Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
On the relation between the wavefront speed and the group velocity concept
Swedish National Defence College, Department of Military Studies, Military-Technology Division.
1996 (English)In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 100, no 6, 3503-3507 p.Article in journal (Refereed) Published
Abstract [en]

The relation between the wavefront speed and the group velocity concept is studied in this work. The relationship between the more well-known velocity concept named as the phase velocity and the speed of propagation of a front of an acoustic pulse is discussed. This is of interest since it concerns transient wave propagation and is, in general, not well known. The form and properties of a pulse can be obtained by means of a Fourier integral and estimates based on quantities derived for monochromatic waves, such as the phase velocity, can be severely misleading and confusing. The wavefront velocity is defined as the high-frequency Limit of the phase velocity. This quantity can be far less than the value of the phase velocity for finite frequencies which for example is the case for bubbly fluids. Then the group velocity concept is discussed, which was introduced in order to characterize the propagation of water waves of essentially the same wavelength. However, more confusion occurs in that it is sometimes believed that a wavefront is propagating with the group velocity (a limit process not mentioned) since it can be related to the propagation of energy. This interpretation of energy propagation is based on sinusoidal waves and involves time as well as space averages and is not applicable for pulses. However, by means of the expression for the group velocity given by Stokes it is shown that the speed of a wavefront can be found from the group velocity at a limiting high frequency. This result can be understood geometrically from the definition of the group velocity given by Lamb which is conservation of wavelength. A wavefront is a discontinuity and limiting short wavelengths will be found there.

Place, publisher, year, edition, pages
1996. Vol. 100, no 6, 3503-3507 p.
National Category
Language Technology (Computational Linguistics)
Identifiers
URN: urn:nbn:se:fhs:diva-3960DOI: 10.1121/1.417249ISI: A1996VX67400002OAI: oai:DiVA.org:fhs-3960DiVA: diva2:627953
Available from: 2013-06-13 Created: 2013-06-11 Last updated: 2013-06-14Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Military-Technology Division
In the same journal
Journal of the Acoustical Society of America
Language Technology (Computational Linguistics)

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 35 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf