scholarly journals Dynamic response mitigation of floating wind turbine platforms using tuned liquid column dampers

2015 ◽  
Vol 373 (2035) ◽  
pp. 20140079 ◽  
Author(s):  
V. Jaksic ◽  
C. S. Wright ◽  
J. Murphy ◽  
C. Afeef ◽  
S. F. Ali ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Dynamic Performance ◽  
Weather Conditions ◽  
Liquid Column ◽  
Dynamic Responses ◽  
Floating Structure ◽  
Energy Devices ◽  
Wave Basin ◽  
Liquid Column Dampers ◽  
Output Only

In this paper, we experimentally study and compare the effects of three combinations of multiple tuned liquid column dampers (MTLCDs) on the dynamic performance of a model floating tension-leg platform (TLP) structure in a wave basin. The structural stability and safety of the floating structure during operation and maintenance is of concern for the performance of a renewable energy device that it might be supporting. The dynamic responses of the structure should thus be limited for these renewable energy devices to perform as intended. This issue is particularly important during the operation of a TLP in extreme weather conditions. Tuned liquid column dampers (TLCDs) can use the power of sloshing water to reduce surge motions of a floating TLP exposed to wind and waves. This paper demonstrates the potential of MTLCDs in reducing dynamic responses of a scaled TLP model through an experimental study. The potential of using output-only statistical markers for monitoring changes in structural conditions is also investigated through the application of a delay vector variance (DVV) marker for different conditions of control for the experiments.

scholarly journals Mapping Raindrop Erosion of GFRP Composite Wind Turbine Blade Materials: Perspectives on Degradation Effects in Offshore and Acid Rain Environmental Conditions

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Ghulam Rasool ◽  
Anna C. Middleton ◽  
Margaret M. Stack
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Acid Rain ◽  
Turbine Blade ◽  
Experimental Work ◽  
Turbine Blades ◽  
Erosive Wear ◽  
Weather Conditions ◽  
Wind Turbine Blade ◽  
Energy Devices

Abstract Climate change is rapidly forcing the world to create renewable energy that is capable of sustaining future energy requirements globally. The generation of renewable energy at a comparatively lower cost is a major challenge for this industry. Unforeseen weather conditions and environments such as offshore conditions or involving acid rain have a significant effect on the degradation of structural materials of renewable energy devices. For the investigation of droplet erosion behavior of the advanced material for the wind turbine blades, experimental work was carried out on a glass fiber-reinforced epoxy (GFRE) composite in different environments. A whirling arm rig was used for this experimental work in a laboratory-simulated rainfall conditions at a constant tip speed of the rotor blade. Three types of rainwater were used for a range of angles of attack from 15 to 90 deg in an increment of 15 deg. Erosive wear maps have been constructed to show the weather, location, environment, and raindrop erosion effects on the degradation of the wind turbine blade material. This map predicts that erosion in saline and acidic rain conditions acts synergistically on the blade material, which results in delamination between the fiber layers, pit formation, and development of micro stresses leading to loss of adhesion of reinforcement fibers.

A Novel Semi-Submersible Floating Wind Turbine Platform Design Based on Tuned Liquid Column Dampers

2019 ◽  
Author(s):  
Baijin Mao ◽  
Jili Sun ◽  
Zecheng Tang ◽  
Bo Feng ◽  
Weijie Zhang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Liquid Column ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Platform Design ◽  
Main Column ◽  
Liquid Column Dampers

Abstract Floating offshore wind turbine (FOWT) has been a hot research topic in recent years due to its great potential in deep sea wind energy harvesting. However, the floating platforms will introduce additional degrees of freedom to the system, which results in much more ultimate and fatigue loads onto the wind turbine structure compared with fixed bottom types. The load issue has been the major design challenge in developing FOWTs. In this paper, we report a novel semi-submersible supporting platform design, named MUsupport, aiming to improve the dynamic responses and reduce loads for FOWTs. The proposed semi-submersible MUsupport is mainly composed of one main column attached to the tower and four offset columns. Particularly, instead of simply filled with ballast water, the four columns act as four tuned liquid column dampers (TLCDs), and the oscillating liquid inside the TLCDs is supposed to help improve the dynamic responses of the semi-submersible platform, thus reducing the loads. The sizing of these TLCDs are determined by frequency analysis, and the detailed structural properties for MUsupport are described in this paper. Additionally, in order to better study the damping effects of the TLCDs, the dynamic model of MUsupport FOWT in the pitch-surge-heave plane is derived based on the Lagrangian approach, and free decay simulation test is performed. It can be observed from the results that the introduction of TLCDs will bring more damping to the system dynamics, which is helpful for FOWT load reduction. Note that this is only preliminary study, and future works will comprehensively investigate its hydrodynamic and mooring behaviors of MUsupport, and aero-hydro-servo-elastic numerical simulations or experimental tests should be performed to further verify its effectiveness.

scholarly journals Damage Monitoring of a Catenary Moored Spar Platform for Renewable Energy Devices

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3631 ◽  
Author(s):  
Deirdre O’Donnell ◽  
Jimmy Murphy ◽  
Vikram Pakrashi
Keyword(s):  
Renewable Energy ◽  
Structural Changes ◽  
Evidence Base ◽  
Experimental Investigations ◽  
Spar Platform ◽  
Energy Device ◽  
Energy Devices ◽  
Technological Readiness ◽  
Wave Basin ◽  
Structural Responses

Structural performance of renewable energy device platforms is central to their power generation in a reliable and competitive manner. However, there is a gap in research in the conceptual and experimental stages of such devices at lower technological readiness levels in terms of understanding of their structural responses. Uncertainties around knowledge related to damage conditions of such structures are under-researched and experimental investigations into the monitoring of performance of such structures are significantly needed. This research addresses this need and investigates various damage conditions in a scaled catenary moored spar platform in an ocean wave basin, exposed to typical wave conditions for the west coast of Ireland. A comparison of the monitored structural responses was carried out with respect to the undamaged experimental model. It was observed that while free decay tests were not useful to distinguish between various damage levels, a characterisation of the distribution of the responses can be relevant in identifying damages or significant structural changes. The work contributes to the much-needed experimental evidence base around structural health monitoring of renewable energy device platforms.

scholarly journals Dynamic response signatures of a scaled model platform for floating wind turbines in an ocean wave basin

2015 ◽  
Vol 373 (2035) ◽  
pp. 20140078 ◽  
Author(s):  
V. Jaksic ◽  
R. O'Shea ◽  
P. Cahill ◽  
J. Murphy ◽  
D. P. Mandic ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Control Strategies ◽  
Laser Doppler Vibrometer ◽  
Wind Farms ◽  
Recognition System ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Scaled Model ◽  
Wave Basin ◽  
Output Only

Understanding of dynamic behaviour of offshore wind floating substructures is extremely important in relation to design, operation, maintenance and management of floating wind farms. This paper presents assessment of nonlinear signatures of dynamic responses of a scaled tension-leg platform (TLP) in a wave tank exposed to different regular wave conditions and sea states characterized by the Bretschneider, the Pierson–Moskowitz and the JONSWAP spectra. Dynamic responses of the TLP were monitored at different locations using load cells, a camera-based motion recognition system and a laser Doppler vibrometer. The analysis of variability of the TLP responses and statistical quantification of their linearity or nonlinearity, as non-destructive means of structural monitoring from the output-only condition, remains a challenging problem. In this study, the delay vector variance (DVV) method is used to statistically study the degree of nonlinearity of measured response signals from a TLP. DVV is observed to create a marker estimating the degree to which a change in signal nonlinearity reflects real-time behaviour of the structure and also to establish the sensitivity of the instruments employed to these changes. The findings can be helpful in establishing monitoring strategies and control strategies for undesirable levels or types of dynamic response and can help to better estimate changes in system characteristics over the life cycle of the structure.

Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

2011 ◽  
Vol 250-253 ◽  
pp. 3822-3826 ◽  
Author(s):  
Xian Mai Chen ◽  
Xia Xin Tao ◽  
Gao Hang Cui ◽  
Fu Tong Wang
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wave Band ◽  
Wheel Load ◽  
Railway Line ◽  
Acceleration Rate ◽  
Time Histories ◽  
Railway System ◽  
Dynamic Performances ◽  
Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

scholarly journals Erratic electric power challenges in Africa and the way forward via the adoption of human biogas resources

2021 ◽  
pp. 014459872110036
Author(s):  
Moses E Emetere ◽  
O Agubo ◽  
L Chikwendu
Keyword(s):  
Renewable Energy ◽  
Electric Power ◽  
Technological Innovations ◽  
Government Agencies ◽  
Electric Power Supply ◽  
Energy Devices ◽  
Gas Generators ◽  
Financial Base ◽  
Energy Companies ◽  
The Way

This paper examines a broad spectrum of challenges plaguing electric power supply in Africa. The challenges have lingered very long that policymakers, energy companies, and government agencies have shown docility in tackling the problem headlong. The increasing human population and technological innovations are evidence that the more the problem lingers, the more it becomes insurmountable. In this paper, it was proposed the lingering challenges can be solved using the standalone system of power generation. The renewable energy option and its adaptability were highlighted to guide standalone users on the way forward. The growing population in Africa can be advantageous in generating biogas from human feaces. It was discovered that renewable energy devices are quite expensive; hence, the biogas option for cooking and powering gas generators seem to be sustainable as its technology can be modified to suit the users' financial base. Therefore, it is projected that if the human excretal biogas can be adopted, Africa will soon overcome its energy crisis through the doggedness of its standalone users.

scholarly journals Examining the Role of Disruptive Innovation in Renewable Energy Businesses from a Cross National Perspective

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4447
Author(s):  
Hokey Min ◽  
Yohannes Haile
Keyword(s):  
Renewable Energy ◽  
Natural Resources ◽  
Fossil Fuels ◽  
Weather Conditions ◽  
Disruptive Innovation ◽  
Production Costs ◽  
Developed Economies ◽  
Sustainable Value ◽  
National Perspective ◽  
The Impact

With a growing demand for safe, clean, and affordable energy, countries across the world are now seeking to create and rapidly develop renewable energy (RE) businesses. The success of these businesses often hinges on their ability to translate RE into sustainable value for energy consumers and the multiple stakeholders in the energy industry. Such value includes low production costs due to an abundance of natural resources (e.g., wind, water, sunlight), and public health benefits from reduced environmental pollution. Despite the potential for value creation, many RE businesses have struggled to create affordable energy as abundant as that which is produced by traditional fossil fuels. The rationale being that traditional RE sources emanating from natural resources tend to rely on unpredictable weather conditions. Therefore, to help RE businesses deliver sustainable value, we should leverage disruptive innovation that is less dependent on natural resources. This paper is one of the first attempts to assess the impact of disruptive innovation on RE business performances based on the survey data obtained from multiple countries representing both emerging and developed economies.

Strategic priorities for assessing ecological impacts of marine renewable energy devices in the Pentland Firth (Scotland, UK)

Marine Policy ◽  
2009 ◽  
Vol 33 (4) ◽  
pp. 635-642 ◽  
Author(s):  
Mark A. Shields ◽  
Lora Jane Dillon ◽  
David K. Woolf ◽  
Alex T. Ford
Keyword(s):  
Renewable Energy ◽  
Ecological Impacts ◽  
Energy Devices ◽  
Marine Renewable Energy
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