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Liu, Yingyi (Research Institute for Applied Mechanics, Kyushu University Kasuga) | Hu, Changhong (Research Institute for Applied Mechanics, Kyushu University Kasuga) | Yoshida, Shigeo (Research Institute for Applied Mechanics, Kyushu University Kasuga)
A time-domain method is developed for modeling the dynamics of a floating truss-structure wind turbine with multiple rotors mounted on the deck of the platform. In its hydrodynamic aspect, a hybrid panel-stick model is built up incorporating the potential flow theory to evaluate the wave inertia force and a Morison strip method to evaluate the wave drag force. The proposed analysis model is validated against a 1/50 scale test of a semi-submersible floating wind turbine, which was carried out in Kyushu University. Good agreement between the simulation results and the experimental data confirms the validity of the developed method. Further numerical simulations are performed in a set of wind and wave conditions to investigate the effect of wave drag force on the dynamics of the floating wind turbine. The results show that applying a hybrid panel-stick model is fairly effective to reduce the unphysical large resonant responses.
Semisubmersible type is one mainstream type of FWTs (floating wind turbines). An important issue of the semisubmersible foundations is to predict their motion responses, among which the heave response may be of a particular concern. At the natural frequencies, when using a potential flow based method, the semisubmersible normally endures remarkable resonant responses. The reason lies in that, near the boundary layer of the submerged part of the floating structure, the waveinduced drag force (which is a viscous force) has not been accounted for as that is usually done in a Navier-Stokes equation based solver. To include the viscous effect, the potential flow based method needs to be modified to some extent. On the other hand, although there have been some good works on determining the wave-induced loads upon a semisubmersible platform (e.g., Hooft, 1972; Mathisen et al., 1982), they are primarily based on the strip theory (or pure Morison equation) neglecting three-dimensional wave interactions between the Morison elements. Considering the co-existence of large-diameter columns and small-diameter members, it is advisable to employ a hybrid approach combining the potential flow theory and the Morison equation (Li and Yu, 2012). Liu et al. (2016) have done such a hybrid modeling in the frequency domain. The present work extends the idea to the time domain for a complex floating structure.
Space exploration has made significant advances over recent years. There are now many planned robotic exploration missions for the Moon, Mars and asteroids. Carrying enough fuel for future return journeys, particularly as necessary for human exploration missions poses a key challenge, or inefficiency of having to take all required fuel for return trip for the mission, incurring significant weight penalties and opportunity cost. The UAE has announced its
Recent exploration of Mars has identified some key in-situ raw materials regarding the presence of water ice, and an atmosphere for which the major component is carbon dioxide, comprising approx. 96%. The UAE's current Emirates Mars Mission "Hope" aims to build on that knowledge and increase our understanding with respect to the Martian climate. Future missions to Mars will lead to the development of in-situ resources. The associated technologies share many synergies with terrestrial activities concerning oil, gas and the energy industries. Furthermore, it is considered that the technology development for off-world resources may have significant advantages for terrestrial industry. The associated innovations and philosophy are consistent with the UAE's National Objectives regarding the furthering of a "Sustainable Environment and Infrastructure".
The largest US clean energy incubator has selected the city as the site for its second location, expanding Houston’s role as energy capital of the world beyond oil and gas. A recent report details national and global security threats related to climate change in the hopes that decision-makers and leaders will recognize the relationship between global warming and security. With a $10 million commitment from Shell, Rice University has launched Carbon Hub, a research initiative with the goal of creating a zero-emissions world by using oil and gas to create clean energy. French oil giant Total said it will not renew its membership of the American Fuel and Petrochemical Manufacturers association because the organization’s stance on climate issues does not align with its own. In this video from Bloomberg, Eldar Saetre, chief executive officer and president of Equinor, talks about the company's increased push into the offshore wind power market. Wood Mackenzie energy transition experts take on some of the trickiest questions about how to meet the world’s future energy needs while managing climate change.
Critics of the new rule call it a de facto ban on new drilling and completions that will affect large portions of the state’s undeveloped oil and gas properties. The tech giant and supermajor have been working on cloud solutions already, but in a new agreement, they will combine their talents to create new technologies for oil and gas as well as energy consumers. Two of Europe’s largest oil and gas producers will lead four offshore wind projects that together have the potential of powering 2 million homes. After 2 years of testing, Shell is going all in on using high-flying technology to catch methane leaks to reduce its overall emissions to less than 1%. Winning innovators focused on environment, safety, and operational efficiency.
Around $90 billion, or 40% of the revenue from the top 50 players in the global service market, could potentially be replaced by energy transition projects, such as clean energy infrastructure and renewable energy production development services. The Hydrogen Offshore Production project identifies an alternative to decommissioning by providing reuse options for offshore infrastructure. It aims to prove the feasibility of decentralized hydrogen generation, storage, and distribution to provide a bulk hydrogen solution. Five key steps for shaping renewable energy projects are discussed. As part of the contract, Wood will provide the topside modifications needed for the Snorre A and Gullfaks A platforms to integrate the Hywind floating wind park with existing systems powering the facilities.
The tech giant and supermajor have been working on cloud solutions already, but in a new agreement, they will combine their talents to create new technologies for oil and gas as well as energy consumers. This year’s outlook contains scenarios that suggest peak demand has already arrived because of a global pandemic and an accelerating energy transition. Two of Europe’s largest oil and gas producers will lead four offshore wind projects that together have the potential of powering 2 million homes. Supermajor announces actions to achieve net-zero ambition and reshape business. It also noted that it will not seek to explore in countries where it does not already have upstream activities.
In this study, an interactive method coupling a boundary element method (BEM) with a viscous flow solver solving the Reynolds-averaged Navier-Stokes (RANS) equations is applied to multiturbine interaction problems. The BEM is first applied to a single turbine problem to predict its performance with/without yaw in noncavitating/ cavitating conditions. Improved wake alignment models, the full wake alignment and the unsteady wake alignment, are used to align the blade wake. The former is adequate for steady state with zero yaw, and the latter is used for unsteady predictions in the case of nonzero yaw in the incoming flow. The BEM results are compared with the experimental measurements and the results from full-blown RANS simulations for a range of tip speed ratios. The comparisons show satisfactory agreement between the numerical and experimental approaches. Afterward, the BEM/RANS coupling method is applied to multiturbine interaction problems with different layouts and different turbine-to-turbine offsets in an axial turbine farm. The method is shown to work well in this multiturbine interaction problem because of the capability of using a strictly Cartesian grid in the RANS method, which minimizes the artificial diffusion and improves the numerical accuracy of long-range flow development. Representation of a turbine by the body force/mass source fields in the BEM/RANS coupling approach reduces the number of cells required for 3D full-blown RANS simulations, and therefore reduces the computational cost in an efficient way.