The aim of this benchmark is to better evaluate the capability of current sea-keeping codes to evaluates vertical bending moment, on extreme waves, on rigid hulls. Reference results are model tests performed at Ecole Centrale de Nantes (Experimental analysis of wave-induced vertical bending moment in steep regular waves)
Benchmark specification can be found below.
The model is a 6750 TEU container-ship, at scale 1:65. Geometry can be found in IGES format. (file input / 6750TEUcontainership-scale1_65-breakwater.igs). The hull geometry is the same as the one used in Benchmark study on motions and loads of a 6750-TEU containership, and mass properties are very close.
The geometry here provided corresponds exactly to the model (including protection from green-water for measurement equipment).
All coordinates are here given from aft perpendicular. Aft perpendicular is located 0.09045m forward from the transom.
| Units | Model | Full scale | |
|---|---|---|---|
| Lpp | m | 4.41 | 286.6 |
| Beam | m | 0.615 | 40 |
| Draft | m | 0.1843 | 11.98 |
| Mass | kg | 312.61 | 85849972 |
| X_CoG | m | 2.13 | 143.70 |
| Y_CoG | m | 0.0 | 0.0 |
| Z_CoG | m | 0.256 | 16.66 |
| R_xx | m | 0.18 | 12.0 |
| R_yy | m | 1.10 | 71.5 |
| R_zz | m | 1.10 | 71.4 |
| R_xz | m | -0.11 | -7.0 |
| Segment | Mass | X_CoG | Y_CoG | Z_CoG | I_xx | I_yy | I_zz | I_xz | X Segment connection |
|---|---|---|---|---|---|---|---|---|---|
| S1 | 31.749 | 0.365 | 0.0 | 0.265 | 0.866 | 1.805 | 1.819 | 0.082 | 0.62755 |
| S2 | 32.913 | 0.807 | 0.0 | 0.290 | 1.490 | 1.474 | 1.031 | -0.237 | 1.03755 |
| S3 | 25.975 | 1.242 | 0.0 | 0.185 | 0.719 | 0.722 | 0.871 | 0.001 | 1.44755 |
| S4 | 44.082 | 1.745 | 0.0 | 0.207 | 1.022 | 1.490 | 1.670 | -0.150 | 1.90455 |
| S5 | 40.669 | 2.054 | 0.0 | 0.214 | 1.025 | 1.481 | 1.658 | 0.021 | 2.36155 |
| S6 | 39.974 | 2.565 | 0.0 | 0.305 | 1.718 | 1.557 | 1.067 | -0.017 | 2.77155 |
| S7 | 34.666 | 3.002 | 0.0 | 0.305 | 1.413 | 1.367 | 1.019 | 0.166 | 3.18155 |
| S8 | 33.553 | 3.406 | 0.0 | 0.291 | 1.221 | 1.273 | 0.907 | 0.193 | 3.59155 |
| S9 | 29.027 | 3.919 | 0.0 | 0.242 | 0.567 | 1.959 | 1.999 | 0.039 |
The vessel is restrain with a soft mooring, which results in a surge natural period of 11.8s (95s full scale). This is considered far enough from the wave period not to impact significantly the wave loads.
k1 = k2 = k3 = k4 = 56 N/m
alpha = 45 degrees
Following waves are to be run by benchmark participants. All conditions are pure head waves, without any forward speed.
| ID | PERIOD (s) | HEIGHT (m) | LAMBDA (m) | Steepness (%) |
|---|---|---|---|---|
| Base case | (Lambda = Lpp) | |||
| 179 | 1.68 | 0.093 | 4.41 | 2.1% |
| 115 | 1.67 | 0.168 | 4.41 | 3.8% |
| 118 | 1.66 | 0.229 | 4.41 | 5.2% |
| 140 | 1.62 | 0.384 | 4.41 | 8.7% |
| 142 | 1.59 | 0.463 | 4.41 | 10.5% |
| Optional | (steepness = 5.2%) | |||
| 123 | 1.44 | 0.172 | 3.31 | 5.2% |
| 124 | 1.85 | 0.287 | 5.51 | 5.2% |
| 125 | 2.03 | 0.344 | 6.61 | 5.2% |
| 145 | 2.19 | 0.401 | 7.72 | 5.2% |
To ease the post-processing of the results, participants are kindly requested to respect the following guidelines.
-
Calculation information ( file to be named "participantId_info.dat" )
- Institution who is running the calculation
- Software category (among CFD, SPH, Fully non-linear potential, weakly non-linear potential)
- Software used
- Calculation time (order of magnitude).
-
Time series of Heave, Pitch and Vertical Bending Moment ( file to be named "participantID_caseID.dat" )
- 11 columns (time (s), heave (m), pitch (rad) and VBM_i (N.m), for all inter-segment from 1 to 8, separated with whitespace
- Results given at model scale
- Results should include still water loads
- First line will be interpreted as still water behavior (this first line could be added "manually" in case simulation would not start from rest)
- Time range considered as steady-state for each case should be specified in file "participantId_STABLE.dat"
Example of results are shown in folder "Example"
Results should be send by email.