Pub Date : 2023-02-22DOI: 10.1177/14750902231155677
Arunakumar Hunasanahally Sathyanarayana, P. Suvarna, Pruthviraj Umesh, K. G. Shirlal
Coastal erosion is a global concern that has been augmenting due to the natural evolution of beaches, human activities and sea-level rise. One of the eco-friendly shore protection methods is to dissipate the wave energy by constructing offshore breakwaters. Conical pile head breakwater (CPHB) is one of the eco-friendly innovative offshore structures consisting of closely spaced piles with an enlarged cross-sectional area (conical pile head) in the vicinity of the free surface. In the present study, perforations are incorporated over the conical pile head to achieve higher efficiency by promoting energy dissipation. The influence of the perforations on the performance characteristics, namely wave transmission (Kt), wave reflection (Kr) and energy dissipation (Kd) of the perforated CPHB is comprehensively investigated through physical model studies. The effect of perforations and their distribution around the pile head (Pa), percentage of perforation (P) and size of perforations (S/D) on the wave attenuation characteristics are evaluated to arrive at an optimum configuration. The study is carried out under monochromatic waves of varying wave height (0.06–0.16 m) and wave period (1.4–2 s) at different depths of water (0.35, 0.40 and 0.45 m). A minimum Kt of 0.58 associated with Kr of 0.26 and Kd of 0.78 is obtained with an optimum configuration of Pa = 50%, P = 19.2% and S/D = 0.25. The Kt of the proposed CPHB is about 19 to 35% lesser than that of the perforated hollow pile breakwater under matching test conditions. Overall, providing the perforations is found to be effective in enhancing the wave attenuation capability by up to 12.4%. Further, empirical equations are formulated and validated with the experimental data. The empirical equations estimate the Kt and Kr values accurately with a high coefficient of determination ( R2 ≥ 0.90).
{"title":"Investigation on innovative pile head breakwater for coastal protection","authors":"Arunakumar Hunasanahally Sathyanarayana, P. Suvarna, Pruthviraj Umesh, K. G. Shirlal","doi":"10.1177/14750902231155677","DOIUrl":"https://doi.org/10.1177/14750902231155677","url":null,"abstract":"Coastal erosion is a global concern that has been augmenting due to the natural evolution of beaches, human activities and sea-level rise. One of the eco-friendly shore protection methods is to dissipate the wave energy by constructing offshore breakwaters. Conical pile head breakwater (CPHB) is one of the eco-friendly innovative offshore structures consisting of closely spaced piles with an enlarged cross-sectional area (conical pile head) in the vicinity of the free surface. In the present study, perforations are incorporated over the conical pile head to achieve higher efficiency by promoting energy dissipation. The influence of the perforations on the performance characteristics, namely wave transmission (Kt), wave reflection (Kr) and energy dissipation (Kd) of the perforated CPHB is comprehensively investigated through physical model studies. The effect of perforations and their distribution around the pile head (Pa), percentage of perforation (P) and size of perforations (S/D) on the wave attenuation characteristics are evaluated to arrive at an optimum configuration. The study is carried out under monochromatic waves of varying wave height (0.06–0.16 m) and wave period (1.4–2 s) at different depths of water (0.35, 0.40 and 0.45 m). A minimum Kt of 0.58 associated with Kr of 0.26 and Kd of 0.78 is obtained with an optimum configuration of Pa = 50%, P = 19.2% and S/D = 0.25. The Kt of the proposed CPHB is about 19 to 35% lesser than that of the perforated hollow pile breakwater under matching test conditions. Overall, providing the perforations is found to be effective in enhancing the wave attenuation capability by up to 12.4%. Further, empirical equations are formulated and validated with the experimental data. The empirical equations estimate the Kt and Kr values accurately with a high coefficient of determination ( R2 ≥ 0.90).","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"22 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79786023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-03DOI: 10.1177/14750902221150285
J. Bowker, M. Tan, N. Townsend
This paper presents a concept design for an Autonomous Vehicle (AxV) capable of operating throughout the ocean space; air, surface and subsea. With current autonomous platforms limited in their operation, for example aerial platforms only operate in air, ASVs only operate on the ocean surface and AUVs operate subsea, a platform which can operate, transiting and transitioning in and between air, surface and subsea, providing increased mobility is very attractive. In this paper, a novel AxV platform is described. The governing equations are presented, describing each operational mode and the transitions between modes (air to surface, surface to subsea, subsea to surface, surface to air). Results are presented based on the dimensions of existing vehicles, showing that the system is theoretically feasible.
{"title":"AxV: An autonomous vehicle concept capable of operating throughout the ocean space: air, surface and subsea","authors":"J. Bowker, M. Tan, N. Townsend","doi":"10.1177/14750902221150285","DOIUrl":"https://doi.org/10.1177/14750902221150285","url":null,"abstract":"This paper presents a concept design for an Autonomous Vehicle (AxV) capable of operating throughout the ocean space; air, surface and subsea. With current autonomous platforms limited in their operation, for example aerial platforms only operate in air, ASVs only operate on the ocean surface and AUVs operate subsea, a platform which can operate, transiting and transitioning in and between air, surface and subsea, providing increased mobility is very attractive. In this paper, a novel AxV platform is described. The governing equations are presented, describing each operational mode and the transitions between modes (air to surface, surface to subsea, subsea to surface, surface to air). Results are presented based on the dimensions of existing vehicles, showing that the system is theoretically feasible.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"125 1","pages":"918 - 928"},"PeriodicalIF":1.8,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75813173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-31DOI: 10.1177/14750902231152337
Jiang-hai Wu, Z. Yin, Yu-dong Sun
Fluid-filled pipelines are widely used in engineering and industry. An analysis of the frequency dynamic responses of three-dimensional pipes is presented in this paper. A general formulation is developed based on an impedance matrix transmission approach in which a T-shaped pipe system can be assembled from three straight pipes. For validation purposes, numerical results are compared with data given by finite element method (FEM) software, previous literature, and an experiment. In the experiment, the three-dimensional pipe system is suspended horizontally on spring wires and is excited in the X and Y directions. It is found that the results calculated using the proposed method match the experimental results well. A dimensionless analysis of Poisson’s coupling is then carried out, and the junction coupling of the branch pipe is analyzed as a function of its angle. Through this work, it is shown that the proposed method is efficient and can be used to predict the vibration of three-dimensional pipes.
{"title":"A study of the frequency response of fluid-structure interactions in a three-dimensional fluid-filled pipe system using an impedance synthesis method","authors":"Jiang-hai Wu, Z. Yin, Yu-dong Sun","doi":"10.1177/14750902231152337","DOIUrl":"https://doi.org/10.1177/14750902231152337","url":null,"abstract":"Fluid-filled pipelines are widely used in engineering and industry. An analysis of the frequency dynamic responses of three-dimensional pipes is presented in this paper. A general formulation is developed based on an impedance matrix transmission approach in which a T-shaped pipe system can be assembled from three straight pipes. For validation purposes, numerical results are compared with data given by finite element method (FEM) software, previous literature, and an experiment. In the experiment, the three-dimensional pipe system is suspended horizontally on spring wires and is excited in the X and Y directions. It is found that the results calculated using the proposed method match the experimental results well. A dimensionless analysis of Poisson’s coupling is then carried out, and the junction coupling of the branch pipe is analyzed as a function of its angle. Through this work, it is shown that the proposed method is efficient and can be used to predict the vibration of three-dimensional pipes.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"8 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82678188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-31DOI: 10.1177/14750902221149291
Muhittin Orhan, M. Celik
Fault detection and diagnostics (FDD) have great potential to enable safety, efficiency, and reliability measures of critical machinery systems. However, it is clear that there is a lack of systematic literature review to identify and classify the FDD studies conducted within the scope of marine engineering. This paper offers a systematic review of FDD models particular to marine machinery and systems. The numbers of 72 core articles were highlighted through a comprehensive literature review conducted in the 2002–2022 period. The studies are classified based on the mostly utilized methods such as data-driven, model-based, knowledge-based, and new generation-hybrid. In addition, new generation and hybrid methods are discussed in detail. The experimental environment (i.e. shipboard, labs, simulator) and technical details of the conducted studies are extensively discussed. While 56.94% of the examined studies are related to the main engine, 43.06% of them are related to auxiliary engines. In addition, the main and auxiliary engine studies are also divided into subject headings and examined in detail. Given the recent developments in green and smart maritime concepts, a future research agenda of the FDD studies on marine machinery systems is then pinpointed. Consequently, the study stimulates scholars interested in FDD while it enables innovative ideas for marine engineers, technology providers, ship operators, and maritime entrepreneurs.
{"title":"A literature review and future research agenda on fault detection and diagnosis studies in marine machinery systems","authors":"Muhittin Orhan, M. Celik","doi":"10.1177/14750902221149291","DOIUrl":"https://doi.org/10.1177/14750902221149291","url":null,"abstract":"Fault detection and diagnostics (FDD) have great potential to enable safety, efficiency, and reliability measures of critical machinery systems. However, it is clear that there is a lack of systematic literature review to identify and classify the FDD studies conducted within the scope of marine engineering. This paper offers a systematic review of FDD models particular to marine machinery and systems. The numbers of 72 core articles were highlighted through a comprehensive literature review conducted in the 2002–2022 period. The studies are classified based on the mostly utilized methods such as data-driven, model-based, knowledge-based, and new generation-hybrid. In addition, new generation and hybrid methods are discussed in detail. The experimental environment (i.e. shipboard, labs, simulator) and technical details of the conducted studies are extensively discussed. While 56.94% of the examined studies are related to the main engine, 43.06% of them are related to auxiliary engines. In addition, the main and auxiliary engine studies are also divided into subject headings and examined in detail. Given the recent developments in green and smart maritime concepts, a future research agenda of the FDD studies on marine machinery systems is then pinpointed. Consequently, the study stimulates scholars interested in FDD while it enables innovative ideas for marine engineers, technology providers, ship operators, and maritime entrepreneurs.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"31 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85592155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-28DOI: 10.1177/14750902221141749
M. Semini, Clara Patek, P. O. Brett, Jose Jorge Garcia Agis, J. Strandhagen, J. Vatn
The build strategy of a ship specifies what is to be produced how, when, where and with what resources. Although it has been emphasised to play an important role in determining shipbuilding time and cost, scientific research on build strategy is limited. In this study, we focus on three interrelated build strategic factors of particular importance in European shipbuilding: hull production offshoring, pre-erection outfitting and the overlap between engineering and production. The study investigates how each of these three factors relates to physical ship production time and to total ship delivery time from contract signing to delivery. We use multiple linear regression on data about European shipyards and the ships they have built, which were obtained from a questionnaire and ship databases. The sample consists of 76 specialised ships, predominantly offshore support vessels, fishing vessels, ferries and other non-cargo carrying vessels, built at 24 European yards. The results provide evidence that yards practicing hull production offshoring have shorter ship production and delivery times than yards building the hulls at their own premises, even though the practice of offshoring itself is likely to have an adverse effect on shipbuilding time. The study also found a significant relationship between the level of pre-erection outfitting and physical production time. On the other hand, overlapping engineering and production only seems to have a limited impact on the production and the delivery time. Several of our results challenge established thinking and provide new insights into the factors affecting production and delivery time in European shipbuilding.
{"title":"Some relationships between build strategy and shipbuilding time in European shipbuilding","authors":"M. Semini, Clara Patek, P. O. Brett, Jose Jorge Garcia Agis, J. Strandhagen, J. Vatn","doi":"10.1177/14750902221141749","DOIUrl":"https://doi.org/10.1177/14750902221141749","url":null,"abstract":"The build strategy of a ship specifies what is to be produced how, when, where and with what resources. Although it has been emphasised to play an important role in determining shipbuilding time and cost, scientific research on build strategy is limited. In this study, we focus on three interrelated build strategic factors of particular importance in European shipbuilding: hull production offshoring, pre-erection outfitting and the overlap between engineering and production. The study investigates how each of these three factors relates to physical ship production time and to total ship delivery time from contract signing to delivery. We use multiple linear regression on data about European shipyards and the ships they have built, which were obtained from a questionnaire and ship databases. The sample consists of 76 specialised ships, predominantly offshore support vessels, fishing vessels, ferries and other non-cargo carrying vessels, built at 24 European yards. The results provide evidence that yards practicing hull production offshoring have shorter ship production and delivery times than yards building the hulls at their own premises, even though the practice of offshoring itself is likely to have an adverse effect on shipbuilding time. The study also found a significant relationship between the level of pre-erection outfitting and physical production time. On the other hand, overlapping engineering and production only seems to have a limited impact on the production and the delivery time. Several of our results challenge established thinking and provide new insights into the factors affecting production and delivery time in European shipbuilding.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"50 3 1","pages":"658 - 676"},"PeriodicalIF":1.8,"publicationDate":"2023-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87695919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-27DOI: 10.1177/14750902221149468
Sadegh Khaleghi, R. Moghaddam, M. Sistani
This article presents temporal-difference (TD) learning which is a combination of Monte Carlo and dynamic programing (DP) as a Method for controlling single-body wave energy converters (WECs). Since TD methods are designed to solve the prediction problems, we use this feature to maximize the energy captured from the sea waves. The entered force to the buoy system is addressed implicitly in the state matrix to design the problem into a TD framework. In order to enhance the captured power by the WEC, the control method is built to have an online active control. This will help the device to predict the best controller based on its previous experiences in the same situations. Two methods of TD, Q-Learning and SARSA, are used and the features are analyzed and several testing functions are carried out in simulation part. To perform on-line optimal control, a force control has acted as a controller and TD coefficients are tuned at a proper rate significantly after specific number of episodes. The power of suggested TD methods is compared to PGM, IPOPT and with other learning control strategies. Several computer simulations were carried out to evaluate the controller effectiveness by applying different sea-states and analyzing the resultant WEC dynamics.
{"title":"Online maximization of extracted energy in sea wave energy converters using temporal-difference learning","authors":"Sadegh Khaleghi, R. Moghaddam, M. Sistani","doi":"10.1177/14750902221149468","DOIUrl":"https://doi.org/10.1177/14750902221149468","url":null,"abstract":"This article presents temporal-difference (TD) learning which is a combination of Monte Carlo and dynamic programing (DP) as a Method for controlling single-body wave energy converters (WECs). Since TD methods are designed to solve the prediction problems, we use this feature to maximize the energy captured from the sea waves. The entered force to the buoy system is addressed implicitly in the state matrix to design the problem into a TD framework. In order to enhance the captured power by the WEC, the control method is built to have an online active control. This will help the device to predict the best controller based on its previous experiences in the same situations. Two methods of TD, Q-Learning and SARSA, are used and the features are analyzed and several testing functions are carried out in simulation part. To perform on-line optimal control, a force control has acted as a controller and TD coefficients are tuned at a proper rate significantly after specific number of episodes. The power of suggested TD methods is compared to PGM, IPOPT and with other learning control strategies. Several computer simulations were carried out to evaluate the controller effectiveness by applying different sea-states and analyzing the resultant WEC dynamics.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"33 1","pages":"565 - 578"},"PeriodicalIF":1.8,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90519278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-27DOI: 10.1177/14750902221149078
Xin Hu, Zhongyu Sun, Rui Wang, Shuwen Feng
This paper proposes an adaptive generalized predictive control for dynamic positioning of ships with unknown model parameters and unknown time-varying environmental disturbances. The controlled auto-regressive integrated moving average (CARIMA) model is employed to describe the movements of ships with model parameter and disturbance uncertainties. The recursive least square method with forgetting factor is utilized to design adaptive laws to estimate the CARIMA model parameters online. Considering both the positioning accuracy and the change intensity of control increments, a cost function is constructed. The optimal control increments that minimize the cost function are obtained by using Lagrange multiplier method. Then, the adaptive control law is designed to maintain ship’s position and heading at desired values. Finally, simulation studies in different cases are carried out and simulation results demonstrate the effectiveness of the proposed control scheme.
{"title":"Adaptive generalized predictive control for dynamic positioning system of ships with model unknown parameters","authors":"Xin Hu, Zhongyu Sun, Rui Wang, Shuwen Feng","doi":"10.1177/14750902221149078","DOIUrl":"https://doi.org/10.1177/14750902221149078","url":null,"abstract":"This paper proposes an adaptive generalized predictive control for dynamic positioning of ships with unknown model parameters and unknown time-varying environmental disturbances. The controlled auto-regressive integrated moving average (CARIMA) model is employed to describe the movements of ships with model parameter and disturbance uncertainties. The recursive least square method with forgetting factor is utilized to design adaptive laws to estimate the CARIMA model parameters online. Considering both the positioning accuracy and the change intensity of control increments, a cost function is constructed. The optimal control increments that minimize the cost function are obtained by using Lagrange multiplier method. Then, the adaptive control law is designed to maintain ship’s position and heading at desired values. Finally, simulation studies in different cases are carried out and simulation results demonstrate the effectiveness of the proposed control scheme.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"55 1","pages":"579 - 587"},"PeriodicalIF":1.8,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75320351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-22DOI: 10.1177/14750902221150050
Ross O’Connell, Jimmy Murphy, F. Devoy McAuliffe, G. Dalton
Accurate and up-to-date Geographic Information System (GIS) and Techno Economic (TE) tools are pertinent to helping to develop the renewable energy sector. This paper reviews the state of the art in existing GIS and TE tools for renewable energy and proposes a methodology to develop a coupled GIS-TE software tool that is geared specifically to Marine Renewable Energy (MRE) applications and bespoke to Irish and Western UK waters. Methods for approaching GIS and TE analysis within existing tools for renewable energy are presented and compared. Many existing tools of this nature have some interesting functionalities, but most are unsuitable for MRE; are limited by a lack of information on both the technology and the site; and focus solely either on GIS or TE aspects of analysis. Additionally, almost all of those with a TE focus are not open access. The proposed tool aims to incorporate increased resolution and site relevance of resource data; the most up-to-date geospatial data for site selection; and will provide site specific TE indicators and recommendations for contemporary MRE devices. The result will be the development of an open-access GIS-TE software tool for MRE.
{"title":"A review of geographic information system (GIS) and techno economic (TE) software tools for renewable energy and methodology to develop a coupled GIS-TE software tool for marine renewable energy (MRE)","authors":"Ross O’Connell, Jimmy Murphy, F. Devoy McAuliffe, G. Dalton","doi":"10.1177/14750902221150050","DOIUrl":"https://doi.org/10.1177/14750902221150050","url":null,"abstract":"Accurate and up-to-date Geographic Information System (GIS) and Techno Economic (TE) tools are pertinent to helping to develop the renewable energy sector. This paper reviews the state of the art in existing GIS and TE tools for renewable energy and proposes a methodology to develop a coupled GIS-TE software tool that is geared specifically to Marine Renewable Energy (MRE) applications and bespoke to Irish and Western UK waters. Methods for approaching GIS and TE analysis within existing tools for renewable energy are presented and compared. Many existing tools of this nature have some interesting functionalities, but most are unsuitable for MRE; are limited by a lack of information on both the technology and the site; and focus solely either on GIS or TE aspects of analysis. Additionally, almost all of those with a TE focus are not open access. The proposed tool aims to incorporate increased resolution and site relevance of resource data; the most up-to-date geospatial data for site selection; and will provide site specific TE indicators and recommendations for contemporary MRE devices. The result will be the development of an open-access GIS-TE software tool for MRE.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"17 1","pages":"547 - 564"},"PeriodicalIF":1.8,"publicationDate":"2023-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74220273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-18DOI: 10.1177/14750902221145785
Wen Jiang, Xin Shen, Liangliang Liu, Tao Bian
In this work, numerical investigations were performed to the study the effect of blade number on the hydrodynamic performance of shaftless Rim-driven Thruster (RDT) with certain blade area ratio and pitch ratio. The work investigated and compared the thrust coefficient, torque coefficient and efficiency of the RDTs with different blade numbers. Additionally, this work detected and analyzed the pressure distribution on the blade surface and velocity distribution around the blade and in the wake. The results demonstrate that for a certain advance coefficient, the thrust coefficient and torque coefficient of the RDT increase with the blade number, however the efficiency of the RDT decreases with the increase of blade number. For the same cross-section and advance coefficient, the 7-blade RDT has higher thrust and torque than the 3-blade RDT due to the large friction and pressure difference between the suction and pressure surfaces. The high velocity of both RDTs appears at the junction between each blade and the duct, and the 7-blade RDT has higher velocity in the wake and in the cross-section than the 3-blade RDT. The 3-blade RDT has the high pressure at the leading edge on the suction surface of each blade. However, the 7-blade RDT has not only the high pressure at the leading edge, but also the high negative pressure at the blade root on the suction surface of each blade, so 7-blade RDT has higher torque that 3-blade RDT.
{"title":"Numerical analysis of the effect of the blade number on the hydrodynamic performance of shaftless rim-driven thruster","authors":"Wen Jiang, Xin Shen, Liangliang Liu, Tao Bian","doi":"10.1177/14750902221145785","DOIUrl":"https://doi.org/10.1177/14750902221145785","url":null,"abstract":"In this work, numerical investigations were performed to the study the effect of blade number on the hydrodynamic performance of shaftless Rim-driven Thruster (RDT) with certain blade area ratio and pitch ratio. The work investigated and compared the thrust coefficient, torque coefficient and efficiency of the RDTs with different blade numbers. Additionally, this work detected and analyzed the pressure distribution on the blade surface and velocity distribution around the blade and in the wake. The results demonstrate that for a certain advance coefficient, the thrust coefficient and torque coefficient of the RDT increase with the blade number, however the efficiency of the RDT decreases with the increase of blade number. For the same cross-section and advance coefficient, the 7-blade RDT has higher thrust and torque than the 3-blade RDT due to the large friction and pressure difference between the suction and pressure surfaces. The high velocity of both RDTs appears at the junction between each blade and the duct, and the 7-blade RDT has higher velocity in the wake and in the cross-section than the 3-blade RDT. The 3-blade RDT has the high pressure at the leading edge on the suction surface of each blade. However, the 7-blade RDT has not only the high pressure at the leading edge, but also the high negative pressure at the blade root on the suction surface of each blade, so 7-blade RDT has higher torque that 3-blade RDT.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"56 1","pages":"588 - 596"},"PeriodicalIF":1.8,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83966885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-15DOI: 10.1177/14750902221147623
Jiayu Diao, Weimin Li, Xueqing Yuan, Kai Jiang, Yifeng Zhao
It is necessary to investigate the dynamic performance during autonomous underwater vehicle (AUV) underwater docking to aid in control and to enhance docking safety. Therefore, in this study, the docking hydrodynamic characteristics (including the docking system’s streamline, velocity vector, and surface pressure during the overall docking process) of the AUV with conical hood dock are determined by using the dynamic grid technology, and the water drag force situations of the AUV docking with conical hood dock are studied from the perspectives of different velocities, accelerations, navigation modes, and structures. Additionally, the multiple nonlinear regression fits and the preliminary docking test were examined. Furthermore, brief inferences obtained are as follows: First, the maximum pressure is situated at the upstream surface of the dock conical hood and the head of the AUV, and the maximum rotation angle of the streamline is situated at the outermost ring of dock conical hood. Within a specified range, the rotation angle of the streamline affected by the conical hood progressively declines as the AUV docks deeper into the conical hood. Second, low velocity uniform docking, deceleration docking, and chase docking can reduce the drag force to a certain extent during docking. Finally, both arc shape and mesh structure can decrease the water drag force of docking to a specified degree. This research provides a theoretical basis and reference methods for the dynamic research of the docking system, and other related research can be carried out through the methods and results of this research.
{"title":"Study on influencing factors of hydrodynamics based on AUV docking with conical dock","authors":"Jiayu Diao, Weimin Li, Xueqing Yuan, Kai Jiang, Yifeng Zhao","doi":"10.1177/14750902221147623","DOIUrl":"https://doi.org/10.1177/14750902221147623","url":null,"abstract":"It is necessary to investigate the dynamic performance during autonomous underwater vehicle (AUV) underwater docking to aid in control and to enhance docking safety. Therefore, in this study, the docking hydrodynamic characteristics (including the docking system’s streamline, velocity vector, and surface pressure during the overall docking process) of the AUV with conical hood dock are determined by using the dynamic grid technology, and the water drag force situations of the AUV docking with conical hood dock are studied from the perspectives of different velocities, accelerations, navigation modes, and structures. Additionally, the multiple nonlinear regression fits and the preliminary docking test were examined. Furthermore, brief inferences obtained are as follows: First, the maximum pressure is situated at the upstream surface of the dock conical hood and the head of the AUV, and the maximum rotation angle of the streamline is situated at the outermost ring of dock conical hood. Within a specified range, the rotation angle of the streamline affected by the conical hood progressively declines as the AUV docks deeper into the conical hood. Second, low velocity uniform docking, deceleration docking, and chase docking can reduce the drag force to a certain extent during docking. Finally, both arc shape and mesh structure can decrease the water drag force of docking to a specified degree. This research provides a theoretical basis and reference methods for the dynamic research of the docking system, and other related research can be carried out through the methods and results of this research.","PeriodicalId":20667,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment","volume":"183 1","pages":"929 - 939"},"PeriodicalIF":1.8,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77653862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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