EurOCEAN 2000 - Vlaams Instituut voor de Zee

approximately 2 hours at high water are analysed, a mean dimensionless run-up value of 1.80
is obtained. This value is higher than the values obtained in the small scale model tests up till
now. Actually (May 2000) further more detailed analysis of both prototype and scale model
Ru 2%
measurements is carried out. At mean tide increases to 2.25. This phenomenon has to
H
mo
Rd 2%
be checked in more detail as well. A run-down value ≅ 0.90 is deduced from the
H mo
prototype data. Fig. 5 shows the prototype results for 13 storms (during the period 1995 to
2000 with Hmo varying between 2.40 m and 3.10 m and T0,1 varying between 5.8 s and 6.6 s)
together with earlier small scale test results (Murphy et al. (1996) and Troch et al. (1996)). At
present (May 2000), laboratory tests are still going on.
For the Pettemer sea dike a reasonably good agreement between the prototype data analysis
results and the results from the laboratory experiments is found. A non-dimensional run-up of
about 2 is obtained (fig. 6).
Ru2%/Hmo - prototype
3,0
2,5
2,0
1,5
1,0
1,0 1,5 2,0 2,5 3,0
Ru2%/Hmo – model tests
Fig. 6: Comparison between wave run-up measured in prototype
and in model tests (van Gent (1999))
NUMERICAL MODELLING
Numerical models play a very important role in research and design of coastal structures.
Therefore it is of paramount importance that these models are as accurate as possible. The onedimensional
(e.g. ODIFLOCS, FLOx) numerical models are used as practical tools, whereas
the two-dimensional models (e.g. 2D-HYDROTUR, NASA-VOF2D, SKYLLA, VOFbreak²)
are regarded as research tools that require improvements in order to enhance their practical
value. In a first stage, an existing code is refined to treat arbitrary free surfaces and internal
obstacles by improving the numerical methods. Secondly new modules with a more thoroughly
calculation of particular physical phenomena are implemented.
Up till now, numerical models have only been calibrated against scale model test results. In
this project, these are calibrated with the results of the prototype measurements. The numerical
models are also considered as a complement to the laboratory and field measurements obtained
in the OPTICREST-project, to provide clues for interpreting eventual discrepancies, as well as
493