March 2021 OES Beacon

IEEE OES SBC NAOME Poster Competition

Roberto Ravenna (IEEE OES SBC Vice president), Marvin Wright (IEEE OES SBC Webmaster), Olena Karpenko (IEEE OES SBC Chair), Andrea Coraddu (IEEE OES SBC Advisor)

Figure 1 Panel members

Introduction of event

Above all, Covid19 is pushing researchers to harness the power of the internet and online communication tools. Building on the renewed confidence in organising online events, the IEEE Oceanic Engineering Society (OES) Student Branch Chapter (SBC) of the Naval Architecture, Ocean and Marine Engineering (NAOME) Department of the University of Strathclyde, hosted an online project presentation competition dedicated to outstanding final year students of the academic year. The IEEE OES Strathclyde SBC, founded in 2018 under the group of enthusiastic and dedicated PhD students and academic staff of NAOME department, is a thriving group of young and senior marine researchers with currently around 20 active members. Next to providing a community space for young researchers and students, it supports and organises various events across campus. The society is having great success in organising the workshops, giving an opportunity for students to learn and enlarge their knowledge on state-of-the-art topics. Despite the many activities held during the year and challenges all the world is facing, the OES organises the annual poster competition to provide a place for students to showcase their final year bachelor work and practice presentation skills while receiving feedback from professionals on their hard work at the end of the degree.

Figure 1 Panel members

Forced by the COVID 19 pandemic, the format of the event was an online competition and presentation. Everyone adapted well to the situation and made full use of the online video conference. The virtual event organised at the end of the academic year proved to be popular with people joining from across the University. Out of 50 students, the senior members of society, led by SBC Advisor, Dr Andrea Coraddu, selected three participants based on their outstanding performance in the current year’s graduate poster presentation at the NAOME department at the University of Strathclyde. Each of the selected students had to present their work within 15 minutes with additional 10 minutes time for Q&A. For this year’s event Prof John Watson from the University of Aberdeen, the IEEE Oceanic Engineering Society (OES) Vice President for OCEANS conferences, kindly joined as a judge. He was joined in the jury by Dr James Irvine (IEEE SBC Councillor), Dr Andrea Coraddu (IEEE OES SBC Advisor) and Olena Karpenko (IEEE OES SBC Chair) from the University of Strathclyde.

It ran for half a day without any interruptions and has left organisers, judging panel and students with a happy feeling.

IEEE-OES is engaged in all aspects of science, engineering, and technology that address research, development, and operations pertaining to all bodies of water. This is fully reflected in the participating poster topics. The three presentations led to interesting discussions during each Q&A time. All students have shown outstanding efforts in their work and have impressed with the produced results in the given time. The panel had the difficult task to choose the winner and have decided for Yi Huang, who has shown particular detail in his results and presentation. He has since managed to publish his work at a conference (ISOPE-I-20-1207).

While the OES SBC Strathclyde hopes to hold this event in person again, the virtual event has shown that it can be completed successfully online. We would like to congratulate the three students on their excellent final year projects and graduating since the event. In the following you can find the abstracts of the three finalists:

Yi Huang (Supervisors: Dr Lai-Bing Jia, University of Strathclyde)
Topic: Plastic Debris in Waves an Experimental Study

Plastic waste in the ocean is one of the most consequential issues of humankind. Despite the horrifying situation, little knowledge has people acquired about the effect of local wave on plastic particle movement. In this study, the issue of local wave effect has been studied to investigate the trajectories and distribution of the plastic particles on the free water surface. A series of model tests have been performed using the old water tank in Henry Dyer building for the regular wave tests. Factors including a single and a flock plastic, different frequencies are considered, and for irregular wave tests, five different sea states are designed to be tested in the new water tank in the Kelvin Hydrodynamic Lab (KHL). The presented experimental results showed a correlation between the wave frequency and the final position of the plastic particles. Specifically speaking, under the circumstance of fixed altitude and regular wave, when the frequency is higher than 1.2Hz, the majority of the particles will end up on shore, and a higher frequency will lead to a faster landing. Similar phenomenon was observed in the irregular wave test, where the possibility of landing at lower sea states are higher than that at higher sea states. Results and observations gained from this project can contribute to our understanding of the marine pollution issue and help predicting the landing time of waste in coastal area as well as creating a more accurate estimation of the distribution of ocean plastic in seabed.

Catalina-Georgiana Francu (Supervisors: Dr Maurizio Collu, University of Strathclyde)
Topic: Impact of the Non-Linear Viscous Drag Damping on the Optimisation of Floating Support Structures for Offshore Wind Turbines in the Frequency-Domain

The floating offshore wind industry has consistently evolved during the past years. The society is now more aware of the damaging effects of climate change on the environment, so renewable and less polluting energy sources have become a common topic even in the political space.

The existing structures for offshore floating wind turbines were shaped by the oil and gas industry, so it is high time other options were explored. This report is a contribution to a larger project that aims to do just that. By carefully considering the difference between the two fields, the FEDORA Multidisciplinary Analysis and Optimisation Framework was developed by the supervisors and other researchers in order to discover unique configurations that would ideally have a reduced structural mass, leading to substantial cost savings. This code investigates only the hydrodynamic potential flow problem, but it may not describe the behaviour of the platform accurately in all sea states. Consequently, the non-linear viscous effects had to be included. A viscous damping matrix was created by linearising the drag damping term in Morison’s Equation following the method that was introduced by Borgman. The water particles velocities induced by the wave were neglected. Thus, the linearised damping coefficients (surge-surge, surge-pitch/pitch-surge, pitch-pitch) were calculated as functions of the standard deviation of the body velocity. Simulations were conducted for two load cases, one of which was chosen to be more energetic. It was concluded that the addition of the drag damping leads to a 1% reduction in the structural mass in the harsher environmental condition and to a reduction of only 0.03% in the less severe one. However, the surge and pitch motions of the structure are always greatly impacted. In the more severe environmental conditions, the surge RAO at the natural frequency (0.05 rad/sec) was reduced by 71.1% when the viscous effects were considered. The pitch RAO at 0.13 rad/sec was reduced by 79.5% leading to a shift in the pitch natural frequency. The absolute values of the surge-surge, pitch-pitch, surge-pitch/pitch-surge elements from the viscous damping matrix were found to be 125%, 118% and 121% greater in the first load case than in the second one. Therefore, the drag damping has a substantial influence on the motions of the platform in some extreme sea states.

Vaszilisz Mitropulosz (Supervisors: Dr Andrea Coraddu)
Topic: Response Amplitude Operator Prediction of unconventionally parametrised SPAR type Floating Offshore Wind Turbines

The floating offshore wind sector expected to expand in the coming years, but the technology applied in their substructure shapes are not matured yet. In recent years different platform configurations were designed. In most case, the configurations follow a conventional parametrisation which was inherited from the Oil and Gas industry. Therefore, their optimisation already inherited an ample bias and parametric constraints, which means that there is a significant margin for improvements in the FOWT system performance and cost, which can be done through substructure optimisation. An optimisation process may need hundreds of thousands of iterations to find the optimum point successfully. For this purpose, an unconventional parametrisation was created, where the cylindrical shape of SPAR type Floating Offshore Wind Turbine (FOWT) substructure was replaced by five truncated cones placed on each other. However, during the construction of the optimisation algorithm, the prediction of the Response Amplitude Operators (RAO) of the floating system seemed to be computationally too expensive to perform the task effectively. An efficient way to minimise the computational overload, is to replace the costly simulation model with a cheaper-to-run metamodel. Therefore, this project deals with a potential metamodel generation, which can predict the RAOs of unconventionally parametrised SPAR type floating wind turbine.