ISOPE 2020 IHC Comparative Study

Comparative Study on Steep Focused Waves Interactions with Fixed and Moving Cylinder

ISOPE-2020 Shanghai, China, June 14 – June 19, 2020

On behalf of ISOPE-2020 IHC, we invite you to join ‘Comparative Study on Steep Focused Waves Interactions with Fixed and Moving Cylinder’ organized by International Hydrodynamics Committee (IHC) of ISOPE.

The purpose of this comparative study is to share the state-of-the-art numerical analysis capability on the interactions between extreme waves and structure which is either fixed or with forward speed. In this comparative study, sets of experimental data, including the wavemaker motion and wave elevation, will be provided at prior. Participants should provide results of the time histories of the wave elevations and pressure data recorded at different positions.

Important Date

The deadline for the abstract: 20th Oct. 2019.

Numerical results deadline:  February 15, 2020

Circulation of the preliminary reportMarch 15, 2020

Final report: March 24, 2020

How to join the Comparative Study

 (a)  E-mail your participation form to vsriram@iitm.ac.in or shagun.1994@gmail.com if you’d like to submit a full paper to be included in the Conference Proceeding, please attach a one-page abstract when submitting the participation form.

(b)  Experimental data will be sent to participants no later than end of December

(c)  Email  your numerical results following a standard data format to  vsriram@iitm.ac.in or shagun.1994@gmail.com

 

We look forward to seeing you next year in Shanghai, China.

Sincerely yours,

Dr. V.Sriram, Session Organizer, Indian Institute of Technology Madras, Chennai, India

Dr. Shiqiang Yan, Session Co-organizer, City, University of London, UK.

Dr. Zhihua Xie, Session Co-organizer, Cardiff University, UK.

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Laboratory study on Steep wave interaction with fixed and moving cylinder

In this work a new set of experiments on the focused wave  generated using the 2nd order wavemaker theory interactions with cylinder is being carried out. Further, in order to represent a uniform current, laboratory experiments have been carried out in a wave flume, in which the cylinder is towed with a velocity opposite to the waves. The motion of the cylinder is controlled with the paddle generation using the inhouse developed data acquisition systems. The experiments were performed using the wave tank in Franzius-Institute at Leibniz University of Hannover, Germany. The tank is 110 m long, 2.2 m wide and 2m deep. Waves are generated by a computer-controlled hydraulically driven wave maker at one end of the tank. The tank was filled to a working depth (d) of 0.7 m with fresh water. The variation in water depth was found to be ≈ -2cm over a two days due to evaporation of the water. This was noted before every test since the slight variations may play a role in steep wave focusing.  Temporal variation of surface elevations at desired locations in the wave flume is recorded by seven capacitance wave gauges. The sampling rate for the wave gauges in these measurements is 100 Hz. A fixed wave gauge is present at 4.98m from the wave paddle, whereas, three wave gauges are mounted on the towing carriage. The cylinder with a diameter of 0.22 m is used with one wave gauge located 0.57m in the front of the cylinder center, the second wave gauge is located at x = 25 m in line with the center of the cylinder and the third wave gauge is located 0.71m behind the cylinder. The cylinder is hanged from the towing carriage along with three wave gauges as well as the EMS probe to measure the horizontal and vertical velocities in a 2D plane parallel to the flume wall 0.35m next to the cylinder center. Totally, eight pressure transducers are used, five pressure transducers are located at 00 with equal spacing in the front face, and the remaining three pressure transducers are located at 200, 900 and 1800. For some tests, the cylinder was rotated to obtain the pressure time history at different angles. The pressure transducers are recorded with high sampling frequency of 9600 Hz. In order to obtain good correlation with different runs, the repeatability of the experiments are confirmed by comparing the surface elevation measurements at the fixed wave gauge location (i.e. at 4.835m), the differences are within ±1% .  Different test cases with varying frequency bandwidth of the focusing waves, speed of the cylinder and the locations of focusing are investigated and will be reported in this paper.

The details about the wave generation scheme can be found at:

Sriram, V., Schlurmann, T., & Schimmels, S. (2015). Focused wave evolution using linear and second order wavemaker theory. Applied Ocean Research, 53, 279–296. https://doi.org/10.1016/j.apor.2015.09.007

The following figure is a schematic of the experimental setup. It represents the location of wave probes and pressure probes for which the data will be compared against the numerical models.

Schematic of the tank along with the wave probes and the cylinder

Schematic of the tank along with the wave probes and the cylinder

 

Schematic of the pressure probes mounted on the cylinder

Schematic of the pressure probes mounted on the cylinder

 

The following animations are from the experimental cases for moving cylinder interacting with breaking waves.

ISOPE-IHC-P2

ISOPE-IHC-P1-cut

 

 

The experimental data for the participants of ISOPE 2020 IHC “Comparative Study on Steep Focused Waves Interactions with Fixed and Moving Cylinder” will be released soon on this page. The participants will be notified about the updates.

Please download the participation form @ ISOPE 2020 form