#jsDisabledContent { display:none; } My Account |  Register |  Help

# Iribarren number

Article Id: WHEBN0039339697
Reproduction Date:

 Title: Iribarren number Author: World Heritage Encyclopedia Language: English Subject: Collection: Publisher: World Heritage Encyclopedia Publication Date:

### Iribarren number

Breaking wave types: free surface and bubble plumes, as redrawn from photographs taken during a wave flume experiment.[1]

In fluid dynamics, the Iribarren number or Iribarren parameter – also known as the surf similarity parameter and breaker parameter – is a dimensionless parameter used to model several effects of (breaking) surface gravity waves on beaches and coastal structures. The parameter is named after the Spanish engineer Ramón Iribarren Cavanillas (1900–1967),[2] who introduced it to describe the occurrence of wave breaking on sloping beaches.[3]

For instance, the Iribarren number is used to describe breaking wave types on beaches; or wave run-up on – and reflection by – beaches, breakwaters and dikes.[4][5][6]

## Contents

• Definition 1
• Breaker types 2
• References 3
• Footnotes 3.1
• Other 3.2

## Definition

The Iribarren number – often denoted as Ir or ξ – is defined as:[5]

\xi = \frac{\tan \alpha}{\sqrt{H/L_0}},   with   L_0 = \frac{g}{2\pi}\, T^2,

where ξ is the Iribarren number, α is the bed slope, H is the wave height, L0 is the deep-water wavelength, T is the period and g is the gravitational acceleration. Depending on the application, different definitions of H and T are used, for example: for periodic waves the wave height H0 at deep water or the breaking wave height Hb at the edge of the surf zone. Or, for random waves, the significant wave height Hs at a certain location.

## Breaker types

Breaker types.

The type of breaking wave – spilling, plunging, collapsing or surging – depends on the Iribarren number. According to Battjes (1974), for periodic waves propagating on a plane beach, two possible choices for the Iribarren number are:

\xi_0 = \frac{\tan \alpha}{\sqrt{H_0 / L_0}}   or   \xi_b = \frac{\tan \alpha}{\sqrt{H_b / L_0}},

where H0 is the offshore wave height in deep water, and Hb is the value of the wave height at the break point (where the waves start to break). Then the breaker types dependence on the Iribarren number (either ξ0 or ξb) is approximately:[4]

breaker type ξ0–range ξb–range
surging or collapsing ξ0 > 3.3 ξb > 2.0
plunging 0.5 < ξ0 < 3.3 0.4 < ξb < 2.0
spilling ξ0 < 0.5 ξb < 0.4

## References

### Footnotes

1. ^
2. ^
3. ^ Iribarren & Norales (1949)
4. ^ a b Battjes (1974)
5. ^ a b Holthuijsen (2007)
6. ^ Bruun (1984)

### Other

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.

Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.