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CODE 60338
ACADEMIC YEAR 2023/2024
CREDITS
SCIENTIFIC DISCIPLINARY SECTOR ING-INF/03
LANGUAGE Italian
TEACHING LOCATION
  • GENOVA
SEMESTER 2° Semester
TEACHING MATERIALS AULAWEB

OVERVIEW

The objective of this module is to provide students with an understanding of the basic principles of radar, sonar, magnetic and infrared measurement systems, and how they interact with ships, especially in relation to the acoustic emission and electromagnetic response.

AIMS AND CONTENT

LEARNING OUTCOMES

Building on the concepts of wave, elastic or electromagnetic fields, the module addresses the characterization and evaluation of the specific signature produced by a ship, in its acoustic, electromagnetic, and infrared components, in relation to the possibility of detecting the ship itself with sonar, radar, thermal imaging cameras, and magnetometers.

AIMS AND LEARNING OUTCOMES

The module aims to provide students with a general understanding of the concepts of underwater noise, infrared emission, radar response and magnetic signature of a ship and the mechanisms that govern them. Upon completion of the module, the student will be able to:

  • describe the basic principles of ship acoustic and electromagnetic signatures;
  • understand the impact assessments of said signatures, especially in relation to the probability of detection of the ship;
  • analyze operation and purpose of radar and sonar systems;
  • solve simple design problems related to the signatures mentioned above.

PREREQUISITES

No additional knowledge and skills are required beyond those of students admitted to the Master of Science in Naval Engineering.

TEACHING METHODS

Classroom lectures and of case studies' description, often with the support of slides provided to students in advance, as well as visits to department laboratories and seminars by industrial experts. Attendance at all these activities is recommended.

SYLLABUS/CONTENT

ACOUSTIC SIGNATURE

  • Introduction: underwater acoustic noise, conversion efficiency: vibration, transmission, radiation.
  • Spectrum of a signal: Fourier transform; periodic signals and Fourier series; random signals; stationarity; autocorrelation and power spectral density.
  • Acoustic waves in fluids: nature of waves, wave equation, plane waves and spherical waves, acoustic impedance, intensity and power, decibel measurements.
  • Propagation losses: geometric spreading, medium absorption, transmission loss for spherical waves, sound velocity profile, acoustic ray tracing, ray trajectory curvature.
  • Passive sonar equation: quantities involved, signal-to-noise ratio, expected performance, ambient acoustic noise, relation with ship acoustic signature.
  • Radiated noise: monopole, dipole, quadripole; efficiency, directivity, examples; propeller tonal radiation and singing.
  • Cavitation: general aspects and types; propeller cavitation; calculation models; surface and submersible vessels.
  • Flexural vibration: mechanical noise generation; vibration transmission; vibration radiation.
  • Flow noise: origin, radiation, interactions.
  • Summary of noise sources: relative importance; effect of velocity; radiated acoustic power; calculation of radiated noise level.
  •  

ELECTROMAGNETIC SIGNATURES

  • Introduction and basic concepts of electromagnetic fields: field vectors and sources, Maxwell's equations.
  • Electromagnetic fields in materials: constitutive equations and dispersion.
  • Electromagnetic waves: propagation and radiation.
  • Fundamental concepts of antennas and main types of antennas used in shipbuilding.
  • Radar: principles of operation and resolution.
  • Radar equation and range calculation.
  • Radar cross section and radar signatures in the naval field.
  • Electromagnetic emission: blackbody radiation, elements of Planck's laws, Stefan-Boltzmann, Wien.
  • IR imaging and infrared signatures in the naval domain.
  • Magnetic signatures: main sources of signatures (ferromagnetic materials and magnetization, eddy currents, mention of corrosion effects), models for prediction.
     

RECOMMENDED READING/BIBLIOGRAPHY

D. ROSS, Mechanics of Underwater Noise, Peninsula Publishing, 1987

R. J. URICK, Principles of Underwater Sound, 3rd edition, McGraw-Hill, 1983

X. LURTON, An Introduction to Underwater Acoustics, Principles and Applications, Second Edition, Springer-Praxis, 2010.

M. SKOLNIK, Introduction to radar systems, 3rd ed., McGraw-Hill, 2001.

 

TEACHERS AND EXAM BOARD

Exam Board

ANDREA TRUCCO (President)

ANDREA RANDAZZO

ALESSANDRO FEDELI (President Substitute)

LESSONS

Class schedule

L'orario di tutti gli insegnamenti è consultabile all'indirizzo EasyAcademy.

EXAMS

EXAM DESCRIPTION

Oral test on the topics covered in the classroom lectures, laboratory and any industrial seminars. Students with specific learning disorders will be allowed to adopt specific modalities and supports that will be determined on a case-by-case basis, in agreement with the Engineering Course Delegate in the Commission for the Inclusion of Students with Disabilities.

 

ASSESSMENT METHODS

The oral test will assess the ability to describe the principles governing acoustic and electromagnetic wave fields, the different signatures of the ship, and the operation of radar and sonar systems, discussing the relative importance of the various sources in relation to the ship. It will also assess the technical language and the ability to analyze simple practical problems, reasoning with autonomy and rigour.
 

Exam schedule

Data Ora Luogo Degree type Note
09/01/2024 09:00 GENOVA Esame su appuntamento Aula D3
09/01/2024 09:00 GENOVA Orale Aula D3
23/01/2024 09:00 GENOVA Esame su appuntamento Aula D3
23/01/2024 09:00 GENOVA Orale Aula D3
13/02/2024 09:00 GENOVA Orale Aula D3
13/02/2024 09:00 GENOVA Esame su appuntamento Aula D3
04/06/2024 09:00 GENOVA Orale Aula D3
04/06/2024 09:00 GENOVA Esame su appuntamento Aula D3
19/06/2024 09:00 GENOVA Esame su appuntamento Aula D3
19/06/2024 09:00 GENOVA Orale Aula D3
09/07/2024 09:00 GENOVA Orale Aula D3
09/07/2024 09:00 GENOVA Esame su appuntamento Aula D3
03/09/2024 09:00 GENOVA Esame su appuntamento Aula D3
03/09/2024 09:00 GENOVA Orale Aula D3

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