ISSN  0890-5487 CN 32-1441/P

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Numerical Study on the Aerodynamic and Fluid−Structure Interaction of An NREL-5MW Wind Turbine
Mi ZHAO, Wan-li YU, Pi-guang WANG, Yang QU, Xiu-li DU
2024, 38(3): 363 -378   doi: 10.1007/s13344-024-0030-1
[Abstract](0)
Abstract:
A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic performance. In this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics (CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier‒Stokes (RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid−structure interaction (FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction (FSI) model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.
Aero-Hydro-Elastic-Servo Modeling and Dynamic Response Analysis of A Monopile Offshore Wind Turbine Under Different Operating Scenarios
Shuang-yi XIE, Jian GAO, Yong-ran LI, Shu-xin JIANG, Cheng-lin ZHANG, Jiao HE
2024, 38(3): 379 -393   doi: 10.1007/s13344-024-0031-0
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This paper constructs a coupled aero-hydro-elastic-servo simulation framework for a monopile offshore wind turbine (OWT). In this framework, a detailed multi-body dynamics model of the monopile OWT including the gearbox, blades, tower and other components (nacelle, hub, bedplate, etc.) has been explicitly established. The effects of pile−soil interaction, controller and operational conditions on the turbine dynamic responses are studied systematically in time domain and frequency domain. The results show that (1) a comprehensive drivetrain model has the capability to provide a more precise representation of the complex dynamic characteristics exhibited by drivetrain components, which can be used as the basis for further study on the dynamic characteristics of the drivetrain. (2) The pile−soil interaction can influence the wind turbine dynamic responses, particularly under the parked condition. (3) The effect of the pile−soil interaction on tower responses is more significant than that on blade responses. (4) The use of the controller can substantially affect the rotor characteristics, which in turn influences the turbine dynamic responses. (5) The tower and blade displacements under the operational condition are much larger than those under the parked condition. The model and methodology presented in this study demonstrate potential for examining complex dynamic behaviors of the monopile OWTs. To ensure accuracy and precision, it is imperative to construct a detailed model of the wind turbine system, while also taking into account simulation efficiency.
Experimental Study on Vortex-Induced Vibration of Rough Risers Coupling with Interference Effect in Tandem Arrangement
Ze-bo HU, Zhen LIU, Peng LI, Hai-yan GUO, Xiao-hui REN, Hao HOU, Lian-hong HAO
2024, 38(3): 394 -407   doi: 10.1007/s13344-024-0032-z
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In order to study the response law of vortex-induced vibration (VIV) of marine risers under the combined action of roughness and interference effects, and to reveal the coupling mechanism of roughness and interference effects on the riser, a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined flume. The experiment characterized the risers’ roughness by arranging different specifications of attachments on the surface of the risers. Three rough risers with different roughness and smooth risers were arranged in tandem arrangement, with the rough risers arranged downstream. The experimental results indicate that the suppression of the attachments on the downstream risers’ vibration are more significant both in the CF and IL directions as the reduced velocity increases. For the downstream riser, the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced velocity. For the upstream risers, changes in the roughness and spacing ratio have an impact on their ‘lock-in’ region. When the roughness of downstream risers is relatively large (0.1300) and the spacing between risers is small (S/D=4.0), the reduced velocity range of ‘lock-in’ region in the CF direction of upstream risers is obviously expanded, and the displacement in the ‘lock-in’ region is severer.
Multiparameter Numerical Investigation of Two Types of Moving Interactions Between the Deep-Sea Mining Vehicle Track Plate and Seabed Soil: Digging and Rotating Motions
Peng-fei SUN, Hai-ning LYU, Jian-min YANG, Zhi-yong XU
2024, 38(3): 408 -423   doi: 10.1007/s13344-024-0033-y
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To ensure the safe performance of deep-sea mining vehicles (DSMVs), it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate. The rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed soil. In this study, a numerical simulation is conducted using the coupled Eulerian–Lagrangian (CEL) large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions: rotating condition and digging condition. First, a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ sampling. Subsequently, the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters, the grouser structure, the layered soil features and the soil heterogeneity. The results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed soil. Therefore, it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.
Coupling of RANS and BEM Solvers for Simulation of Propeller Behind the Hull in Full Appended Model
NAJAFI Saeed, POURMOSTAFA Mehdi, Peng-fei LIU
2024, 38(3): 424 -438   doi: 10.1007/s13344-024-0034-x
[Abstract](0)
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To design a propeller for ship power plant, the interaction between ship hull and propeller must be taken into account. The main concern is to apply the wake effect of ship stern on the propeller performance. In this paper, a coupled BEM (Boundary Element Method)/RANS (Renolds-Averaged Navier−Stokes) solver is used to simulate propeller behind the hull in the self-propulsion test. The motivation of this work is to develop a practical tool to design marine propulsion system without suffering long computational time. An unsteady boundary element method which is also known as panel method is chosen to estimate the propeller forces. Propeller wakes are treated using a time marching wake alignment method. Also, a RANS code coupled with VoF equation is developed to consider the ship motions and wake field effects in the problem. A coupling algorithm is developed to interchange ship wake field to the potential flow solver and propeller thrust to the RANS code. Based on the difference between hull resistance and the propeller thrust, a PI controller is developed to compute the propeller RPM in every time step. Verification of the solver is carried out using the towing tank test report of a 50 m oceanography research vessel. Wake factor and trust deduction coefficient are estimated numerically. Also, the wake rollup pattern of the propeller in open water is compared with the propeller in real wake field.
Hydrodynamic Assessment of A New Nature-Based Armour Unit on Rubble Mound Breakwater for Coastal Protection
SAFA Ehsan, MOJTAHEDI Alireza, MOHAMMADIAN Abdolmajid, YAGHIN Mohamad Ali Lotfollahi
2024, 38(3): 439 -452   doi: 10.1007/s13344-024-0035-9
[Abstract](0)
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This research proposes a novel nature-based design of a new concrete armour unit for the cover layer of a rubble-mound breakwater. Armour units are versatile with respect to shape, orientation, surface condition details, and porosity. Therefore, a detailed analysis is required to investigate the exact state of their hydraulic interactions and structural responses. In this regard, the performance results of several traditional armour units, including the Antifer cube, Tetrapod, X-block and natural stone, are considered for the first step of this study. Then, the related observed results are compared with those obtained for a newly designed (artificial coral) armour unit. The research methodology utilizes the common wave flume test procedure. Furthermore, several verified numerical models in OpenFOAM code are used to gain the extra required data. The proposed armour is configured to provide an effective shore protection as an environmental-friendly coastal structure. Thus it is designed with a main trunk including deep grooves to imitate the typical geometry of a coral type configuration, so as to attain desirable performance. The observed results and an analytic hierarchy process (AHP) concept are used to compare the hydraulic performance of the studied traditional and newly proposed (artificial coral) armour units. The results indicate that the artificial coral armour unit demonstrates acceptable performance. The widely used traditional armour units might be replaced by newer designs for better wave energy dissipation, and more importantly, for fewer adverse effects on the marine environment.
Configuration Synthesis and Grasping Performance Analysis of Multi-Loop Coupling Capture Mechanism for Launch and Recovery of Torpedo-Shaped Autonomous Underwater Vehicle
Guo-xing ZHANG, Xin-lu XIA, Jin-wei GUO
2024, 38(3): 453 -466   doi: 10.1007/s13344-024-0036-8
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Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles (AUVs). A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological features. Firstly, the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs, and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain synthesis. Secondly, the screw theory is employed to analyze the degree of freedom (DoF) of the capture mechanism. Then, the 3D model of the capture mechanism is established, and the kinematics and dynamics simulations are carried out. Combined with the capture orientation requirements of the capture mechanism, the statics and vibration characteristics analyses are carried out. Furthermore, considering the capture process and the underwater working environment, the motion characteristics and hydraulics characteristics of the capture mechanism are analyzed. Finally, a principle prototype is developed and the torpedo-shaped AUVs capture experiment is completed. The work provides technical reserves for the research and development of AUV capture special equipment.
An Innovative Coupled Common-Node Discrete Element Method-Smoothed Particle Hydrodynamics Model Developed with LS-DYNA and Its Applications
Zhong-xiang SHEN, Wen-qing WANG, Cheng-yue XU, Jia-xin LUO, Ren-wei LIU
2024, 38(3): 467 -482   doi: 10.1007/s13344-024-0037-7
[Abstract](0)
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In this study, a common-node DEM-SPH coupling model based on the shared node method is proposed, and a fluid–structure coupling method using the common-node discrete element method-smoothed particle hydrodynamics (DS-SPH) method is developed using LS-DYNA software. The DEM and SPH are established on the same node to create common-node DEM-SPH particles, allowing for fluid–structure interactions. Numerical simulations of various scenarios, including water entry of a rigid sphere, dam-break propagation over wet beds, impact on an ice plate floating on water and ice accumulation on offshore structures, are conducted. The interaction between DS particles and SPH fluid and the crack generation mechanism and expansion characteristics of the ice plate under the interaction of structure and fluid are also studied. The results are compared with available data to verify the proposed coupling method. Notably, the simulation results demonstrated that controlling the cutoff pressure of internal SPH particles could effectively control particle splashing during ice crushing failure.
Effect of Artificial Electric Field Surface by Wave-Driven Triboelectricity on Anti-Bioadhesion for Riser Protection
Peng YI, Hong-yuan QIU, Yong LI, Bao-ping CAI, MOSTAGHIMI Javad, Wen-jie ZHANG, Wen-sheng XIAO
2024, 38(3): 483 -490   doi: 10.1007/s13344-024-0039-5
[Abstract](0)
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Biofouling has been a persistent problem in marine riser system, resulting in energy waste and equipment damage. In this study, a kind of water wave-driven contact-mode flexible triboelectric nanogeneration has been prepared by using graphene-doped PDMS as dielectric friction material. When the graphene content is 2%, the average output voltage can reach 46 V under the contact frequency 10 Hz. The flexible triboelectric nanogeneration encapsulation module is impinged by water waves to generate alternating microelectric field on the riser surface and destroy the adhesion conditions of microorganisms during the biofilm stage. In the biofouling experiments at different stages, the biofouling area of the platymonas subcordiformis has been reduced by 53%, 62% and 61%. It provides a new idea for effective treatment of biofouling of mussels, oysters and barnacles attached to risers.
Technical Notes
Investigation of Maxima Assumptions in Modelling Tropical Cyclone-Induced Hazards in the South China Sea
Ze-guo WEN, Fu-ming WANG, Jing WAN, Fan YANG
2024, 38(3): 491 -504   doi: 10.1007/s13344-024-0038-6
[Abstract](0)
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The present study aims to examine the suitability of two commonly used assumptions that simplify modelling metocean conditions for designing offshore wind turbines in the South China Sea (SCS). The first assumption assumes that joint N-year extreme wind and wave events can be independently estimated and subsequently combined. The second one assumes peak wind and waves can be modelled as occurring simultaneously during a tropical cyclone (TC) event. To better understand the potential TC activity, a set of 10000 years synthetic TC events are generated. The wind field model and the Mike 21 spectral wave model are employed to model the TC-induced hazards. Subsequently, the effect of the assumptions is evaluated by analyzing the peak structural response of both monopile and semisubmersible offshore wind turbines during TC events. The results demonstrate that the examined assumptions are generally accurate. By assessing the implications of these assumptions, valuable insights are obtained, which can inform and improve the modelling of TC-induced hazards in the SCS region.
Hydrodynamic Characteristics of Undular Tidal Bores in the Qiantang River Based on Field Observations
Shu-yu ZHANG, Cun-hong PAN, Shen-yang ZHANG, Ruo-hua LI, Wen-long CHENG, Dong-feng XIE
2024, 38(3): 505 -518   doi: 10.1007/s13344-024-0040-z
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Understanding the undular tidal bores in the Qiantang River is essential for effective river management and maintenance. While breaking tidal bores have been studied extensively, reports on undular tidal bores in the Qiantang River remain limited. Furthermore, observed data on undular tidal bores fulfilling the requirements of short measurement time intervals, and spring, medium, and neap tide coverage, and providing detailed data for the global vertical stratification of flow velocity are quite limited. Based on field observations at Qige in the Qiantang estuary, we analyzed the characteristics of undular tidal bores. The results showed that the flooding amplitude (a) of the first wave is always larger than its ebbing amplitude (b). Moreover, the vertical distribution of the maximum flood velocity exhibites three shapes, influenced by the tidal range, while that of the maximum ebb velocity exhibites a single shape. During the initial phase of the flood tide in the spring and medium tides, the upper water body experiences multiple oscillating changes along the flow direction, corresponding to the alternating process of the crest and trough of the tide level upon the arrival of the tidal bore. The tidal range is a crucial parameter in tidal bore hydrodynamics. By establishing the relationship between hydrodynamic parameters and tidal range, other hydrodynamic parameters, such as the tidal bore height, maximum flood depth–averaged velocity, maximum flood stratified velocity at the measurement points, and duration of the flood tide current, can be effectively predicted, thereby providing an important reference for river management and maintenance.
A Time-Domain Numerical Simulation for Free Motion Responses of Two Ships Advancing in Head Waves
Su-yong PAN, Yong CHENG
2024, 38(3): 519 -530   doi: 10.1007/s13344-024-0041-y
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The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward speed. When solving problems within a time domain framework, the free water surface needs to simultaneously satisfy both the kinematic and dynamic boundary conditions of the free water surface. This provides conditions for adding artificial damping layers. Using the Runge−Kutta method to solve equations related to time. An upwind differential scheme is used in the present method to deal with the convection terms on the free surface to prevent waves upstream. Through the comparison with the available experimental data and other numerical methods, the present method is proved to have good mesh convergence, and satisfactory results can be obtained. The constant panel method is applied to calculate the hydrodynamic interaction responses of two parallel ships advancing in head waves. Numerical simulations are conducted on the effects of forward speed, different longitudinal and lateral distances on the motion response of two modified Wigley ships in head waves. Then further investigations are conducted on the effects of different ship types on the motion response.
Experimental Study on Towing Characteristics of Composite Bucket Wellhead Platform
Pu-yang ZHANG, Ying-fei LIU, Cong-huan LE, Hong-yan DING, Yu BAI
2024, 38(3): 531 -542   doi: 10.1007/s13344-024-0042-x
[Abstract](0)
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With the rapid development of large-scale development of marginal oilfields in China, simple wellhead platforms that are simple in structure and easy to install have become an inevitable choice in the process of oilfield development. However, traditional simple wellhead platforms are often discarded after a single use. In pursuit of a more cost-effective approach to developing marginal oilfields, this paper proposes a new offshore oil field development facility—an integrated bucket foundation for wellhead platform. To verify the safety of its towing behavior and obtain the dynamic response characteristics of the structure, this paper takes a bucket integrated bucket foundation for wellhead platform with a diameter of 40 m as the research object. By combining physical model tests and numerical simulations, it analyzes the static stability and dynamic response characteristics of the structure during towing, complete with the effects of the draft, wave height, wave period, and towing point height, which produce the dynamic responses of the structure under different influence factors, such as roll angle, pitch angle, heave acceleration and towing force as well as the sensibility to transport variables. The results show that the integrated bucket foundation for wellhead platform is capable of self-floating towing, and its movement is affected by the local environment, which will provide a reference for actual projects.

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