Benchmark Experimental Data: Water-Wave Interactions with a Flexible Beam

Experimental Data for the Experimental Modeling of Water-Wave Interactions with a Flexible Beam

This submission is based on the GitHub repository which was created to share the experimental data presented at the 42nd International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2023) in Melbourne, Australia in the form of a conference paper 'Experimental Modeling of Water-Wave Interactions with a Flexible Beam'[1]. The paper has already been published and is available but only behind a paywall. A talk has also been delivered at OMAE 2023. The paper presents a series of fluid-structure-interaction (FSI) experiments for studying water-wave interactions with a flexible beam in a wide range of sea conditions thus yielding a variety of FSI test-case data. The experimental campaign is carried out at the Maritime Research Institute Netherlands's (MARIN's) concept basin. The concept basin is a 220m-long, 4m-wide and 3.6m-deep rectilinear basin with a carriage that can transverse along the basin's length. 

The experimental setup includes a flexible beam which is fixed to the basin's carriage at one end while the other free end is submerged in the water. The setup is designed such that it admits the simultaneous measurements of incident waves and the beam's response. Hence, it is suitable for studying FSI problems. The details about the dimensions of the beam and arrangements of the sensors are described in the form of detailed CAD drawings which are given in CAD_fsi_beam_exp.pdf. The shared CAD drawings could be used in the future to reproduce the model. 

The aim is to use these experimental data to validate FSI solvers commonly employed by the maritime industry in the design of fixed-foundation, offshore wind turbines. The study is divided into three experimental cases which are as follows (click on the case number to read more description):

Case-1 experiments: regular-water-waves interactions with the flexible beam when the carriage is at rest

Case-2 experiments: regular-water-waves interactions with the flexible beam when the carriage is moving at a constant speed

Case-3 experiments: irregular-water-waves interactions with the flexible beam when the carriage is at rest

FSI Experiments: Interactions of water-wave with a flexible beam

"All measurements are given in the form of .h5 format files, each of which has a corresponding .pan format file containing details of measurement names, units, frequency, maximum, minimum and standard deviation. The data presented is classified into different folders given as follows:"

Folder Exp1_carriage_rest_0.25m;

Folder Exp1_carriage_rest_0.5m;

Folder Exp2_carriage_moving_0.25m;

Folder Exp2_carriage_moving_0.5m;

Folder Exp3_irreg_waves_0.25m;

Folder Exp3_irreg_waves_0.5m; and

Folder hammer_test.

The description of the measurement and corresponding wave parameters are given in each folder.

Data organisation

All the main folders have several sub-folders and each sub-folder consists of mainly two types of files, i.e. .pan and .h5m. The files with extension .pan state the general information about experimental tests and sensors in text format. These .pan have three rows and the third row is divided into several columns. The second row states the information related to the experimental test, for example, the test number (80372_XXCB_XX_XXX_XXX_XX), project name (AEGRE), submerged depth of the beam (Proeven XX), gain, facility name (CB stands for concept basin), and scale (1.000). The first column of the third row shows the abbreviated sensor names which are explained in the table below.

TABLE 1: The names and descriptions of the sensors are listed.

Name
Description

C.SPEED
Speed of the carriage

WAVE.FORE
Wave elevation measured by the probe located at the front of the beam (26.25 m away from the wavemaker)

WAVE.SB
Wave elevation measured by the probe located parallel to the beam (30 m away from the wavemaker)

AX_i
Accelerations of the beam in x-direction recorded by the accelerometer, where i denotes the accelerometer number

AY_i
Accelerations of the beam in y-direction recorded by accelerometer, where i denotes the accelerometer number

AZ_i
Accelerations of the beam in z-direction recorded by accelerometer, where i denotes the accelerometer number

Flap 3 Pos
Position of the waveflap wavemaker

The number with the accelerations, e.g. AX.1, AY.2, and AZ.3, denotes the position of the accelerometer along the beam. The response of the beam is dominant in the direction of wave, i.e. x-direction, therefore the .h5m files contain accelerations in the x-direction for all of the accelerometers. The accelerometers are numbered from 1 to 6, where accelerometer number 1 is at the submerged free end of the beam while accelerometer number 6 is located at the fixed end of the beam. The rest of the accelerometers are numbered 2 to 5 from the free end to the fixed end. The files with extension .h5m contain the actual time-domain measurements obtained from the sensors. Each .h5m from the experimental case contains acceleration signal from all six accelerometers in the x-direction, wave elevation measured by the probe that is 26.25 m away from the wavemaker, wave elevation measured by the probe that is 30 m away from the wavemaker, carriage speed, and variation waveflap position throughout the run. These measurements can be read with the help of post-processing code. The post-processing codes based on MATLAB and Python scripts, with comments, are shared. The names of the MATLAB and Python scripts are read_model_tst.m and read_model_tst.py respectively. Each script needs the name of the .h5m file as user input. In addition to reading the .h5m file, the script plots the signals from the sensors. For demonstration, the provided MATLAB script is used to plot the comparison of the wavemaker position with the wave elevation measured by the wave probe that is 26.25 m away from the wavemaker.

References

[1] Rehman, W., Bunnik, T., Bokhove, O. and Kelmanson, M. “Experimental Modeling of Water-Wave Interactions with a Flexible Beam.” Proc. ASME 2023 42nd Int. Conf. on Ocean, Offshore and Arctic Eng.: p. 10. 2023. ASME.