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The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform

Mingming Zhang - One of the best experts on this subject based on the ideXlab platform.

  • load control of floating wind turbine on a tension Leg Platform subject to extreme wind condition
    Renewable Energy, 2020
    Co-Authors: Mingming Zhang, Jingxi Tong
    Abstract:

    Abstract This paper mainly focuses on the control of a typical extreme load, i.e. Extreme Coherent Gust with Direction Change (ECD) and Normal Sea State (NSS), on a floating wind turbine (FWT) with a Tension-Leg-Platform (TLP), following the International Electro-technical Commission (IEC) standard. Using an integrated aero-hydro-servo-elastic code, the control action was implemented through the local perturbations of the Deformable Trailing Edge Flaps (DTEFs) on the blade surfaces and thus to the whole FWT. Investigations were separately conducted in four phases, depending on the complex yaw or/and pitching functions of the turbine. It was found that although the uncontrolled extreme loads on the FWT, which mainly originated from the combined influences of ECD and NSS, were rather strong, the smart rotor control very effectively reduced the standard deviations in the primary fluctuating loads on the blades, driving-chain components, tower and TLP by up to 10–35%. The good control performance lay in the altered flow-blade interactions from in-phased to anti-phased situations at dominant mode frequencies, thus significantly impairing their coherences, and subsequently the loads on the blades and other interrelated elements of the turbine system.

  • smart control of fatigue loads on a floating wind turbine with a tension Leg Platform
    Renewable Energy, 2019
    Co-Authors: Mingming Zhang
    Abstract:

    In this paper, the smart fatigue load control of a representative floating wind turbine (FWT) with a tension-Leg-Platform was numerically investigated using our newly integrated aero-hydro-servo-elastic code. The control was achieved by introducing a local, fast and efficient closed-loop system based on deformable trailing edge flap (DTEF) activation near the tip of each blade, and as a result, it was able to effectively suppress the unstable loads on the critical components, as well as improve the general performances of FWT. The control effectiveness lies in the great impairment of original synchronized wind-rotor relationship by controllable DTEFs. This significantly decreased the combined effects of wind, waves and primary modes of blade, driving-chain components, tower and TLP Platform, and subsequently attenuated the main fatigue loads on them. The effect of the control mechanism became more drastic as the investigation focused on the case beyond the rated wind velocity. In addition, the research findings showed the crucial role that the wind-wave-rotor relationship played during the development of smart rotor controller.

Jingxi Tong - One of the best experts on this subject based on the ideXlab platform.

  • load control of floating wind turbine on a tension Leg Platform subject to extreme wind condition
    Renewable Energy, 2020
    Co-Authors: Mingming Zhang, Jingxi Tong
    Abstract:

    Abstract This paper mainly focuses on the control of a typical extreme load, i.e. Extreme Coherent Gust with Direction Change (ECD) and Normal Sea State (NSS), on a floating wind turbine (FWT) with a Tension-Leg-Platform (TLP), following the International Electro-technical Commission (IEC) standard. Using an integrated aero-hydro-servo-elastic code, the control action was implemented through the local perturbations of the Deformable Trailing Edge Flaps (DTEFs) on the blade surfaces and thus to the whole FWT. Investigations were separately conducted in four phases, depending on the complex yaw or/and pitching functions of the turbine. It was found that although the uncontrolled extreme loads on the FWT, which mainly originated from the combined influences of ECD and NSS, were rather strong, the smart rotor control very effectively reduced the standard deviations in the primary fluctuating loads on the blades, driving-chain components, tower and TLP by up to 10–35%. The good control performance lay in the altered flow-blade interactions from in-phased to anti-phased situations at dominant mode frequencies, thus significantly impairing their coherences, and subsequently the loads on the blades and other interrelated elements of the turbine system.

Jack Y.k. Lou - One of the best experts on this subject based on the ideXlab platform.

  • STABILITY OF VORTEX-INDUCED OSCILLATIONS OF TENSION Leg Platform TETHERS
    Ocean Engineering, 1992
    Co-Authors: Yanqiu Dong, Geng Xie, Jack Y.k. Lou
    Abstract:

    Abstract The study concerns possible occurrence of instability and bifurcation of vortex-induced transverse oscillations for tension Leg Platform tethers. The tether is modeled by a simple nonautonomous system with quadratic damping and parametric excitation. Krylov-Bogoliubov-Mitropolsky method was used to predict the stability of the system. Regions of unstable solutions, phase plane portraits and Poincare maps were constructed to illustrate the response of the tether.

  • Vortex-induced nonlinear oscillation of tension Leg Platform tethers
    Ocean Engineering, 1991
    Co-Authors: Yanqiu Dong, Jack Y.k. Lou
    Abstract:

    Abstract The paper concerns the nonlinear oscillation of tension Leg Platform tethers induced by vortex shedding in a combined wave and current field. Quadratic damping and parametric excitation are included in the mathematical model. Only the vortex-induced oscillations normal to the wave and current are considered. However, the method used can also be applied to study the in-line oscillations due to waves. Stability analysis of the nonlinear system will be presented in a separate paper. A multiple-term Galerkin's method is used in the numerical computations. Results for the CONOCO's Hutton TLP are presented to illustrate the importance of multiple-term solutions under lock-on conditions. The effects of the drag and lift coefficients and the frequencies of the waves and parametric excitations have also been investigated.

Patrick Bar-avi - One of the best experts on this subject based on the ideXlab platform.

  • Nonlinear Dynamic Response of a Tension Leg Platform
    Journal of Offshore Mechanics and Arctic Engineering, 1999
    Co-Authors: Patrick Bar-avi
    Abstract:

    Of the classes of offshore structures, the tension Leg Platform (TLP) is particularly well suited for deepwater operation. The structure investigated in this paper is assumed to consist of a flexible cable attached to a buoyant deck at the top. The cable is modeled as a beamlike continuous system subjected to wave, current, and wind forces. The derivation of the nonlinear equations of motion include nonlinearities due to geometry as well as due to wave forces. The equations of motion are solved and the TLP’s response to various environmental conditions and other physical parameters is evaluated.

R. Panneer Selvam - One of the best experts on this subject based on the ideXlab platform.

  • Response analysis of tension-based tension Leg Platform under irregular waves
    China Ocean Engineering, 2016
    Co-Authors: D. S. Bhaskara Rao, R. Panneer Selvam
    Abstract:

    Tension Leg Platform (TLP) is a hybrid structure used as oil drilling and production facility within water depths of 1200 m. The extension of this TLP concept to deeper waters is a challenge and warrants for some innovative design concepts. In this paper, a relatively new concept of TLP which is christened as Tension-Based Tension Leg Platform (TBTLP) and patented by Srinivasan (1998) has been chosen for study. Response analysis of TLP with one tension base under irregular waves for three different sea states has been performed using hydrodynamic tool ANSYS® AQWA™. Results are reported in terms of RAOs, response spectrums for surge, heave and pitch degrees of freedom from which spectral statistics have been obtained. The statistics of TBTLP have been compared with TLPs (without tension base) for two different water depths to highlight the features of the new concept. The effect of viscous damping and loading effects on the RAOs are also investigated.

  • EXPERIMENTAL INVESTIGATIONS ON TENSION BASED TENSION Leg Platform (TBTLP)
    Journal of Naval Architecture and Marine Engineering, 2014
    Co-Authors: R. Panneer Selvam, Nagan Srinivasan
    Abstract:

    Tension Leg Platforms (TLPs) are one of the reliable structures for offshore industry in deep waters because of its motion characteristics in heave, roll and pitch degrees of freedom. Heave motion is very important in offshore facilities and have to kept as minimum as possible. As the water depth increases TLPs suffers from some limitations and hence has to be modified to cater to deeper waters. One such concept proposed is Tension Based Tension Leg Platform (TBTLP). In this paper, experimental investigations carried out on a scaled model of a Tension Based Tension Leg Platform in regular waves are reported. This is the first ever experiments that was carried out on a scaled model of the new concept. To investigate the effect of Tension Base, experiments were also conducted on the TLP (without Tension Base) in two different water depths. RAOs have been compared for surge and heave dof of TLP and TBTLP. Numerical modeling of the TLP and TBTLP responses using ANSYS AQWA software are included as well for comparisons. DOI: http://dx.doi.org/10.3329/jname.v11i2.17341

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