Pub Date : 2020-06-27DOI: 10.3329/jname.v17i1.33734
S. Reddy, P. B. A. Reddy
The main objective of this paper is to study the homogeneous-heterogeneous reactions on magnetohydrodynamic flow over a nonlinear stretching sheet.Water/blood is taken as the base fluid for the suspension of single-wall carbon nanotubes. The governing non-linear partial differential equations are transformed into ordinary differential equations which are solved numerically by utilizing the fourth order Runge-Kutta method with shooting technique. Graphical results have been presented for the velocity, temperature, concentration, local skin friction coefficient and local Nusselt number for various physical parameters of interest. Comparisons with previously published data are performed and the results are found to be excellent agreement.
{"title":"Biomathematical analysis for the carbon nanotubes effects in the stagnation point flow towards a nonlinear stretching sheet with homogeneous-heterogeneous reaction","authors":"S. Reddy, P. B. A. Reddy","doi":"10.3329/jname.v17i1.33734","DOIUrl":"https://doi.org/10.3329/jname.v17i1.33734","url":null,"abstract":"The main objective of this paper is to study the homogeneous-heterogeneous reactions on magnetohydrodynamic flow over a nonlinear stretching sheet.Water/blood is taken as the base fluid for the suspension of single-wall carbon nanotubes. The governing non-linear partial differential equations are transformed into ordinary differential equations which are solved numerically by utilizing the fourth order Runge-Kutta method with shooting technique. Graphical results have been presented for the velocity, temperature, concentration, local skin friction coefficient and local Nusselt number for various physical parameters of interest. Comparisons with previously published data are performed and the results are found to be excellent agreement.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42325219","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 : 2020-06-22DOI: 10.3329/jname.v17i1.37777
A. P. Baitharu, S. Sahoo, G. Dash
The present problem deals with a radiative second grade fluid flow through a porous medium over a semi infinite stretching sheet. In the present study, governing equations for the third grade fluid has been formulated. However, computation has been made for a second grade fluid as a particular case of third grade of fluid. The bounding surface is subjected to power law temperature distribution and heat flux. Confluent hypergeometric function and Runge-Kutta method of fourth order are used to solve the transformed non-linear governing equations. The physical variables such as velocity, temperature and concentration are studied in response to radiative heat transfer, electromagnetic mechanical force and porosity of the medium. The important findings of the present study are: the applied transverse magnetic field prevents the growth of boundary layer but accelerates the mass transfer; the presence of porous medium in a higher Reynolds number-fluid reduces the skin friction which is desirable for maintaining laminarity of flow and also for reduction of heat transfer rate at the surface; the temperature distribution decreases with the thermal radiation for both PST and PHF cases. In asymptotic case, presence of thermal radiation improves thermal stability.
{"title":"Heat and mass transfer effect on a radiative second grade MHD flow in a porous medium over a stretching sheet","authors":"A. P. Baitharu, S. Sahoo, G. Dash","doi":"10.3329/jname.v17i1.37777","DOIUrl":"https://doi.org/10.3329/jname.v17i1.37777","url":null,"abstract":"The present problem deals with a radiative second grade fluid flow through a porous medium over a semi infinite stretching sheet. In the present study, governing equations for the third grade fluid has been formulated. However, computation has been made for a second grade fluid as a particular case of third grade of fluid. The bounding surface is subjected to power law temperature distribution and heat flux. Confluent hypergeometric function and Runge-Kutta method of fourth order are used to solve the transformed non-linear governing equations. The physical variables such as velocity, temperature and concentration are studied in response to radiative heat transfer, electromagnetic mechanical force and porosity of the medium. The important findings of the present study are: the applied transverse magnetic field prevents the growth of boundary layer but accelerates the mass transfer; the presence of porous medium in a higher Reynolds number-fluid reduces the skin friction which is desirable for maintaining laminarity of flow and also for reduction of heat transfer rate at the surface; the temperature distribution decreases with the thermal radiation for both PST and PHF cases. In asymptotic case, presence of thermal radiation improves thermal stability.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48363425","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 : 2020-06-20DOI: 10.3329/jname.v17i1.42203
S. Galic, Zvonimir Lušić, Tatjana Stanivuk
E-learning has become a widespread form of education as it allows the users a relatively easy access to needed information. E-learning has also been present in maritime affairs, although not so ubiquitous as in other economy sectors. Sea-borne shipping is one of the most stringently controlled industries, with a number of complex regulations and standards. This paper analyses learning methodologies and discusses the economic justification of implementing e-learning systems at global level, with an emphasis on the growing e-learning industry, corporate segment of e-learning, massive open online course market, and the importance of the micro-learning concept. In addition, this study analyses the present systems of seafarers’ education and the potentials, strengths and shortcomings of the conventional learning, e-learning and m-learning. Moreover, the recent application of e-learning in maritime affairs and the need of further research of the e-learning impacts in maritime affairs are examined. Finally, the presented information and discussion result in the logic matrix analysis and the SWOT analysis of e-learning, aiming to define the strengths, weaknesses, logic of action, goals and potentials of the implementation of e-learning in maritime affairs. Keywords: E-learning, education of seafarers, STCW Convention, IMO.
{"title":"E-learning in maritime affairs","authors":"S. Galic, Zvonimir Lušić, Tatjana Stanivuk","doi":"10.3329/jname.v17i1.42203","DOIUrl":"https://doi.org/10.3329/jname.v17i1.42203","url":null,"abstract":"E-learning has become a widespread form of education as it allows the users a relatively easy access to needed information. E-learning has also been present in maritime affairs, although not so ubiquitous as in other economy sectors. Sea-borne shipping is one of the most stringently controlled industries, with a number of complex regulations and standards. This paper analyses learning methodologies and discusses the economic justification of implementing e-learning systems at global level, with an emphasis on the growing e-learning industry, corporate segment of e-learning, massive open online course market, and the importance of the micro-learning concept. In addition, this study analyses the present systems of seafarers’ education and the potentials, strengths and shortcomings of the conventional learning, e-learning and m-learning. Moreover, the recent application of e-learning in maritime affairs and the need of further research of the e-learning impacts in maritime affairs are examined. Finally, the presented information and discussion result in the logic matrix analysis and the SWOT analysis of e-learning, aiming to define the strengths, weaknesses, logic of action, goals and potentials of the implementation of e-learning in maritime affairs. \u0000Keywords: E-learning, education of seafarers, STCW Convention, IMO.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46210265","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 : 2020-06-20DOI: 10.3329/jname.v17i1.42001
T. Nasar, S. Sannasiraj, V. Sundar
An experimental study has been carried out to assess the sloshing pressure expected on the side walls of the tank and on top panel. A liquid fill level with an aspect ratio (hs /l, where hs is the static liquid depth and l is the tank length) of 0.488 is considered which corresponds to 75% liquid fill level. In view of suppressing sloshing oscillation and consequent sloshing pressure, the baffle wall configurations such as porous wall at l/2 and porous walls at l/3 and 2l/3 were adopted. Three porosities of 15%, 20.2%, and 25.2% were considered. The sloshing tank is fitted into the freely floating barge of model scale 1:43. The barge is kept inside the wave flume in the beam sea conditions. The effects of wave excitation frequencies and on the sloshing pressure variation have been studied in detail. For comparison purpose, solid wall placed at l/2 (Nasar and Sannasiraj, 2018) is also considered and, the salient results are herein reported.
{"title":"Effect of porous baffle on sloshing pressure distribution in a barge mounted container subjected to regular wave excitation","authors":"T. Nasar, S. Sannasiraj, V. Sundar","doi":"10.3329/jname.v17i1.42001","DOIUrl":"https://doi.org/10.3329/jname.v17i1.42001","url":null,"abstract":"An experimental study has been carried out to assess the sloshing pressure expected on the side walls of the tank and on top panel. A liquid fill level with an aspect ratio (hs /l, where hs is the static liquid depth and l is the tank length) of 0.488 is considered which corresponds to 75% liquid fill level. In view of suppressing sloshing oscillation and consequent sloshing pressure, the baffle wall configurations such as porous wall at l/2 and porous walls at l/3 and 2l/3 were adopted. Three porosities of 15%, 20.2%, and 25.2% were considered. The sloshing tank is fitted into the freely floating barge of model scale 1:43. The barge is kept inside the wave flume in the beam sea conditions. The effects of wave excitation frequencies and on the sloshing pressure variation have been studied in detail. For comparison purpose, solid wall placed at l/2 (Nasar and Sannasiraj, 2018) is also considered and, the salient results are herein reported.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48917774","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 : 2020-06-20DOI: 10.3329/jname.v17i1.40942
K. Prasad, P. R. Yasa
In this paper, the effect of slip on Micropolar fluid in a circular tube of non-uniform cross-section with multiple stenosis have been studied. The coupled equations governing to the flow are calculated by using Homotopy Perturbation Method. The effects of various parameters with heights of the stenosis on the resistance to the flow and wall shear stress have been studied by deriving the expressions for the flow characteristics and their solutions have been obtained. It is found that the resistance to the flow increases with the heights of the stenosis, inclination, Thermophoresis parameter, local temperature Grashof number, local nanoparticle Grashof number, inclination and permeability constant and decreases with Brownian motion parameter. It is found that the shear stress at the wall increases with heights of the stenosis, Brownian motion parameter but decreases with local nanoparticle Grashof number, Thermophoresis parameter and permeability constant. Also, it is observed that the volume of the bolus increases with the increase of permeability constant.
{"title":"Flow of non-Newtonian fluid through a permeable artery having non-uniform cross section with multiple stenosis","authors":"K. Prasad, P. R. Yasa","doi":"10.3329/jname.v17i1.40942","DOIUrl":"https://doi.org/10.3329/jname.v17i1.40942","url":null,"abstract":"In this paper, the effect of slip on Micropolar fluid in a circular tube of non-uniform cross-section with multiple stenosis have been studied. The coupled equations governing to the flow are calculated by using Homotopy Perturbation Method. The effects of various parameters with heights of the stenosis on the resistance to the flow and wall shear stress have been studied by deriving the expressions for the flow characteristics and their solutions have been obtained. It is found that the resistance to the flow increases with the heights of the stenosis, inclination, Thermophoresis parameter, local temperature Grashof number, local nanoparticle Grashof number, inclination and permeability constant and decreases with Brownian motion parameter. It is found that the shear stress at the wall increases with heights of the stenosis, Brownian motion parameter but decreases with local nanoparticle Grashof number, Thermophoresis parameter and permeability constant. Also, it is observed that the volume of the bolus increases with the increase of permeability constant.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47004644","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 : 2019-12-31DOI: 10.3329/jname.v16i2.40585
I. Zahan, R. Nasrin, M. Alim
A numerical analysis has been conducted to show the effects of magnetohydrodynamic (MHD) and Joule heating on heat transfer phenomenon in a lid driven triangular cavity. The heat transfer fluid (HTF) has been considered as water based hybrid nanofluid composed of equal quantities of Cu and TiO2 nanoparticles. The bottom wall of the cavity is undulated in sinusoidal pattern and cooled isothermally. The left vertical wall of the cavity is heated while the inclined side is insulated. The two dimensional governing partial differential equations of heat transfer and fluid flow with appropriate boundary conditions have been solved by using Galerkin's finite element method built in COMSOL Multyphysics. The effects of Hartmann number, Joule heating, number of undulation and Richardson number on the flow structure and heat transfer characteristics have been studied in details. The values of Prandtl number and solid volume fraction of hybrid nanoparticles have been considered as fixed. Also, the code validation has been shown. The numerical results have been presented in terms of streamlines, isotherms and average Nusselt number of the hybrid nanofluid for different values of governing parameters. The comparison of heat transfer rate by using hybrid nanofluid, Cu-water nanofluid, TiO2 -water nanofluid and clear water has been also shown. Increasing wave number from 0 to 3 enhances the heat transfer rate by 16.89%. The enhanced rate of mean Nusselt number for hybrid nanofluid is found as 4.11% compared to base fluid.
{"title":"Mixed convective hybrid nanofluid flow in lid-driven undulated cavity: effect of MHD and Joule heating","authors":"I. Zahan, R. Nasrin, M. Alim","doi":"10.3329/jname.v16i2.40585","DOIUrl":"https://doi.org/10.3329/jname.v16i2.40585","url":null,"abstract":"A numerical analysis has been conducted to show the effects of magnetohydrodynamic (MHD) and Joule heating on heat transfer phenomenon in a lid driven triangular cavity. The heat transfer fluid (HTF) has been considered as water based hybrid nanofluid composed of equal quantities of Cu and TiO2 nanoparticles. The bottom wall of the cavity is undulated in sinusoidal pattern and cooled isothermally. The left vertical wall of the cavity is heated while the inclined side is insulated. The two dimensional governing partial differential equations of heat transfer and fluid flow with appropriate boundary conditions have been solved by using Galerkin's finite element method built in COMSOL Multyphysics. The effects of Hartmann number, Joule heating, number of undulation and Richardson number on the flow structure and heat transfer characteristics have been studied in details. The values of Prandtl number and solid volume fraction of hybrid nanoparticles have been considered as fixed. Also, the code validation has been shown. The numerical results have been presented in terms of streamlines, isotherms and average Nusselt number of the hybrid nanofluid for different values of governing parameters. The comparison of heat transfer rate by using hybrid nanofluid, Cu-water nanofluid, TiO2 -water nanofluid and clear water has been also shown. Increasing wave number from 0 to 3 enhances the heat transfer rate by 16.89%. The enhanced rate of mean Nusselt number for hybrid nanofluid is found as 4.11% compared to base fluid.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/jname.v16i2.40585","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46106335","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 : 2019-12-29DOI: 10.3329/jname.v16i2.29526
U. S. Rajput, G. Kumar
This research investigates the effects of radiation, chemical reaction and porosity of the medium on unsteady flow of a viscous, incompressible and electrically conducting fluid past an exponentially accelerated vertical plate with variable wall temperature and mass diffusion in the presence of transversely applied uniform magnetic field. The plate temperature and the concentration level near the plate increase linearly with time. The fluid model under consideration has been solved by Laplace transform technique. The model contains equations of motion, diffusion equation and equation of energy. To analyze the solution of the model, reasonable sets of the values of the parameters have been considered. The numerical data obtained is discussed with the help of graphs and tables. The numerical values obtained for skin-friction, Sherwood number and Nusselt number have been tabulated. It is found that the velocity of fluid increases when the values of permeability parameter, acceleration parameter and radiation parameter are increased. But trend is reversed with the chemical reaction parameter. It means that the velocity decreases when the chemical reaction parameter is increased.
{"title":"Effects of radiation and chemical reaction on MHD flow past a vertical plate with variable temperature and mass diffusion","authors":"U. S. Rajput, G. Kumar","doi":"10.3329/jname.v16i2.29526","DOIUrl":"https://doi.org/10.3329/jname.v16i2.29526","url":null,"abstract":"This research investigates the effects of radiation, chemical reaction and porosity of the medium on unsteady flow of a viscous, incompressible and electrically conducting fluid past an exponentially accelerated vertical plate with variable wall temperature and mass diffusion in the presence of transversely applied uniform magnetic field. The plate temperature and the concentration level near the plate increase linearly with time. The fluid model under consideration has been solved by Laplace transform technique. The model contains equations of motion, diffusion equation and equation of energy. To analyze the solution of the model, reasonable sets of the values of the parameters have been considered. The numerical data obtained is discussed with the help of graphs and tables. The numerical values obtained for skin-friction, Sherwood number and Nusselt number have been tabulated. It is found that the velocity of fluid increases when the values of permeability parameter, acceleration parameter and radiation parameter are increased. But trend is reversed with the chemical reaction parameter. It means that the velocity decreases when the chemical reaction parameter is increased.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/jname.v16i2.29526","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46712272","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 : 2019-12-26DOI: 10.3329/jname.v16i2.42030
G. P. Kumar, V. Prasad, B. H. Nagesh
Abstract: Ship vibrations, airborne and underwater noise levels have always been a challenging topic from performance point of view in ship design, building and operation. The measurement shall help in monitoring the self-noise and the technical state of their machinery mechanism. The vibration levels of the main engine and auxiliary Genset foundation, airborne noise levels of the engine room and underwater self-noise levels of a small mechanized fishing trawler was measured at the jetty in idling condition. The vibration levels on the foundation measured an average value of 0.207 mm/s for main engine and 1.36 mm/s for auxiliary Genset. The airborne noise levels measured 99 dB (A) in the engine room. The peak underwater sound pressure levels measured 162 dB re 1μPa. The response spectra indicate the peak vibration and noise levels in the lower frequency region <1.2 kHz. The machinery excitation forces transferred to the hull surface as pressure fluctuations which generated the airborne and underwater noise levels. Though the measurement limited to jetty conditions, detailed analysis can be useful for detection, classification and tracking of small vessels.
摘要：从性能的角度来看，在船舶设计、建造和运行中，船舶振动、空气和水下噪声水平一直是一个具有挑战性的话题。测量应有助于监测自身噪声及其机械机构的技术状态。在码头空载条件下，测量了一艘小型机械化拖网渔船主机和辅助发电机组基础的振动水平、机舱的空气噪声水平和水下自噪声水平。基础上的振动水平测得的平均值为0.207 mm/s（主机）和1.36 mm/s（辅助发电机组）。机舱内测得的空气噪声级为99 dB（A）。水下声压峰值测量值为162 dB re 1μPa。响应谱表示在<1.2kHz的低频区域内的峰值振动和噪声水平。机械激振力作为压力波动传递到船体表面，从而产生空气和水下噪声水平。尽管测量仅限于码头条件，但详细分析可用于小型船只的检测、分类和跟踪。
{"title":"Measurement of small vessel machinery vibration induced acoustic signature levels","authors":"G. P. Kumar, V. Prasad, B. H. Nagesh","doi":"10.3329/jname.v16i2.42030","DOIUrl":"https://doi.org/10.3329/jname.v16i2.42030","url":null,"abstract":"Abstract: Ship vibrations, airborne and underwater noise levels have always been a challenging topic from performance point of view in ship design, building and operation. The measurement shall help in monitoring the self-noise and the technical state of their machinery mechanism. The vibration levels of the main engine and auxiliary Genset foundation, airborne noise levels of the engine room and underwater self-noise levels of a small mechanized fishing trawler was measured at the jetty in idling condition. The vibration levels on the foundation measured an average value of 0.207 mm/s for main engine and 1.36 mm/s for auxiliary Genset. The airborne noise levels measured 99 dB (A) in the engine room. The peak underwater sound pressure levels measured 162 dB re 1μPa. The response spectra indicate the peak vibration and noise levels in the lower frequency region <1.2 kHz. The machinery excitation forces transferred to the hull surface as pressure fluctuations which generated the airborne and underwater noise levels. Though the measurement limited to jetty conditions, detailed analysis can be useful for detection, classification and tracking of small vessels.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/jname.v16i2.42030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46091055","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 : 2019-12-25DOI: 10.3329/jname.v16i2.41340
M. R. Islam, M. Rahaman, A. Kumar
The production and consumption of oil and other petroleum products have been increasing rapidly over the years, which led to the scarcity of easily retrieved oil due to urbanization. As a result, oil producers are motivated to go to deeper ocean to extract oil and other resources. Offshore platforms in deep water like TLPs are used for exploration of oil and gas from under seabed. But it is challenging to design precisely such type of giant structure in deep sea. It experiences huge forces, motion and other environmental loads which are non-linear, need sophisticated solution techniques and expensive to apply. In the present study, wave exciting forces and motions of free floating TLP are carried out in frequency domain analysis using three-dimensional source distribution techniques within the scope of linear wave theory where six degrees of freedom have been considered. The same geometrical data are used as an input to HydroStar, which is based on linear wave theory. Results obtained from the developed program are compared with the results obtained from HydroStar. The comparison shows a very good agreement. The results obtained from the developed program and HydroStar are also validated with the published results. Forces and motions prediction of TLP is emphasized which has been done precisely in the present work. In future, it will help us to design the TLPs as well as the tendon system in deep sea. Finally, a number of recommendations have been made for further research based on the present study.
{"title":"Study of a TLP motions and forces using 3D source technique","authors":"M. R. Islam, M. Rahaman, A. Kumar","doi":"10.3329/jname.v16i2.41340","DOIUrl":"https://doi.org/10.3329/jname.v16i2.41340","url":null,"abstract":"The production and consumption of oil and other petroleum products have been increasing rapidly over the years, which led to the scarcity of easily retrieved oil due to urbanization. As a result, oil producers are motivated to go to deeper ocean to extract oil and other resources. Offshore platforms in deep water like TLPs are used for exploration of oil and gas from under seabed. But it is challenging to design precisely such type of giant structure in deep sea. It experiences huge forces, motion and other environmental loads which are non-linear, need sophisticated solution techniques and expensive to apply. In the present study, wave exciting forces and motions of free floating TLP are carried out in frequency domain analysis using three-dimensional source distribution techniques within the scope of linear wave theory where six degrees of freedom have been considered. The same geometrical data are used as an input to HydroStar, which is based on linear wave theory. Results obtained from the developed program are compared with the results obtained from HydroStar. The comparison shows a very good agreement. The results obtained from the developed program and HydroStar are also validated with the published results. Forces and motions prediction of TLP is emphasized which has been done precisely in the present work. In future, it will help us to design the TLPs as well as the tendon system in deep sea. Finally, a number of recommendations have been made for further research based on the present study.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/jname.v16i2.41340","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43475846","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 : 2019-12-19DOI: 10.3329/jname.v16i2.35984
Y. Xu, P. Liu, I. Penesis, G. He
A computational hydrodynamics method was formulated and implemented as a tool from screw propeller propulsion to renewable energy performance prediction, design and optimization of horizontal axis turbines. As an example for tidal energy generation, a comparative analysis between screw propellers and horizontal axis turbines was presented, in terms of geometry and motion parameters, inflow velocity analysis and the implementation methodologies. Comparison and analysis are given for a marine propeller model and a horizontal axis turbine model that have experimental measurements available in literature. Analysis and comparison are presented in terms of thrust coefficients, shaft torque/power coefficients, blade surface pressure distributions, and downstream velocity profiles. The effect of number of blades from 2 to 5, of a tidal turbine on hydrodynamic efficiency is also obtained and presented. The key implementation techniques and methodologies are provided in detail for this panel method as a prediction tool for horizontal axis turbines. While the method has been proven to be accurate and robust for many propellers tested in the past, this numerical tool was also validated and presented for both tidal and wind turbines.
{"title":"A panel method for both marine propulsion and renewable energy","authors":"Y. Xu, P. Liu, I. Penesis, G. He","doi":"10.3329/jname.v16i2.35984","DOIUrl":"https://doi.org/10.3329/jname.v16i2.35984","url":null,"abstract":"A computational hydrodynamics method was formulated and implemented as a tool from screw propeller propulsion to renewable energy performance prediction, design and optimization of horizontal axis turbines. As an example for tidal energy generation, a comparative analysis between screw propellers and horizontal axis turbines was presented, in terms of geometry and motion parameters, inflow velocity analysis and the implementation methodologies. Comparison and analysis are given for a marine propeller model and a horizontal axis turbine model that have experimental measurements available in literature. Analysis and comparison are presented in terms of thrust coefficients, shaft torque/power coefficients, blade surface pressure distributions, and downstream velocity profiles. The effect of number of blades from 2 to 5, of a tidal turbine on hydrodynamic efficiency is also obtained and presented. The key implementation techniques and methodologies are provided in detail for this panel method as a prediction tool for horizontal axis turbines. While the method has been proven to be accurate and robust for many propellers tested in the past, this numerical tool was also validated and presented for both tidal and wind turbines.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2019-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/jname.v16i2.35984","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43483237","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：