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Hello,

I modeled an island with ARTEMIS to assess the wave climate in the area sheltered by a breakwater. It worked well...

But now I have to assess the incoming wave height along the breakwater, due to the refraction and shoaling. For this, I put a coefficient of reflection equal to 0 in order to avoid the interferences between the incoming and reflected waves. If I put Cr=0, is it possible that there are still some interferences?

The client asked to remove all the island in order to be sure that there are no interferences. I tried to remove it, but now the domain is totally empty and there are a lot of interferences between the liquid boundaries and the result is totally different than with the island in the model...

Do you have an idea?

With the first option (put Cr=0 for the breakwater) I get an increase of the wave height of 5%... I wonder about the confidence interval of ARTEMIS. Is 5% relevant?

Thanks a lot.

Gaëtan


PS: I use ARTEMIS because the model was already ready, and we didn't want to create a new model to assess the wave height along the breakwater...

Hi Gaetan,

1/
It is possible to have interferences even with a Cr=0, depending on the angle TETAP you specified. TETAP should be the angle of incidence of the waves on the segment considered. With a wrong TETAP, you can have interferences.

2/
You removed the island, OK. What are your boundary conditions in that case? Are the interferences significant? Quite often the interferences are due to a bad description of the TETAP angle on the boundary.

3/
If you don't find the solution, please send me your case for me to have a look.

Regards,

Christophe

Hi Christophe,

1/ Yes I tried to assess TETAP as much as possible, and the wave height increases up to 5% at the toe. But Ok, if I want to avoid the interferences I have to remove the island.

2/ The boundaries are liquid boundaries with incident or outcoming waves. And I tried to assess TETAP also as much as possible...

The directional spreading is equal to 30°, that is why it's difficult to estimate TETAP.


Thanks

Regards,

Gaëtan

Hi Gaetan,

If the directional spreading is 30°, then ARTEMIS will discretize the spectrum in several directions and solve the problem for each direction. You should change the value of TEPTAP depending on each direction.
In the BORH routine, you should write something as TETAP=FUNCTION(incident wave direction). Did you try that?