Faculty of Engineering and Applied Science
INSTITUTE OF SOUND AND VIBRATION RESEARCH
MSc Sound and Vibration Studies Year: 2002-03




Module Specification



Unit/Module Code: Module Title:
IS651 Underwater Acoustics 2


1.Basic Information
 
Department responsible for the module ISVR
Programme MSc Sound and Vibration Studies  ; also available to MPhil/PhD students registered in ISVR
Timetable Semester 2
Session 2002-03
Credit Value 10 CAT points (= 100 hours) Level M
Pre-requisites Underwater Acoustics I
Co-requisites None
Module Lecturers Dr P R White (Co-Ordinator)
Contact prw@isvr.soton.ac.uk
Formal Contact Hours Lectures and tutorials (3 h/wk) = 24 hours
Private Study Hours Up to 50 hours own study time
Coursework None 
External Examiner Dr H Hunt 
Last Approved  
Last Revision 8/8/2002 
Course Web Site  
 
 
2.Description
 
2.1Aims
 
  The aims of this module are to:
  • To provide an overview of mathematical techniques used in sonar system modelling.

2.2Objectives (teaching)
 

 
  • To provide a summary of sonar system performance evaluation techniques, through the “sonar equations”.
  • To offer a basic understanding of the principles of simple acoustic propagation models.
  • To present the principles of array processing.
 
2.3Objectives (planned learning outcomes)
 
 Knowledge and understanding
Having successfully completed the module, you will be able to demonstrate knowledge and understanding of:
  • How to employ the sonar equations, to model and assess the performance of sonar systems.
  • The trade-offs involved when designing a sonar system.
  • Elementary modelling of acoustic scattering: as it affects both acoustic targets and volume reverberation.
  • The range of propagation models available.
  • Ray tracing methods in a range independent, deep water, context and in shallow water through the use of the method of images.
  • Normal mode methods for shallow water propagation modelling, assuming simple boundary conditions.
  • The motivation and use of arrays in sonar systems.
  • Basic array processing techniques, specifically array shading and electronic steering.
 
 Cognitive (thinking) skills
  Having successfully completed the module, you will be able to:
  • Read, understand and interpret the literature relating to underwater acoustics.
 
 Practical, subject-specific skills
Having sucessfully completed the module, you will be able to:
  • Undergo a paper design of a sonar system in an idealised scenario.
  • Advise on the selection of appropriate propagation models.
 
 Key transferable skills
Having successfully completed the module, you will be better able to:
  • Understand the issues associated with acoustic modelling in general.
  • Appreciate system design issues.



     
 
2.4Teaching and Learning Activities
 
 Teaching methods include
 
3 lectures a week. 
 
 Learning activities include
 
Working on examples provided to students in order to practise their analytical skills. Students are encouraged to read supporting texts and a booklist is provided. 
 
2.5Methods of Assessment (summative assessment)
 
 MSc Sound and Vibration Studies
      Assessment Methods Number % contribution to final mark Comment
      Written exam  1  100  2 h 

 
2.6Feedback to students during module study (formative assessment)
 
  • Previous examination papers with model answers are made available.
 
2.7Relationship between the teaching, learning and assessment methods
 
The examination tests students’ knowledge of the procedures, techniques and terminology of the material covered in the course. Students have a choice of questions in the exam (3 out of 5).
 
3.TOPICS COVERED
 

The Sonar Equations

  • Classes of sonar systems: Active/Passive, Monostatic/Bistatic.
  • Definitions of the basic terms within the sonar equations.
  • Signal detection criteria.
  • Derivation of the passive sonar equation
  • Derivation of the active (noise-limited) sonar equations.

Noise Level Calculations

  • Noise spectral level.
  • Bandwidth.
  • The effects of Doppler shifts.

Transmission Loss

  • Simple models for geometric losses.
  • Transmission loss due to absorption.





Target Strength Calculations

  • Geometric scattering from a sphere.
  • Rayleigh scattering from a sphere.
  • Resonant scattering from a sphere.

Volume Reverberation

  • The reverberation limit.
  • Calculation of volume reverberation level.
  • The transition between reverberation and noise limited operations.

Directivity Index Calculation

  • Directivity of a uniform line array at the design frequency.
  • Approximation for the directivity of a uniform line array at frequencies away from the design frequency.

Classes of Acoustic Propagation Models

  • Range dependent vs range independent.
  • 2-D and 3-D models.

Ray Tracing

  • The eikonal and transport equations
  • Snell’s law as obtained through the eikonal equation.
  • Travel times and distances travelled along rays.
  • Transmission loss along a ray.
  • Focusing factors, shadow zones and caustics.
  • Practical implementation of ray tracing models.

Method of Images

  • General expression for shallow water, isospeed propagation.
  • Specific solutions for various bottom conditions.

Method of Normal Modes

  • Model solution of the wave equation, in a sound channel.
  • Truncation of the modal series.
  • Phase and group velocities of modes.
  • Comparison with method of images solution.

Array Processing

  • Advantages of using an array.
  • General expression for the array gain of a uniform line array.
  • Electronic steering.
  • Array shading.




 
4.RESOURCES
 
 Core Texts
  AUTHORS TITLE/EDITION/DATE PUBLISHER UNI. LIB Class Mark E.J. Richards Library
1.None.

  Secondary Texts
  AUTHORS TITLE/EDITION/DATE PUBLISHER UNI. LIB Class Mark E.J. Richards Library
1. R J UrickPrinciples of Underwater Sound
3rd Edition, 1983
2nd Edition, 1975
1st Edition, 1967 (Appeared as: Principles of Underwater Sound for Engineers)		 McGraw Hill
007066087		QC 234.5 URI
1 loan
2 loan
1 loan
1 loan
2. I Tolstoy
C S Clay		Ocean Acoustics: Theory and Experiment in Underwater Sound
1st Edition, 1966
2nd Edition, 1987		 McGraw Hill

(No ISBN)
0070649413		QC 234.5 TOL

2 loan


1 loan
3. C S Clay
H Medwin		Acoustical Oceanography: Principles and Applications
1st Edition, 1977		 Wiley

0471160415		QC 234.5 CLA

1 loan
4. C S Clay
H Medwin		Fundamentals of Acoustical Oceanography
1st Edition, 1997		 Academic Press
012487570
5. L M Brekhovskikh
P Lysanov Yu.		Fundamentals of Ocean Acoustics
1st Edition, 1982
2nd Edition, 1991
 Springer Verlag
0387529764
3540113053		QC 234.5 BRE
1 loan
1 loan

1 loan
6. W S BurdicUnderwater Acoustic System Analysis
1st Edition, 1984
2nd Edition, 1991		 Prentice Hall


0139476075

1 loan
7. F G W CoatesUnderwater Acoustics Systems, 1990 Macmillan
0333425421		QC 234.5 COA
1 loan
8. L E Kinsler
A R Frey et al		Fundamentals of Acoustics
2nd Edition 1962
3rd Edition 1982		 Wiley

0471029335		QC 225 FUN
1 loan
5 loan
9 loan
2 loan
9. W Kuperman
F Jensen
H Schmidt
M Porter		Computerational Ocean Acoustics
2nd Edition, 2000		 American Institute of Physics
1563962098

 
 Other library support
 
The ISVR’s E J Richards Library houses a specialist collection relating to noise and vibration. 
 
 Staff required
 
1 lecturer. 
 
 Teaching space, layout and equipment required
 
A lecture room with 30 seats is required for three hours a week. The room should be equipped with overhead projection facilities, and blackboard and/or whiteboard. The occasional use of a data projector is required. 
 
 Laboratory space required
 
None. 
 
 Computer requirements
 
None. 
 
 Software requirements
 
None. 
 
 Off-campus activities
 
None. 
 
 Part-time/distance learning students
 
No special provision is made. 
 
 Other
 
A list of useful websites is provided.