Researchers Measure Breakwater Wave Dissipation Using Mikrotron High-Speed Cameras

Summary

July 18, 2022 - Floating breakwaters are lightweight, low cost pontoon-type structures used to minimize coastal erosion, intercept the movement of sediments, and help isolate vessels from marine hazards by dissipating wave energy. Floating breakwaters are increasingly seen as an alternative to fixed concrete breakwaters that are both expensive and time-consuming to construct. Concrete breakwaters also require a high-resistance seabed, unlike a floating breakwater that only needs a substrate for mooring lines.
 
Researchers at the Islamic Azad University in Tehran, Iran conducted an extensive review of floating breakwater performance, executing a series of tests on two different cubic shapes—a simple pontoon and a stepped slope pontoon—featuring unique transfer coefficients. Each was subjected to various sea conditions, with the performance evaluated and calculated. Finally, after analyzing and comparing the obtained transmission coefficients, the best breakwater in terms of performance in the developed laboratory conditions was determined by the researchers.
 
In each experiment, the two floating breakwaters were subjected against 250 regular and irregular waves, events that were captured with a Mikrotron MotionBlitz Cube high-speed camera at 100 frames-per-second (fps). MATLAB and AutoCAD software processed the resulting images. Each test on the different floating breakwaters ran 44 seconds using a hinged wave maker able to produce different wave heights, wave lengths, time periods and speeds within the lab's wave channel. Individual frames from the video were analyzed to determine the wave's transmission through the breakwater, specifically its height before and after impact.
 
Since its resolution and speed can be variably adjusted, the Mikrotron MotionBLITZ EoSens camera proved to be extremely flexible and thus met the researcher's requirements for test purposes. Owing to the built-in circular buffer, the camera can record experimental set-ups up to 13 seconds at full resolution without any connection to a notebook or PC. Frame rates up to 523 frames per second ensure consistent control of fast processes, even in poor and changing lighting conditions.
 
After analyzing and comparing the obtained transmission coefficients, the best breakwater design in the developed conditions was determined. Based on test data analysis, in shorter duration waves and lower drafts, simple pontoons were adequate protection, while in longer duration wave periods and deeper drafts, a stepped pontoon breakwater was required.

About Mikrotron GmbH

Mikrotron GmbH, established in 1976 and located just outside Munich, Germany, provides a full range of high-end imaging solutions for challenging applications in industry, engineering, science and sports. The company designs, produces, and commercializes high-speed and high-resolution cameras, image recording cameras and systems, software and image processing components. Mikrotron's slow-motion recording enables customers to optimize manufacturing processes, improve product design, revolutionize quality management and analyze motion. Mikrotron is ISO:9001 certified. Mikrotron is operated as a business unit of TKH Visions.