The inaugural issue of ASME Journal of Offshore Mechanics and Arctic Engineering was launched in February 1987. The venerable (late) Professor Subrata K. Chakrabarti, who was the Journal's Editor over its first 10 years, wrote this in an editorial in his last issue as Editor in August 1997:
“The principal strength of the Journal is its highly technical contents, for which I have received many compliments on behalf of the OMAE Division from readers and other technical editors within ASME. This is primarily due to the dedication of the Associate Technical Editors, international expert reviewers, and contributing authors.”
The ASME Journal of Offshore Mechanics and Arctic Engineering has continued, over its more than 30 years under the able stewardship of three different Editors (Subrata K. Chakrabarti, Stephen Liu, and Solomon C. Yim), to provide a forum for the exchange of ideas, peer-reviewed research, and technology developments that advance the state of knowledge on all aspects of analysis, design, and technology development in ocean, offshore, and arctic engineering. As the new Editor, since January 2018, I am looking to maintain this appeal of the journal to the community and will always welcome your ideas for improvement.
As noted above, it is indeed the dedication of Associate Editors, aided by conscientious reviewers, that has helped the Journal document significant developments in research and practice in related fields over the years. To acknowledge these contributions of the Associate Editors, I wish to periodically provide brief biographical sketches of these individuals, highlighting their expertise areas and accomplishments. In this issue, I present to you two Associate Editors—Dr. Zhen Gao, a Professor of Marine Structures at the Norwegian University of Science and Technology in Trondheim, Norway; and Dr. Amy Robertson, a Senior Engineer at the National Renewable Energy Laboratory in Boulder, CO.
Associate Editor, Dr. Zhen Gao
Professor Zhen Gao (Fig. 1) is a Professor of Marine Structures at the Department of Marine Technology (DMT), Norwegian University of Science and Technology (NTNU). He obtained his Bachelor's and Master's degrees from Shanghai Jiao Tong University in China in 2000 and 2003, respectively, and his Ph.D. degree from NTNU in 2008. After earning his Ph.D., he first worked as a postdoctoral researcher and later as an adjunct professor at NTNU, before he joined the faculty as a professor in 2015. Dr. Gao is currently a deputy head for research at DMT, NTNU. He has published more than 178 peer-reviewed articles. At NTNU, he has been involved in the supervision or co-supervision of 18 Ph.D. candidates and more than 40 Master's students.
Professor Gao's main research areas include the coupled dynamic analysis of offshore renewable energy devices; marine operations related to installation and maintenance of offshore wind turbines; probabilistic modeling and analysis of wind- and wave-induced loads and load effects on offshore structures; fatigue and ultimate structural reliability assessment of offshore platforms and mooring systems. To mention only one area of interest, Professor Gao and his colleagues have developed numerical methods and modeling techniques in nonlinear time-domain simulations for determining internal loads in structural components of floating wind turbines, so that design checks for such structures may be easily performed. An example of a braceless semisubmersible floating wind turbine and a comparison between numerical simulations and experimental measurements of the bending moment at one side column is presented in Fig. 2.
Braceless semisubmersible concept and comparison of bending moment at one side column between the numerical and the experimental results
Braceless semisubmersible concept and comparison of bending moment at one side column between the numerical and the experimental results
In addition to research contributions, Professor Gao has served as the Chairman for two terms (2012–2015 and 2015–2018) for the Specialist Committee V.4 Offshore Renewable Energy at the International Ship and Offshore Structures Congress (ISSC). He devotes a considerable amount of time in reviewing and editorial work for various journals and conferences.
In Professor Gao's own words, “Offshore wind energy development will become more challenging especially with regard to the design, transport and installation of large turbines (10-20 MW) for use with floating support structures. And, with increasing availability of measurements and monitoring data from the existing wind farms, there is a need for developing, validating and applying data-driven models, in addition to physics-based models, for design, maintenance planning as well as lifetime extension of offshore wind turbines.” He also believes that novel offshore and coastal structures with increasing complexity and functionality will provide new engineering challenges to the broader research community. A recent example is the development of floating bridges for crossing Norwegian fjords; the inhomogeneous wind and wave fields, the flexibility of floating bridges, and the strong coupling between the wind, wave, and current loads suggest a need to go beyond the use of state-of-the-art numerical methods/tools and experimental techniques in the dynamic response analysis of such novel structures. Similar considerations apply to aquaculture plants or fish farms, which has seen an increased interest in recent years.
Associate Editor, Dr. Amy Robertson
Dr. Amy Robertson (Fig. 3) is a Senior Engineer at the National Renewable Energy Laboratory (NREL) in the U. S., where she has worked since 2010. She is a member of the offshore wind team and leads efforts related to the verification and validation of coupled wind/wave/structural dynamics models. She holds a Ph.D. in Aerospace Engineering from the University of Colorado, where she developed innovative algorithms for structural system identification using wavelet transforms. Prior to joining NREL, Amy worked as an independent consultant for 3 M in Boulder, CO, and as a Technical Staff Member at Los Alamos National Laboratory in New Mexico. Her diverse work experience has included offshore wind system modeling, verification, and validation (including uncertainty assessment); data interrogation of mechanical responses; structural health monitoring of civil structures; finite-element and rigid-body modeling; and the analysis of medical computed tomography (CT) data. Across her diverse experience, Dr. Robertson has co-authored more than 100 technical reports, conference papers, and journal articles. She has also written three book chapters.
Since 2011, Dr. Robertson has served as co-leader of the International Energy Agency (IEA) Wind Task 30, a research effort focused on the verification and validation of offshore wind design tools. She spearheaded the development of two project extensions, OC5 and OC6. The new Offshore Code Comparison Collaboration, Continued, with uncertainty (OC6) project, which began in 2019, will perform focused validation projects to address physical phenomena known to have a large impact on the global response behavior of offshore wind systems. High-fidelity modeling tools will be incorporated in the planned validation efforts and will seek to improve engineering-level models, which are an emphasis of Task 30. The OC6 project brings together a diverse group of international participants across the offshore wind industry, including wind turbine designers, offshore system designers, certifiers, and experimental testers to work collaboratively on improving coupled offshore wind modeling tools.
To support the OC6 work, Dr. Robertson has collaboratively developed a series of validation campaigns on scaled floating wind systems in wave tanks. This work is designed to better understand the hydrodynamic loads on floating wind systems, whose structures resemble those used in oil and gas, but whose contrasting dimensions affect the feasibility of conventional hydrodynamic modeling approaches. The newest validation campaign concentrates on component-level hydrodynamic loads and on examining the ability of engineering design tools to model loads for nearby structural members in close proximity, such as heave plates and multiple buoyancy columns. An integral aspect of these projects is the development of appropriate methods and quantification of the associated uncertainty in experimental tests, which has not yet been adequately addressed in the field. Dr. Robertson is applying her knowledge of uncertainty assessment to new areas, such as assessing the most sensitive parameters for load predictions in land-based wind systems (Fig. 4).
A team of researchers (Erin Bachynski, Sebastien Gueydon, and Fabian Wendt) with Amy Robertson (second from left) at MARIN's wave basin during the performance of scaled hydrodynamic loading tests on a floating wind semisubmersible
A team of researchers (Erin Bachynski, Sebastien Gueydon, and Fabian Wendt) with Amy Robertson (second from left) at MARIN's wave basin during the performance of scaled hydrodynamic loading tests on a floating wind semisubmersible
In Dr. Robertson's words, “Offshore wind has significant potential to provide power to regions of the world where other sustainable energy sources are not readily available or where space on land is constrained. While offshore wind is a mature market in Europe and costs are rapidly decreasing on a global basis, innovative and optimized offshore wind technologies have the potential to reduce costs further. Validated design tools will enable rapid technology innovation and the resulting cost reduction in the offshore wind industry.”
