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Collaborating Authors
Reservoir Description and Dynamics
A Numerical Tool For the Integrated Analysis of Fixed-Bottom Offshore Wind Turbines
Loukogeorgaki, Eva (Department of Civil Engineering, Aristotle University of Thessaloniki (AUTh)) | Angelides, Demos C. (Department of Civil Engineering, Aristotle University of Thessaloniki (AUTh)) | Llorente, Carlos (McDermott Inc.)
ABSTRACT In this paper, a numerical tool (MicroSAS-OWT) for the integrated analysis of Offshore Wind Turbines (OWTs) with fixed-bottom support structure of arbitrary shape is presented. MicroSAS-OWT is developed through the coupling of FAST with MicroSAS. FAST is used for modeling the rotor nacelle assembly, while the tower and the support structure are modeled in MicroSAS. The interface of the two codes is ensured at the tower top. The tool is applied for the case of the NREL 5MW OWT that consists of a monopile support structure with rigid foundation, and is preliminary assessed through comparison of results with the corresponding ones obtained using FAST. Stress analysis of the tower and the support structure is also performed. INTRODUCTION Offshore wind energy represents a very promising kind of renewable energy source. Offshore Wind Turbines (OWTs) are considered nowadays as an attractive alternative solution to the onshore ones offering multiple benefits and addressing effectively the well-known obstacles and problems associated with the latter ones (Henderson et al., 2003; Breton and Moe, 2009; Esteban et al., 2011). The efficient exploitation of offshore wind energy necessitates the successful handling of several challenges related to developmental, economical and technological issues (Musial et al., 2006). Among these challenges, one of the most crucial is the development, investigation, assessment and adoption of new design concepts, especially for the support structure. These new design concepts will allow the placement of OWTs in deeper water and therefore, the operation of larger capacity OWTs. Considering the high complexity characterizing any OWT system, resulting from its inherent characteristics (e.g. variability and intense interaction of components) and from its operation in a complex environment, where different loading sources exist, the development/application of suitable numerical tools is critical for addressing efficiently the previously mentioned challenge.
- North America > United States (1.00)
- Europe (1.00)
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems > Platform design (1.00)
- Facilities Design, Construction and Operation > Facilities and Construction Project Management > Offshore projects planning and execution (0.91)
Strategic Development of Offshore Oil Production In Katakolo of Greece Under Multiple Criteria Considerations
Vamvinis, Athanasios (Department of Civil Engineering, Aristotle University of Thessaloniki (AUTh)) | Angelides, Demos C. (Department of Civil Engineering, Aristotle University of Thessaloniki (AUTh)) | Nikolaou, Constantinos (Kanergy Ltd) | Vagiona, Dimitra (Department of Spatial Planning and Development, Aristotle University of Thessaloniki (AUTh))
ABSTRACT The aim of the present paper is to investigate the feasibility and the type of method for oil production in the offshore area of Katakolo in western Greece. The strategic development of oil production analyzed herein is based on the following five factors:social conditions of the area, geological- geophysical conditions and oil deposit, socio-economic impact and financial considerations of the three proposed methods for oil production, methods for oil storage and transportation and, evaluation and comparison of the three oil production methods. Based on the proposed strategic framework and the results of the associated analysis, it can be stated that this effort is the first one to present the most efficient approach for developing the oil field in Katakolo, taking into account environmental constraints, socioeconomic factors and safety issues. INTRODUCTION The continuous increase of energy demand around the world stimulates interest in finding new oil fields. Oil exploitation represents a significant component of the strategic plans for energy requirements in many countries. While oil remains the dominant source of energy in Greece, exploration till now has been very limited and only in northern Aegean a low oil production exists since 1981. Greece can be considered the least oil explored country in the eastern Mediterranean region. The legal framework being applied since 1995 has led to this stagnation. The removal of this weakness was imperative. The enactment of the new Law 4001/2011 in combination with the preexisting one formed a new flexible legal framework. To overcome the stagnation, Greek authorities focused their efforts on an aggressive oil exploration campaign starting from non-exclusive seismic surveys in the Ionian and southern Cretan Sea and introducing three areas in the procedure of open door (MEECC, 2011). This procedure can be applied in Greece because the areas are permanently available, as they belong to the state.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Europe Government > Greece Government (0.48)
- Europe > Greece > Katakolo Field (0.99)
- Europe > Greece > Ionian Basin (0.99)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Production and Well Operations (1.00)
- Health, Safety, Environment & Sustainability > Environment (0.94)
- (2 more...)
ABSTRACT In this paper, the numerical investigation of a high deck open quay wall structure, supported on piles partially embedded in a porous embankment is presented. The governing equations solved are the Reynolds Averaged Navier-Stokes (RANS) equations of motion, while the two equation RNG turbulence transport model is applied. Parametric studies have been carried out for two different wave lengths, two structure clearances and two inclinations of the porous embankment. The forces exerted on the piles and on the underside of the deck of the quay structure due to waves are computed. The forces exerted on a single cylindrical pile computed with the present numerical model are compared with those calculated through the analytical equation of Morison. The computed pressures on a deck structure are compared with the experimental results of the investigation of other researchers. INTRODUCTION Quay walls are marine structures, generally parallel to the shore. They are broadly classified into two main types, quays with solid (closed) construction, like sheet and gravity walls with a solid vertical berthing face, and quays with an open construction, having a suspended deck supported on piles (British Standard's Institution, 1988). The type of the open quay construction is not in common use worldwide. However, in cases where there is need for wave absorption or there are favorable ground conditions, the open quay is preferable against the solid one (PIANC, 1997). The presence of the porous rubble slope in the structure of the open quay is responsible for the wave energy absorption and the reduction of the wave reflection. Furthermore, in ports with poor near surface soils but with good end bearing capacity for piles, an open pile supported quay would be most economical (Department of Defense, 2005). However, an open structure is proved to be more delicate than a solid one.
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Military > Army (0.94)
- Data Science & Engineering Analytics > Information Management and Systems (0.68)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics (0.47)
- Reservoir Description and Dynamics > Reservoir Characterization (0.46)
ABSTRACT: The risk of failing to achieve the acceptable performance (performance risk) of a free floating structure under the combined action of various wave frequencies is investigated in the frequency domain. Here, performance is quantified in terms of no exceedance of a threshold for the response level corresponding to each degree of freedom. Quantification of the performance risk is based on a Monte Carlo simulation technique. The numerical analysis of the free floating structure is carried out using a three dimensional hydrodynamic analysis. Several cases of different combinations of wave frequencies are investigated. The second-order hydrodynamic interactions of pertinent wave frequencies are considered in the analysis for each combination examined. Two issues are investigated, namely:performance and performance risk for the free floating structure considered. The performance and risk levels of the second-order solution are compared with the results of the corresponding first-order solution in order to investigate the significance of second-order quantities in the assessment of both performance and performance risk levels. According to the results generated by the present study, secondorder wave effects can generally strongly affect performance and performance risk levels. INTRODUCTION Considering the case of a free floating body subjected to the simultaneous action of two or more wave frequencies, non-linear hydrodynamic analysis needs to be carried since second-order wave effects can highly affect the response of the free floating body. This happens because several effects can hardly be predicted when using linear (first-order) theory, such as wave drifting and interaction between wave trains of different frequencies (Murao, 1960; Newman, 1990 and 2004 and McIver, 1992). For this reason, plenty of investigations, relevant to the analysis and computation of second-order wave effects have been carried out including among others Kosmeyer et al. (1988), Lee (1991) and Kim M.H. (1992 and 1993).
- Europe (1.00)
- North America > United States (0.28)
- Asia > Japan (0.28)
- Management > Risk Management and Decision-Making (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (1.00)
- Reservoir Description and Dynamics > Reservoir Simulation (0.88)