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Electroacupuncture with different waveforms for primary dysmenorrhea:A randomized controlled trial
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作者 Xiaona Wu Jingxue Yuan +5 位作者 Jinxia Ni Xiuli Ma Ziniu Zhang Yini Hua Juwei Dong Bob Peng Wang 《Journal of Traditional Chinese Medical Sciences》 CAS 2024年第3期357-362,共6页
Objective:To observe and compare the clinical effects of different electroacupuncture waveforms on primary dysmenorrhea.Methods: This was a prospective,randomized,three-group,parallel-controlled trial.Participants wit... Objective:To observe and compare the clinical effects of different electroacupuncture waveforms on primary dysmenorrhea.Methods: This was a prospective,randomized,three-group,parallel-controlled trial.Participants with primary dysmenorrhea were randomly divided into dense-sparse wave,continuous wave,and discontinuous wave groups in a 1:1:1 ratio.Two lateral Ciliao(BL 32)points were used.All three groups started treatment 3–5 days before menstruation,once a day for six sessions per course of treatment,one course of treatment per menstrual cycle,and three menstrual cycles.The primary outcome measure was the proportion with an average visual analog scale(VAS)score reduction of≥50%from baseline for dysmenorrhea in the third menstrual cycle during treatment.The secondary outcome measures included changes in dysmenorrhea VAS scores,Cox Menstrual Symptom Scale scores and the proportion of patients taking analgesic drugs.Results: The proportion of cases where the average VAS score for dysmenorrhea decreased by≥50%from baseline in the third menstrual cycle was not statistically significant(P>.05).Precisely 30 min after acupuncture and regarding immediate analgesia on the most severe day of dysmenorrhea,there was a statistically significant difference in the dense-sparse wave group compared with the other two groups during the third menstrual cycle(P<.05).Additionally,there was a statistically significant difference between the dense-sparse wave and discontinuous wave groups 24 h after acupuncture(P<.05).Conclusions: Waveform electroacupuncture can alleviate primary dysmenorrhea and its related symptoms in patients.The three groups showed similar results in terms of short-and long-term analgesic efficacy and a reduction in the number of patients taking analgesic drugs.Regarding achieving immediate analgesia,the dense-sparse wave group was slightly better than the other two groups. 展开更多
关键词 waveFORMS Ciliao(BL 32) ELECTROACUPUNCTURE Primary dysmenorrhea randomized controlled trial Dense-sparse waves Continuous waves Discontinuous waves
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Oblique and Multi-Directional Random Wave Loads on Vertical Breakwaters 被引量:3
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作者 俞聿修 李本霞 张宁川 《海洋工程:英文版》 2003年第2期189-202,共14页
Extensive 3-D model tests have been performed to study the effects of wave obliquity and multi-directionality on the wave loads acting on vertical breakwaters. The variation of horizontal and uplift forces acting on a... Extensive 3-D model tests have been performed to study the effects of wave obliquity and multi-directionality on the wave loads acting on vertical breakwaters. The variation of horizontal and uplift forces acting on an unit length of a breakwater with wave direction, the longitudinal distribution of wave forces, as well as the longitudinal load reduction are analyzed. Some empirical formulae of the longitudinal distribution coefficient and the longitudinal load reduction factor are presented for practical use. 展开更多
关键词 vertical breakwaters oblique wave multi-directional random wave longitudinal distribution wave forces longitudinal load reduction
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Study on Measurement Methods of Multi-Directional Waves—Wave Gauge Array Method 被引量:5
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作者 Yu Yuxiu Liu Shuxue Prof. Department of Civil Engineering, Dalian University of Technology, Dalian Assistant Researcher, Department of Civil Engineering, Dalian University of Technology, Dalian 《China Ocean Engineering》 SCIE EI 1992年第2期233-242,共10页
Measuring multi-directional waves with the wave gauge array is one of the fundamental and easily realised methods. In this paper, the wave gauge array is described and the effects of the gauge spacing, the array orien... Measuring multi-directional waves with the wave gauge array is one of the fundamental and easily realised methods. In this paper, the wave gauge array is described and the effects of the gauge spacing, the array orientations, etc. of the three array arrangements, i. e., linear array, T-type array and pentagon array, on the resolution of the directional spreading of waves, are investigated experimentally. This study can be used as a reference in the experimental study and the field measurement of directional waves. 展开更多
关键词 multi-directional waves measurement method directional spectrum wave gauge array
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Three-Dimensional Model Test for Port Engineering with Multi-Directional Waves 被引量:1
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作者 Yu Yuxiu Liu Shuxue Professor, State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology (DUT), Dalian 116024 Assistant Researcher, State Key Laboratory of Coastal and Offshore Engineering, DUT, Dalian 116024 《China Ocean Engineering》 SCIE EI 1994年第1期51-66,共16页
-The necessity of using irregular waves, especially multi- directional waves to conduct three-dimensional model tests for port engineering and the test method are described in this paper through an example of model te... -The necessity of using irregular waves, especially multi- directional waves to conduct three-dimensional model tests for port engineering and the test method are described in this paper through an example of model test for a port. The test results show that a deep navigation channel has a large effect on the waves in front of the breakwater near the port entrance and on the wave condition in the port. 展开更多
关键词 port engineering three-dimensional model test irregular waves multi-directional waves
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Numerical Simulation of Multi-Directional Random Wave Transformation in a Yacht Port 被引量:3
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作者 JI Qiaoling DONG Sheng +1 位作者 ZHAO Xizeng ZHANG Guowei 《Journal of Ocean University of China》 SCIE CAS 2012年第3期315-322,共8页
This paper extends a prediction model for multi-directional random wave transformation based on an energy balance equation by Mase with the consideration of wave shoaling, refraction, diffraction, reflection and break... This paper extends a prediction model for multi-directional random wave transformation based on an energy balance equation by Mase with the consideration of wave shoaling, refraction, diffraction, reflection and breaking. This numerical model is improved by 1) introducing Wen's frequency spectrum and Mitsuyasu's directional function, which are more suitable to the coastal area of China; 2) considering energy dissipation caused by bottom friction, which ensures more accurate results for large-scale and shallow water areas; 3) taking into account a non-linear dispersion relation. Predictions using the extended wave model are carried out to study the feasibility of constructing the Ai Hua yacht port in Qingdao, China, with a comparison between two port layouts in design. Wave fields inside the port for different incident wave directions, water levels and return periods are simulated, and then two kinds of parameters are calculated to evaluate the wave conditions for the two layouts. Analyses show that Layout I is better than Layout II. Calculation results also show that the harbor will be calm for different wave directions under the design water level. On the contrary, the wave conditions do not wholly meet the requirements of a yacht port for ship berthing under the extreme water level. For safety consideration, the elevation of the breakwater might need to be properly increased to prevent wave overtopping under such water level. The extended numerical simulation model may provide an effective approach to computing wave heights in a harbor. 展开更多
关键词 random wave diffraction energy balance equation numerical simulation yacht port
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High-Accuracy NLOS Identification Based on Random Forest and High-Precision Positioning on 60 GHz Millimeter Wave 被引量:2
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作者 Qiuna Niu Wei Shi +1 位作者 Yongdao Xu Weijun Wen 《China Communications》 SCIE CSCD 2023年第12期96-110,共15页
60 GHz millimeter wave(mmWave)system provides extremely high time resolution and multipath components(MPC)separation and has great potential to achieve high precision in the indoor positioning.However,the ranging data... 60 GHz millimeter wave(mmWave)system provides extremely high time resolution and multipath components(MPC)separation and has great potential to achieve high precision in the indoor positioning.However,the ranging data is often contaminated by non-line-of-sight(NLOS)transmission.First,six features of 60GHz mm Wave signal under LOS and NLOS conditions are evaluated.Next,a classifier constructed by random forest(RF)algorithm is used to identify line-of-sight(LOS)or NLOS channel.The identification mechanism has excellent generalization performance and the classification accuracy is over 97%.Finally,based on the identification results,a residual weighted least squares positioning method is proposed.All ranging information including that under NLOS channels is fully utilized,positioning failure caused by insufficient LOS links can be avoided.Compared with the conventional least squares approach,the positioning error of the proposed algorithm is reduced by 49%. 展开更多
关键词 60 GHz millimeter wave indoor positioning NLOS identification random forest
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The New Form of Time-Dependent Mild Slope Equation for Random Waves 被引量:21
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作者 Zhang Yonggang , Li Yucheng Teng Bin Doctor Degree Candidate, The National Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116023Professor, The National,Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116023Associate Professor, The National Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116023 《China Ocean Engineering》 SCIE EI 1995年第4期387-394,共8页
The mild-slope equation derived by Berkhoff (1972), has widely been used in the numerical calculation of refraction and diffraction of regular waves. However, it is well known that the random sea waves has a significa... The mild-slope equation derived by Berkhoff (1972), has widely been used in the numerical calculation of refraction and diffraction of regular waves. However, it is well known that the random sea waves has a significant effect in the refraction and diffraction problems. In this paper, a new form of time-dependent mild slope equation for irregular waves was derived with Fade approximation and Kubo's time series concept. The equation was simplified using WKB method, and simple and practical irregular mild slope equation was obtained. Results of numerical calculations are compared with those of laboratory experiments. 展开更多
关键词 random wave mild slope equation Fade approximation WKB method simulation
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Efficient Simulation of Freak Waves in Random Oceanic Sea States 被引量:4
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作者 张运秋 胡金鹏 张宁川 《China Ocean Engineering》 SCIE EI 2009年第1期157-165,共9页
Numerical simulations of freak wave generation are studied in random oceanic sea states described by JONSWAP spectrum. The evolution of initial random wave trains is namerically carried out within the framework of the... Numerical simulations of freak wave generation are studied in random oceanic sea states described by JONSWAP spectrum. The evolution of initial random wave trains is namerically carried out within the framework of the modified fourorder nonlinear Schroedinger equation (mNLSE), and some involved influence factors are also discussed. Results show that if the sideband instability is satisfied, a random wave train may evolve into a freak wave train, and simultaneously the setting of the Phillips paranleter and enhancement coefficient of JONSWAP spectrum and initial random phases is very important for the formation of freak waves. The way to increase the generation efficiency of freak waves thsough changing the involved parameters is also presented. 展开更多
关键词 freak waves mNLSE sideband instability random wave JONSWAP spectrum
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Experimental study of freak waves due to three-dimensional island terrain in random wave 被引量:2
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作者 Li Zou Aimin Wang +2 位作者 Zhen Wang Yuguo Pei Xiaolong Liu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第6期92-99,共8页
An experimental study is carried out for waves passing an isolated reef terrain in a wave tank. A three-dimensional model of a representative and isolated reef terrain in the West Pacific is built. Random wave trains ... An experimental study is carried out for waves passing an isolated reef terrain in a wave tank. A three-dimensional model of a representative and isolated reef terrain in the West Pacific is built. Random wave trains with various periods and wave heights are generated by a wave maker using the improved JONSWAP spectrum. It is observed that there are different kinds of generation processes and waveforms of freak waves. The freak wave factor Hm/Hs (where Hm is the maximum wave height of wave series, and Hs is significant wave height) is analyzed in detail, in terms of the skewness, kurtosis and water depth, as well as the relationship between freak wave height H& and skewness. The freak wave factor Hm/Hs is found to be in positive correlation with the kurtosis, while larger H[x tends to be related with bigger skewness. The rapid variation of water depth, such as slope and seamount, contributes to the occurrence probability of freak waves. 展开更多
关键词 freak waves random wave SKEWNESS and KURTOSIS THREE-DIMENSIONAL ISLAND TERRAIN
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Second-order random wave solutions for interfacial internal waves in N-layer density-stratified fluid 被引量:3
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作者 陈小刚 宋金宝 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第4期756-766,共11页
This paper studies the random internal wave equations describing the density interface displacements and the velocity potentials of N-layer stratified fluid contained between two rigid walls at the top and bottom. The... This paper studies the random internal wave equations describing the density interface displacements and the velocity potentials of N-layer stratified fluid contained between two rigid walls at the top and bottom. The density interface displacements and the velocity potentials were solved to the second-order by an expansion approach used by Longuet-Higgins (1963) and Dean (1979) in the study of random surface waves and by Song (2004) in the study of second- order random wave solutions for internal waves in a two-layer fluid. The obtained results indicate that the first-order solutions are a linear superposition of many wave components with different amplitudes, wave numbers and frequencies, and that the amplitudes of first-order wave components with the same wave numbers and frequencies between the adjacent density interfaces are modulated by each other. They also show that the second-order solutions consist of two parts: the first one is the first-order solutions, and the second one is the solutions of the second-order asymptotic equations, which describe the second-order nonlinear modification and the second-order wave-wave interactions not only among the wave components on same density interfaces but also among the wave components between the adjacent density interfaces. Both the first-order and second-order solutions depend on the density and depth of each layer. It is also deduced that the results of the present work include those derived by Song (2004) for second-order random wave solutions for internal waves in a two-layer fluid as a particular case. 展开更多
关键词 N-layer density-stratified fluid interracial internal waves second-order random wave solutions
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Second-Order Solutions for Random Interfacial Waves Under Steady Uniform Currents 被引量:3
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作者 宋金宝 《China Ocean Engineering》 SCIE EI 2005年第2期333-338,共6页
In the present research, the study of Song (2004) for random interfacial waves in two-layer fluid is extended to the case of fluids moving at different steady uniform speeds. The equations describing the random displa... In the present research, the study of Song (2004) for random interfacial waves in two-layer fluid is extended to the case of fluids moving at different steady uniform speeds. The equations describing the random displacements of the density interface and the associated velocity potentials in two-layer fluid are solved to the second order, and the wave-wave interactions of the wave components and the interactions between the waves and currents are described. As expected, the extended solutions include those obtained by Song (2004) as one special case where the steady uniform currents of the two fluids are taken as zero, and the solutions reduce to those derived by Sharma and Dean (1979) for random surface waves if the density of the upper fluid and the current of the lower fluid are both taken as zero. 展开更多
关键词 two-layer fluid uniform current random interfacial waves second-order solutions
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Theoretical Model and Random Simulation for Nonlinear Interaction of Irregular Waves with Vertical Wall 被引量:3
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作者 Hong, Guangwen Feng, Weibing 《China Ocean Engineering》 SCIE EI 1993年第3期263-288,共26页
According to the theoretical solutions for the nonlinear three-dimensional gravity surface waves and their interactions with vertical wall previously proposed by the lead author, in this paper an exact second-order ra... According to the theoretical solutions for the nonlinear three-dimensional gravity surface waves and their interactions with vertical wall previously proposed by the lead author, in this paper an exact second-order random model of the unified wave motion process for nonlinear irregular waves and their interactions with vertical wall in uniform current is formulated, the corresponding theoretical nonlinear spectrum is derived, and the digital simulation model suitable to the use of the FFT (Fast Fourier Transform) algorithm is also given. Simulations of wave surface, wave pressure, total wave pressure and its moment are performed. The probability properties and statistical characteristics of these realizations are tested, which include the verifications of normality for linear process and of non-normality for nonlinear process; the consistencies of the theoretical spectra with simulated ones; the probability properties of apparent characteristics, such as amplitudes, periods, and extremes (maximum and minimum, positive and negative extremes). The statistical analysis and comparisons demonstrate that the proposed theoretical and computing models are realistic and effective, and estimated spectra are in good agreement with the theoretical ones, and the probability properties of the simulated waves are similar to those of the sea waves. At the same time, the simulating computation can be completed rapidly and easily. 展开更多
关键词 ALGORITHMS Coastal engineering Fast Fourier transforms Mathematical models PROBABILITY random processes Retaining walls Surface waves
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Hyperbolic Mild Slope Equations with Inclusion of Amplitude Dispersion Effect:Random Waves 被引量:2
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作者 邹志利 金红 《China Ocean Engineering》 SCIE EI 2008年第4期595-610,共16页
New hyperbolic mild slope equations for random waves are developed with the inclusion of amplitude dispersion. The frequency perturbation around the peak frequency of random waves is adopted to extend the equations fo... New hyperbolic mild slope equations for random waves are developed with the inclusion of amplitude dispersion. The frequency perturbation around the peak frequency of random waves is adopted to extend the equations for regular waves to random waves. The nonlinear effect of amplitude dispersion is incorporated approximately into the model by only considering the nonlinear effect on the carrier waves of random waves, which is done by introducing a representative wave amplitude for the carrier waves. The computation time is gready saved by the introduction of the representative wave amplitude. The extension of the present model to breaking waves is also considered in order to apply the new equations to surf zone. The model is validated for random waves propagate over a shoal and in surf zone against measurements. 展开更多
关键词 mild slope equations hyperbolic model random waves nonlinear wave
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Observations of Freak Waves in Random Wave Field in 2D Experimental Wave Flume 被引量:2
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作者 李金宣 李鹏飞 柳淑学 《China Ocean Engineering》 SCIE EI CSCD 2013年第5期659-670,共12页
Long time series of wave field are experimentally simulated by JONSWAP spectra with random phases in a 2D wave flume. Statistic properties of wave surface, such as significant wave height, skewness and kurtosis, are a... Long time series of wave field are experimentally simulated by JONSWAP spectra with random phases in a 2D wave flume. Statistic properties of wave surface, such as significant wave height, skewness and kurtosis, are analyzed, and the freak wave occurrence probability and its relations with Benjamin-Feir index (BFI) are also investigated. The results show that the skewness and the kurtosis are significantly dependent on the wave steepness, and the kurtosis increases along the flume when BFI is large. The freak waves are observed in random wave groups. They occur more frequently than expected, especially for the wave groups with large BFI. 展开更多
关键词 freak waves Benjamin-Feir instability random wave groups
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Numerical Study of A Round Buoyant Jet Under the Effect of JONSWAP Random Waves 被引量:2
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作者 陈永平 李志伟 +1 位作者 张长宽 徐振山 《China Ocean Engineering》 SCIE EI 2012年第2期235-250,共16页
This paper presents a numerical study on the hydrodynamic behaviours of a round buoyant jet under the effect of JONSWAP random waves. A three-dimensional large eddy simulation (LES) model is developed to simulate th... This paper presents a numerical study on the hydrodynamic behaviours of a round buoyant jet under the effect of JONSWAP random waves. A three-dimensional large eddy simulation (LES) model is developed to simulate the buoyant jet in a stagnant ambient and JONSWAP random waves. By comparison of velocity and concentration fields, it is found that the buoyant jet exhibits faster decay of centerline velocity, wider lateral spreading and larger initial dilution under the wave effect, indicating that wave dynamics improves the jet entrainment and mixing in the near field, and subsequently mitigate the jet impacts in the far field. The effect of buoyancy force on the jet behaviours in the random waves is also numerically investigated. The results show that the wave effect on the jet entrainment and mixing is considerably weakened under the existence of buoyancy force, resulting in a slower decay rate of centerline velocity and a narrower jet width for the jet with initial buoyancy. 展开更多
关键词 numerical study large eddy simulation buoyant jet JONSWAP random waves
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Enhancing the resolution of sparse rock property measurements using machine learning and random field theory 被引量:1
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作者 Jiawei Xie Jinsong Huang +3 位作者 Fuxiang Zhang Jixiang He Kaifeng Kang Yunqiang Sun 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期3924-3936,共13页
The travel time of rock compressional waves is an essential parameter used for estimating important rock properties,such as porosity,permeability,and lithology.Current methods,like wireline logging tests,provide broad... The travel time of rock compressional waves is an essential parameter used for estimating important rock properties,such as porosity,permeability,and lithology.Current methods,like wireline logging tests,provide broad measurements but lack finer resolution.Laboratory-based rock core measurements offer higher resolution but are resource-intensive.Conventionally,wireline logging and rock core measurements have been used independently.This study introduces a novel approach that integrates both data sources.The method leverages the detailed features from limited core data to enhance the resolution of wireline logging data.By combining machine learning with random field theory,the method allows for probabilistic predictions in regions with sparse data sampling.In this framework,12 parameters from wireline tests are used to predict trends in rock core data.The residuals are modeled using random field theory.The outcomes are high-resolution predictions that combine both the predicted trend and the probabilistic realizations of the residual.By utilizing unconditional and conditional random field theories,this method enables unconditional and conditional simulations of the underlying high-resolution rock compressional wave travel time profile and provides uncertainty estimates.This integrated approach optimizes the use of existing core and logging data.Its applicability is confirmed in an oil project in West China. 展开更多
关键词 Wireline logs Core characterization Compressional wave travel time Machine learning random field theory
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Dynamic Response of Sea-Crossing Rail-cum-Road Cable-Stayed Bridge Influenced by Random Wind–Wave–Undercurrent Coupling
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作者 BIAN Chen-jie DU Li-ming +2 位作者 WANG Ga-ping LI Xin LI Wei-ran 《China Ocean Engineering》 SCIE EI CSCD 2023年第1期85-100,共16页
Sea-crossing bridges are affected by random wind–wave–undercurrent coupling loads, due to the complex marine environment. The dynamic response of long-span Rail-cum-Road cable-stayed bridges is particularly severe u... Sea-crossing bridges are affected by random wind–wave–undercurrent coupling loads, due to the complex marine environment. The dynamic response of long-span Rail-cum-Road cable-stayed bridges is particularly severe under their influence, potentially leading to safety problems. In this paper, a fluid–structure separation solution method is implemented using Ansys–Midas co-simulation, in order to solve the above issues effectively while using less computational resources. The feasibility of the method is verified by comparing the tower top displacement response with relevant experimental data. From time and frequency domain perspectives, the displacement and acceleration responses of the sea-crossing Rail-cum-Road cable-stayed bridge influenced by wave-only, wind–wave, and wind–wave–undercurrent coupling are comparatively studied. The results indicate that the displacement and acceleration of the front bearing platform top are more significant than those of the rear bearing platform. The dominant frequency under wind–wave–undercurrent coupling is close to the natural vibration frequencies of several bridge modes,such that wind–wave–undercurrent coupling is more likely to cause a resonance effect in the bridge. Compared with the wave-only and wind–wave coupling, wind–wave–undercurrent coupling can excite bridges to produce larger displacement and acceleration responses: at the middle of the main girder span, compared with the wave-only case, the maximum displacement in the transverse bridge direction increases by 23.58% and 46.95% in the wind–wave and wind–wave–undercurrent coupling cases, respectively;at the tower top, the variation in the amplitude of the displacement and acceleration responses of wind–wave and wind–wave–undercurrent coupling are larger than those in the wave-only case, where the acceleration change amplitude of the tower top is from-0.93 to 0.86 m/s^(2) in the waveonly case, from-2.2 to 2.1 m/s^(2) under wind–wave coupling effect, and from-2.6 to 2.65 m/s^(2) under wind–wave–undercurrent coupling effect, indicating that the tower top is mainly affected by wind loads, but wave and undercurrent loads cannot be neglected. 展开更多
关键词 random wind wave undercurrent coupling effect Rail-cum-Road cable-stayed bridge dynamic response
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The dispersion of surface contaminants by Stokes drift in random waves 被引量:1
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作者 HUANG Guoxing LAW Wing-Keung Adrian 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2018年第7期55-61,共7页
Contaminants that are floating on the surface of the ocean are subjected to the action of random waves.In the literature,it has been asserted by researchers that the random wave action will lead to a dispersion mechan... Contaminants that are floating on the surface of the ocean are subjected to the action of random waves.In the literature,it has been asserted by researchers that the random wave action will lead to a dispersion mechanism through the induced Stokes drift,and that this dispersion mechanism may have the same order of significance comparable with the others means due to tidal currents and wind.It is investigated whether or not surface floating substances will disperse in the random wave environment due to the induced Stokes drift.An analytical derivation is first performed to obtain the drift velocity under the random waves.From the analysis,it is shown that the drift velocity is a time-independent value that does not possess any fluctuation given a specific wave energy spectrum.Thus,the random wave drift by itself should not have a dispersive effect on the surface floating substances.Experiments were then conducted with small floating objects subjected to P-M spectral waves in a laboratory wave flume,and the experimental results reinforced the conclusion drawn. 展开更多
关键词 DISPERSION surface contaminants random wave Stokes drift
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Hydrodynamic Analysis of Elastic Floating Collars in Random Waves 被引量:5
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作者 白晓东 赵云鹏 +1 位作者 董国海 李玉成 《China Ocean Engineering》 SCIE EI CSCD 2015年第3期341-356,共16页
As the main load-bearing component of fish cages, the floating collar supports the whole cage and undergoes large deformations. In this paper, a mathematical method is developed to study the motions and elastic deform... As the main load-bearing component of fish cages, the floating collar supports the whole cage and undergoes large deformations. In this paper, a mathematical method is developed to study the motions and elastic deformations of elastic floating collars in random waves. The irregular wave is simulated by the random phase method and the statistical approach and Fourier transfer are applied to analyze the elastic response in both time and frequency domains. The governing equations of motions are established by Newton's second law, and the governing equations of deformations are obtained based on curved beam theory and modal superposition method. In order to validate the numerical model of the floating collar attacked by random waves, a series of physical model tests are conducted. Good relationship between numerical simulation and experimental observations is obtained. The numerical results indicate that the transfer function of out-of-plane and in-plane deformations increase with the increasing of wave frequency. In the frequency range between 0.6 Hz and 1.1 Hz, a linear relationship exists between the wave elevations and the deformations. The average phase difference between the wave elevation and out-of-plane deformation is 60° with waves leading and the phase between the wave elevation and in-plane deformation is 10° with waves lagging. In addition, the effect of fish net on the elastic response is analyzed. The results suggest that the deformation of the floating collar with fish net is a little larger than that without net. 展开更多
关键词 floating collars random waves hydrodynamic characteristics in-plane and out-of-plane deformation net effect
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Coupling Response of Heave and Moonpool Water Motion of A Truss Spar Platform in Random Waves 被引量:4
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作者 刘利琴 周晗 唐友刚 《China Ocean Engineering》 SCIE EI CSCD 2015年第2期169-182,共14页
This paper presents the heave responses and the moonpool water motions of a truss Spar platform with semi-closed moonpool in random waves. A 2-DOF(degree of freedom) coupling dynamical equations of the platform heav... This paper presents the heave responses and the moonpool water motions of a truss Spar platform with semi-closed moonpool in random waves. A 2-DOF(degree of freedom) coupling dynamical equations of the platform heave and vertical motions of the moonpool water are derived. The linear wave theory is used to simulate the random waves. The response statistical values and the power spectrums are calculated to analyze the mutual influences between the platform heave and the moonpool water motions for different opening ratios of the moonpool. The effect of coupling parameters on the platform heave and the moonpool water motions are analyzed. The results show that motions of the moonpool water significantly affected the platform heave when the characteristic wave period is far away from the natural period of the platform heave, and different moonpool opening ratios lead to different heave amplitudes of the platform. In the actual design, an optimized moonpool opening ratio can be designed to reduce heave motions of the platform. 展开更多
关键词 truss Spar platform heave moonpool water coupling random waves power spectrum
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