Predicting Outdoor Sound

Keith Attenborough, Timothy Van Renterghem

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9780429894824
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Engineering General
• Index: Technology & Engineering

The second edition of Predicting Outdoor Sound is an up-to-date reference on the propagation of sound close to the ground and its prediction. New content includes comparisons between predictions and data for road traffic, railway and wind turbine noise; descriptions of source characteristics in the HARMONOISE model; propagation over rough seas, parallel low walls, and lattices; outlines of numerical methods; gabion (caged stones) and sonic crystal noise barriers; meteorological effects on noise barrier performance; and the prediction requirements for auralization.

The book brings together relevant theories, prediction schemes, and data, thereby providing a basis for determining what model or scheme might be applicable for any situation. It also offers a background on useful analytical approximations and the restrictions, as well as difficulties and limitations associated with engineering prediction schemes.

The text should be of considerable interest to researchers in outdoor sound propagation and, more generally, it should provide a comprehensive primer on the topic for lecturers, consultants and students in acoustics and noise control.

Chapter 1

Introduction

1.1Early Observations

The way in which sound travels outdoors has been of interest for several centuries. Initial experiments were concerned with the speed of sound [1]. In 1640, the Francisan (Minimite) friar, Marin Mersenne (1588–1648), timed the interval between seeing the flash and hearing the report from guns fired at a known distance and obtained a value of 450 m/s. In 1738, the French Academy of Science used the same idea with cannon fire and reported a speed of 332 m/s which is remarkably close to the currently accepted value for standard conditions of temperature (20°C) and pressure (at sea level) of 343 m/s. William Derham (1657–1735), the rector of a small church near London, was first to observe the influence of wind and temperature on sound speed and remarked on the difference between the sound of the church bells at a certain location over newly fallen snow compared with their sound at the same location without snow but with a frozen ground surface.

Many records of the strange effects of the atmosphere on the propagation of sound waves have been associated with war [2, 3]. In June 1666, Samuel Pepys wrote that the sounds of a naval engagement between the British and Dutch fleets were heard clearly at some spots but not at others a similar distance away or closer. Pepys spoke to the captain of a yacht that had been positioned between the battle and the English coast. The captain said that he had seen the fleets and run from them, ‘…but from that hour to this hath not heard one gun…’. The effects of the atmosphere on battle sounds were not studied in a scientific way until after the First World War (1914–1918). During that war, acoustic shadow zones, similar to those observed by Pepys, were observed during the battle of Antwerp. Observers also noted that battle sounds from France only reached England during the summer months and were best heard in Germany during the winter. After the war there was great interest in these observations among the scientific community. Large amounts of ammunition were detonated throughout England and the public was asked to listen for sounds of explosions.

Although there was considerable interest in atmospheric acoustics after the First World War, the advent of the su...