Pub Date : 2012-06-01DOI: 10.1260/1759-3131.3.2.109
S. Karimi, J. Shiri, O. Kisi, Oleg Makarynskyy
Forecasting lake level at various prediction intervals is an essential issue in such industrial applications as navigation, water resource planning and catchment management. In the present study, two data driven techniques, namely Gene Expression Programming and Adaptive Neuro-Fuzzy Inference System, were applied for predicting daily lake levels for three prediction intervals. Daily water-level data from Urmieh Lake in Northwestern Iran were used to train, test and validate the used techniques. Three statistical indexes, coefficient of determination, root mean square error and variance accounted for were used to assess the performance of the used techniques. Technique inter-comparisons demonstrated that the GEP surpassed the ANFIS model at each of the prediction intervals. A traditional auto regressive moving average model was also applied to the same data sets; the obtained results were compared with those of the data driven approaches demonstrating superiority of the data driven models to ARMA.
{"title":"Forecasting Water Level Fluctuations of Urmieh Lake Using Gene Expression Programming and Adaptive Neuro-Fuzzy Inference System","authors":"S. Karimi, J. Shiri, O. Kisi, Oleg Makarynskyy","doi":"10.1260/1759-3131.3.2.109","DOIUrl":"https://doi.org/10.1260/1759-3131.3.2.109","url":null,"abstract":"Forecasting lake level at various prediction intervals is an essential issue in such industrial applications as navigation, water resource planning and catchment management. In the present study, two data driven techniques, namely Gene Expression Programming and Adaptive Neuro-Fuzzy Inference System, were applied for predicting daily lake levels for three prediction intervals. Daily water-level data from Urmieh Lake in Northwestern Iran were used to train, test and validate the used techniques. Three statistical indexes, coefficient of determination, root mean square error and variance accounted for were used to assess the performance of the used techniques. Technique inter-comparisons demonstrated that the GEP surpassed the ANFIS model at each of the prediction intervals. A traditional auto regressive moving average model was also applied to the same data sets; the obtained results were compared with those of the data driven approaches demonstrating superiority of the data driven models to ARMA.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121650356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-01DOI: 10.1260/1759-3131.3.2.127
S. Prakash, C. Mahesh, R. Gairola
The sea level anomalies (SLA) in the tropical Indian Ocean (TIO) during two consecutive contrasting southwest monsoon years of 2002 (deficit) and 2003 (normal) are examined using multi-satellite measurements. The rainfall anomalies over the TIO in the month of July show distinct patterns during these two years. The more consistent patterns analogous to rainfall anomalies are reflected in the freshwater flux anomalies which is one of the major contributors of the local sea level change. As a result, the SLA shows distinct features in the north Indian Ocean during these two years. The surface atmospheric convergence and divergence patterns in the TIO are also investigated using multi-satellite wind vectors which are supposed to be correlated with the southwest monsoon rainfall and a key component of sea level change. The results suggest that the eustatic effect and near surface convergence/divergence of winds have significant impact on SLA locally.
{"title":"Sea Level Anomalies in the Tropical Indian Ocean during Two Contrasting Southwest Monsoon Years","authors":"S. Prakash, C. Mahesh, R. Gairola","doi":"10.1260/1759-3131.3.2.127","DOIUrl":"https://doi.org/10.1260/1759-3131.3.2.127","url":null,"abstract":"The sea level anomalies (SLA) in the tropical Indian Ocean (TIO) during two consecutive contrasting southwest monsoon years of 2002 (deficit) and 2003 (normal) are examined using multi-satellite measurements. The rainfall anomalies over the TIO in the month of July show distinct patterns during these two years. The more consistent patterns analogous to rainfall anomalies are reflected in the freshwater flux anomalies which is one of the major contributors of the local sea level change. As a result, the SLA shows distinct features in the north Indian Ocean during these two years. The surface atmospheric convergence and divergence patterns in the TIO are also investigated using multi-satellite wind vectors which are supposed to be correlated with the southwest monsoon rainfall and a key component of sea level change. The results suggest that the eustatic effect and near surface convergence/divergence of winds have significant impact on SLA locally.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122615673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-01DOI: 10.1260/1759-3131.3.2.85
Takahiro Kumagai, Sayaka Nakajima
Beneficial use of shell for constitutive materials of beach or tidal flat is proposed instead of its disposal. Since the shape of shell fragment is oblate, the knowledge on littoral drift of sand with spherical shape could not be applied directly for understanding of its behavior under waves. In this study, critical shields number and settling velocity of shell fragment are evaluated changing oblate shapes of the fragments, and the characteristics of bed load transport of shell and shell-mixed sand beds are examined by a movable-bed experiment. From the experiments, the effects of oblateness on the increase of resistance to wave and current are elucidated. It is found that the interaction of sand and shell on their movements has an effect on the bed-load rate changing the height of sand ripples.
{"title":"Experimental Study on Bed Load Transport of Shell Fragment-Mixed Sand under Waves","authors":"Takahiro Kumagai, Sayaka Nakajima","doi":"10.1260/1759-3131.3.2.85","DOIUrl":"https://doi.org/10.1260/1759-3131.3.2.85","url":null,"abstract":"Beneficial use of shell for constitutive materials of beach or tidal flat is proposed instead of its disposal. Since the shape of shell fragment is oblate, the knowledge on littoral drift of sand with spherical shape could not be applied directly for understanding of its behavior under waves. In this study, critical shields number and settling velocity of shell fragment are evaluated changing oblate shapes of the fragments, and the characteristics of bed load transport of shell and shell-mixed sand beds are examined by a movable-bed experiment. From the experiments, the effects of oblateness on the increase of resistance to wave and current are elucidated. It is found that the interaction of sand and shell on their movements has an effect on the bed-load rate changing the height of sand ripples.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133804195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-01DOI: 10.1260/1759-3131.3.1.71
V. S. Kumar, G. Dora, C. Philip, P. Pednekar, J. Singh
Measured current data at 7 locations and tide data at 3 locations during the pre-summer monsoon period along the west coast of India is used in the study. The surface currents during March showed a predominant northward trend and during April it was towards south. Estimated tidal currents were upto 25 cm s−1 with an average value of 8 cm s−1. Current tidal form number varied from 0.56 to 1 at different locations indicating currents are mixed. M2 and S2 tidal current constituents rotated clock wise at all location. Near surface, the alongshore current was 2.6 to 5.9% of the alongshore wind and near bottom it was 1.9 to 3.6% of the alongshore wind.
研究使用了印度西海岸夏前风期7个地点的实测海流资料和3个地点的潮汐资料。3月表层流以北流为主，4月表层流以南流为主。估计的潮流高达25 cm s - 1，平均值为8 cm s - 1。不同地点的潮流潮形数由0.56至1不等，显示水流混合。M2和S2潮流成分在所有位置沿时钟方向旋转。近岸流为近岸风的2.6 ~ 5.9%，近岸流为近岸风的1.9 ~ 3.6%。
{"title":"Nearshore Currents along the Karnataka Coast, West Coast of India","authors":"V. S. Kumar, G. Dora, C. Philip, P. Pednekar, J. Singh","doi":"10.1260/1759-3131.3.1.71","DOIUrl":"https://doi.org/10.1260/1759-3131.3.1.71","url":null,"abstract":"Measured current data at 7 locations and tide data at 3 locations during the pre-summer monsoon period along the west coast of India is used in the study. The surface currents during March showed a predominant northward trend and during April it was towards south. Estimated tidal currents were upto 25 cm s−1 with an average value of 8 cm s−1. Current tidal form number varied from 0.56 to 1 at different locations indicating currents are mixed. M2 and S2 tidal current constituents rotated clock wise at all location. Near surface, the alongshore current was 2.6 to 5.9% of the alongshore wind and near bottom it was 1.9 to 3.6% of the alongshore wind.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130333256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-01DOI: 10.1260/1759-3131.3.1.57
S. Chandrasekaran, Harender
Ocean wave energy plays a significant role in meeting the growing demand of electric power. Economic, environmental, and technical advantages of wave energy set it apart from other renewable energy resources. Present study describes a newly proposed Mechanical Wave Energy Converter (MEWC) that is employed to harness heave motion of floating buoy to generate power. Focus is on the conceptual development of the device, illustrating details of component level analysis. Employed methodology has many advantages such as i) simple and easy fabrication; ii) easy to control the operations during rough weather; and iii) low failure rate during normal sea conditions. Experimental investigations carried out on the scaled model of MWEC show better performance and its capability to generate power at higher efficiency in regular wave fields. Design Failure Mode and Effect Analysis (FMEA) shows rare failure rates for all components except the floating buoy.
{"title":"Power Generation Using Mechanical Wave Energy Converter","authors":"S. Chandrasekaran, Harender","doi":"10.1260/1759-3131.3.1.57","DOIUrl":"https://doi.org/10.1260/1759-3131.3.1.57","url":null,"abstract":"Ocean wave energy plays a significant role in meeting the growing demand of electric power. Economic, environmental, and technical advantages of wave energy set it apart from other renewable energy resources. Present study describes a newly proposed Mechanical Wave Energy Converter (MEWC) that is employed to harness heave motion of floating buoy to generate power. Focus is on the conceptual development of the device, illustrating details of component level analysis. Employed methodology has many advantages such as i) simple and easy fabrication; ii) easy to control the operations during rough weather; and iii) low failure rate during normal sea conditions. Experimental investigations carried out on the scaled model of MWEC show better performance and its capability to generate power at higher efficiency in regular wave fields. Design Failure Mode and Effect Analysis (FMEA) shows rare failure rates for all components except the floating buoy.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116023789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research seeks to test the hypothesis that natural gamma radiation (NGR) from Ocean Drilling Program Site 1094, which displays variability over the last glacial-interglacial cycle similar to dust in the Vostok ice core, reflects fine-grained terrigenous sediment delivered by eolian processes. Grain size was measured on 400 samples spanning 0–20 m in a composite core. Accumulation of the <63μ size fraction at Site 1094 and dust in Vostok exhibit a negative correlation, suggesting the fine sediments are not dominantly eolian. However the technique used for grain size measurements cannot distinguish between terrigenous and biogenous materials; therefore it is possible much fine-grained material is diatoms. An inverse correlation between fine sediments and NGR supports this interpretation, and implies terrigenous materials were at times diluted by microfossils from high biological productivity. Fine marine sediments correlate positively with temperature and negatively with marine aerosol Na+ in Vostok. One plausible explanation is extensive sea-ice of cold intervals steepened ocean-continent temperature gradients, intensified winds, and led to increased transport of dust and marine aerosol to Antarctica yet also reduced biological productivity at Site 1094. Such a reduction despite increases in NGR, potentially representing Fe-rich dust influx, would require light limitation or stratification associated with sea-ice.
{"title":"Inverse Relationship of Marine Aerosol and Dust in Antarctic Ice with Fine-Grained Sediment in the South Atlantic Ocean: Implications for Sea-Ice Coverage and Wind Strength","authors":"Sharon L. Kanfoush","doi":"10.1260/1759-3131.3.1.1","DOIUrl":"https://doi.org/10.1260/1759-3131.3.1.1","url":null,"abstract":"This research seeks to test the hypothesis that natural gamma radiation (NGR) from Ocean Drilling Program Site 1094, which displays variability over the last glacial-interglacial cycle similar to dust in the Vostok ice core, reflects fine-grained terrigenous sediment delivered by eolian processes. Grain size was measured on 400 samples spanning 0–20 m in a composite core. Accumulation of the <63μ size fraction at Site 1094 and dust in Vostok exhibit a negative correlation, suggesting the fine sediments are not dominantly eolian. However the technique used for grain size measurements cannot distinguish between terrigenous and biogenous materials; therefore it is possible much fine-grained material is diatoms. An inverse correlation between fine sediments and NGR supports this interpretation, and implies terrigenous materials were at times diluted by microfossils from high biological productivity. Fine marine sediments correlate positively with temperature and negatively with marine aerosol Na+ in Vostok. One plausible explanation is extensive sea-ice of cold intervals steepened ocean-continent temperature gradients, intensified winds, and led to increased transport of dust and marine aerosol to Antarctica yet also reduced biological productivity at Site 1094. Such a reduction despite increases in NGR, potentially representing Fe-rich dust influx, would require light limitation or stratification associated with sea-ice.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131601754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-01DOI: 10.1260/1759-3131.3.1.17
G. Auad, P. Martos
A high-resolution ocean model and hydrographic observations are used to characterize the shelf circulation of the northern Argentinean shelf during the study period (1993–2008) and ultimately to explore possible linkages among atmospheric, oceanic, and biological climatic variability. Abundance of larvae and eggs of the local anchovy species, Engraulis anchoita, exhibit a spatial and temporal variability similar to those stocks found in other parts of the world and that we interpret in the context of the particularities of the local circulation and hydrography. Two (statistically) coupled modes of wind stress-surface velocity are described and interpreted in terms of historical and new information. A complex picture emerges in which the intensity of both a thermal shelf front, the alongshore flow, and larvae abundance would be connected and forced by local wind stresses. For all areas examined on the shelf, the larvae/egg abundance would not be very sensitive to short-lived climatic fluctuations (e.g., year-to-year) but they would be indeed to regime shifts. The shallow shelf area bounded by the 39°S and 41°S parallels would expose a clearer linkage between physical and biological variables than that north of 39°S. We attribute this fact to the particular physical conditions found in the southernmost area, which would favor an increased habitat quality for Engraulis anchoita.
{"title":"Climate Variability of the Northern Argentinean Shelf Circulation: Impact on Engraulis Anchoita","authors":"G. Auad, P. Martos","doi":"10.1260/1759-3131.3.1.17","DOIUrl":"https://doi.org/10.1260/1759-3131.3.1.17","url":null,"abstract":"A high-resolution ocean model and hydrographic observations are used to characterize the shelf circulation of the northern Argentinean shelf during the study period (1993–2008) and ultimately to explore possible linkages among atmospheric, oceanic, and biological climatic variability. Abundance of larvae and eggs of the local anchovy species, Engraulis anchoita, exhibit a spatial and temporal variability similar to those stocks found in other parts of the world and that we interpret in the context of the particularities of the local circulation and hydrography. Two (statistically) coupled modes of wind stress-surface velocity are described and interpreted in terms of historical and new information. A complex picture emerges in which the intensity of both a thermal shelf front, the alongshore flow, and larvae abundance would be connected and forced by local wind stresses. For all areas examined on the shelf, the larvae/egg abundance would not be very sensitive to short-lived climatic fluctuations (e.g., year-to-year) but they would be indeed to regime shifts. The shallow shelf area bounded by the 39°S and 41°S parallels would expose a clearer linkage between physical and biological variables than that north of 39°S. We attribute this fact to the particular physical conditions found in the southernmost area, which would favor an increased habitat quality for Engraulis anchoita.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124907594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-03-01DOI: 10.1260/1759-3131.3.1.45
R. Balaji
A curtailed numerical model has been developed to assess the tidal hydrodynamics of entrance of a navigational channel in Abu Dhabi coast, United Arab Emirates. The curtailed model is developed using a finite element based numerical scheme, RMA2 (Donnell et al., 2006). The boundary conditions for the model were extracted from a large scale numerical model covering entire Abu Dhabi coast, developed using TELEMAC (Hervouet, 2000) modeling software. The hydrodynamic results of the curtailed model are validated with that of large scale model. The comparisons of water levels and current velocities obtained from the two models are found to be in agreement, demonstrating the efficiency and accuracy of the curtailed numerical model. The features of the tidal current pattern in the vicinity of the entrance of the navigational channel are also discussed. The details of the numerical scheme, model setup and methodology are presented and discussed in this paper.
{"title":"A Case Study on Curtailed Tidal Hydrodynamic Modeling along UAE Coast","authors":"R. Balaji","doi":"10.1260/1759-3131.3.1.45","DOIUrl":"https://doi.org/10.1260/1759-3131.3.1.45","url":null,"abstract":"A curtailed numerical model has been developed to assess the tidal hydrodynamics of entrance of a navigational channel in Abu Dhabi coast, United Arab Emirates. The curtailed model is developed using a finite element based numerical scheme, RMA2 (Donnell et al., 2006). The boundary conditions for the model were extracted from a large scale numerical model covering entire Abu Dhabi coast, developed using TELEMAC (Hervouet, 2000) modeling software. The hydrodynamic results of the curtailed model are validated with that of large scale model. The comparisons of water levels and current velocities obtained from the two models are found to be in agreement, demonstrating the efficiency and accuracy of the curtailed numerical model. The features of the tidal current pattern in the vicinity of the entrance of the navigational channel are also discussed. The details of the numerical scheme, model setup and methodology are presented and discussed in this paper.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116804882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-02-20DOI: 10.1260/1759-3131.3.3.163
T. Duong, R. Ranasinghe, A. Luijendijk, H. Ngo, D. Roelvink
Tidal inlets are of great societal importance as they are often associated with ports and harbours, industry, tourism, recreation and prime waterfront real estate. Their behaviour is governed by the delicate balance of oceanic processes (tides, waves and mean sea level), and fluvial/estuarine processes (riverflow and heat fluxes), all of which can be significantly affected by climate change (CC) processes. This study investigates the potential range of CC impacts on the stability (closed/open state and locational stability) via the application of a sophisticated process based morphodynamic model (Delft3D) to strategically selected schematized inlet morphologies and forcing conditions. Results show that, under worst case scenario conditions, the integrated effect of climate change driven increase in mean sea level, wave height and wave angle may significantly change inlet stability condition.
{"title":"Climate Change Impacts on the Stability of Small Tidal Inlets: A Numerical Modelling Study Using the Realistic Analogue Approach","authors":"T. Duong, R. Ranasinghe, A. Luijendijk, H. Ngo, D. Roelvink","doi":"10.1260/1759-3131.3.3.163","DOIUrl":"https://doi.org/10.1260/1759-3131.3.3.163","url":null,"abstract":"Tidal inlets are of great societal importance as they are often associated with ports and harbours, industry, tourism, recreation and prime waterfront real estate. Their behaviour is governed by the delicate balance of oceanic processes (tides, waves and mean sea level), and fluvial/estuarine processes (riverflow and heat fluxes), all of which can be significantly affected by climate change (CC) processes. This study investigates the potential range of CC impacts on the stability (closed/open state and locational stability) via the application of a sophisticated process based morphodynamic model (Delft3D) to strategically selected schematized inlet morphologies and forcing conditions. Results show that, under worst case scenario conditions, the integrated effect of climate change driven increase in mean sea level, wave height and wave angle may significantly change inlet stability condition.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128577523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-12-01DOI: 10.1260/1759-3131.2.4.303
A. C. Mayilvahanan, P. Selvam
Wind energy is a reliable source of sustainable power generation and has been an active area of research globally to economically harness the energy for human use. Reliable source of wind energy pushed the engineers to install wind turbines near and far off the coasts. In shallow water upto 100 m, fixed structures like tripods, jackets, monopiles and gravity base are functionally and economically feasible. In deep waters, a floating substructure can be more economical for offshore wind turbine. In this study a barge type floater of different aspect ratios from 0.4 to 1.0 is investigated for its performance under wave and wind loading. All these floaters were designed with a defined transverse metacentric height (GM) equal to 1.0 m and the hydrodynamic analysis is carried out using WAMIT. The barge with aspect ratio B/L = 1.0 is found to have lowest pitch RAO. The time domain surge, heave and pitch response for this barge has been obtained using Integro-differential equation of motion and the statistical response characteristics are compared for two different cases of excitation namely, wave excitation alone and combined wave and wind excitation. Statistics of surge, heave and pitch responses are obtained for three different seas states and for two different wave heading angles.
{"title":"Time Domain Response Analysis of Barge Floater Supporting an Offshore Wind Turbine","authors":"A. C. Mayilvahanan, P. Selvam","doi":"10.1260/1759-3131.2.4.303","DOIUrl":"https://doi.org/10.1260/1759-3131.2.4.303","url":null,"abstract":"Wind energy is a reliable source of sustainable power generation and has been an active area of research globally to economically harness the energy for human use. Reliable source of wind energy pushed the engineers to install wind turbines near and far off the coasts. In shallow water upto 100 m, fixed structures like tripods, jackets, monopiles and gravity base are functionally and economically feasible. In deep waters, a floating substructure can be more economical for offshore wind turbine. In this study a barge type floater of different aspect ratios from 0.4 to 1.0 is investigated for its performance under wave and wind loading. All these floaters were designed with a defined transverse metacentric height (GM) equal to 1.0 m and the hydrodynamic analysis is carried out using WAMIT. The barge with aspect ratio B/L = 1.0 is found to have lowest pitch RAO. The time domain surge, heave and pitch response for this barge has been obtained using Integro-differential equation of motion and the statistical response characteristics are compared for two different cases of excitation namely, wave excitation alone and combined wave and wind excitation. Statistics of surge, heave and pitch responses are obtained for three different seas states and for two different wave heading angles.","PeriodicalId":105024,"journal":{"name":"The International Journal of Ocean and Climate Systems","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131046996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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