[Jie Hong]

Hi Team REEF3D,

I would like to use REEF3D to simulate the breaking wave. I find that REEF3D has an advantage in the simulation of breaking waves.

I have carried out an experiment of breaking waves in a wave flume with wave-focusing technology. To simulate the same case as the experiment, I prefer to carry out the numerical simulation with a piston wavemaker since the wavemaker kinematics are known.

Based on the example of Rectangular Wave Tank with Wavemaker in the Tutorial, I have added a turbulence model of k-ω turbulence model. The factor for eddy viscosity limiter is referred to the example of Plunging Breaking Waves over Slope. However, the calculation would be terminated with the error of “EMERGENCY STOP -- velocities exceeding critical value N 61”.
If I just decrease the factor for eddy viscosity limiter in phase 2, the calculation would be completed. It can be seen that the wave becomes steep but there are no breaking waves in the result.

I am wondering the details of the factor for eddy viscosity limiter and what the phase 1 and 2 represent. I am also wondering the meaning of FSF boundary mentioned in the function T 36.

I would like to ask for some help in how to improve the numerical model to make wave breaks. The control and ctrl files are attached if needed. Thanks in advance if you can help with this.

Kind regards
Jie Hong

[kamath]

I don't see anything wrong with your input with respect to the T commands.
If you would like, following Kamath et al. (2019), Water 11(3), 456, you can use T 37 = 0.07 * local water depth in combination with T 36 2.

The reason for your crash is more likely to be from the input conditions. Since you use the piston wavemaker input, I cannot investigate further without that input.

Also, the lack of a breaking waves is most probably related to grid resolution. Again, this is hard to comment upon in the absence of information related to the incident wave conditions and the scale of the overturning wave crest.

Hope that helps

[valgrinda]

In the absence of a bottom slope, this looks like a focused breaking wave. From experience, these type of breaking waves are often more spilling than plunging. That would mean smaller length scales and corresponding a finer grid requirement.

[Jie Hong]

Dear Mr. Kamath and Mr. Bihs:

Thanks for your reply. I have been trying to refine the grid resolution to make wave break. As I reduced the grid size to 0.01, the calculation would continue to the end without any error messages. A better simulation result is achieved than before. But the generated waves still do not break. Several snapshots are attached to show you the water free surface. It looks like it is going to break.

I am sorry for the missing wavemaker.dat. The modified control files and corresponding wavemaker data are attached below. Since the filetype of dat is not supported in the forum, the wavemaker.dat has been converted to a txt file.
In the experiment of the same case, the breaking wave height is near 0.26 m with a water depth of 0.8 m. The breaking wave type is plunging.

I wonder if I should keep on refining the grid. Thanks in advance.

Kind regards
Jie Hong