energy Analysis (SEA) are introduced and illustrated by examples. The advantages and disadvantages of the method are explained. Finally some special topics of Technical Acoustics are addressed, applying the basics learned in the previous part: Room acoustics, Railway induced vibrations and reradiated noise, Flow induced noise and the prediction of the effect of diffraction at barriers. For each of the problems common solution strategies and engineering approaches are explained and supported by calculation examples. Thematic outline: Statistical Energy Analysis (SEA) - Introduction in the averaging procedures in the SEA - Introduction in the treatment of coupled systems - Overview over the limitations of the method - Applications to examples like transmission loss of walls, sound field in rooms Room acoustics - Physical background: Description of rooms acoustics and properties - Impulse response - Spatial distribution of sound - Room acoustical parameters - Design of halls Railway induced vibrations and reradiated noise - Mechanisms - Measures for the abatement - Examples Flow induced noise - Lighthill analogy - Selected examples of practical relevance Propagation of sound in the open space: diffraction at barriers - Solutions at the basis of the partial differential equations - General phenomena