Page History

...

1. Analytical -  Wave penetration is computed on a grid within the harbour basin and is based on on the Cornu spiral waves propagating into the harbour basin principle (solving the Sommerfeld equations incl. Fresnel integrals). Note that this does not take into account processes such as reflection and diffraction.
2. Diffrac2DH - Wave penetration is computed using the numerical Diffrac2DH Diffrac2-DH schemisation (solving the Helmholtz equation). This method takes reflection and diffraction into account.

Literature

More information (literature) about the internal workings of the analytical and Diffrac-2DH calculations can be found here:

• Analytical
  • Goda, Y., Takayama, T. and Suzuki, Y., “Diffraction diagrams for directional random waves,” Proc. 16th International Conference Coastal Engineering. (Hamburg, 1978) pp. 628-650.
  • Carr, J.H. and Stelzriede, M.E. 'Diffraction of Water Waves by Breakwaters' (Section 2.2 in particular)
  • M.R., Boshek., "Reflection and Diffraction Around Breakwaters"
  • Wolfram MathWorld - Cornu Spiral
  • LibreTexts Physics - Phydics LibreTexts Cornu's Spiral
  • Key equations:
    • Fresnel integrals:
      Image Added
• Diffrac-2DH
  • Diffrac User-Manual (Appendix C in particular)
  • Key equations:
    • Helmholtz equation:
      Image Added
    • Horizontal boundary condition equation:
      Image Added
  Diffrac2DH
  • T

Tool limitations

The following processes are not included in the tool: wave directional spreading, bed level changes throughout the harbor, wave reflection (in case of using the analytical method) or varying reflection values (in case of Diffrac2DHDiffrac-2DH), etc.

More information on the limitations can be found through the provided literature.

Results of the wave penetration tool should therefore be interpreted with a considerable range of uncertainty.

...