Pub Date : 2017-06-28DOI: 10.3329/JNAME.V14I1.31632
P. Sadr, A. Kolahdooz, S. A. Eftekhari
Electrical Discharge Machining (EDM) process is one of the most widely used methods for machining. This method is used to form parts that conduct electricity. This method of machining has used for hard materials and therefore select the correct values of parameters are so effective on the quality machining of parts. D3 steel has a high abrasion resistance at low temperatures therefore can be a good candidate for this method of machining. Also because of high hardness and low distortion during heat treatment, using this method is economical for this alloy. The purpose of this paper is to investigate the influence of the main parameters such as voltage, current, pulse duration and pulse off time and the interaction of them to determine the optimal condition for the D3 steel alloy (alloy with DIN 1.2080). Chip removal rate (MRR) and surface quality of parts were evaluated as the output characteristic of the study. The optimum conditions were achieved when the MRR is in the highest value and surface roughness is in the lowest one. For investigation of interaction, two kinds of DOE methods (Taguchi and determinant of optimal experimental design) are used. Then the optimal parameters are investigated with the help of the analysis signal to noise (S/N) and mathematical modeling. The optimize results were tested again and compared. Also the results showed that regression modeling has better accuracy than the S/N analysis. This is because of a greater number of experiments that done in this part and taking into account the interaction parameters in the regression model.
{"title":"The effect of electrical discharge machining parameters on alloy DIN 1.2080 using the Taguchi method and determinant of optimal design of experiments","authors":"P. Sadr, A. Kolahdooz, S. A. Eftekhari","doi":"10.3329/JNAME.V14I1.31632","DOIUrl":"https://doi.org/10.3329/JNAME.V14I1.31632","url":null,"abstract":"Electrical Discharge Machining (EDM) process is one of the most widely used methods for machining. This method is used to form parts that conduct electricity. This method of machining has used for hard materials and therefore select the correct values of parameters are so effective on the quality machining of parts. D3 steel has a high abrasion resistance at low temperatures therefore can be a good candidate for this method of machining. Also because of high hardness and low distortion during heat treatment, using this method is economical for this alloy. The purpose of this paper is to investigate the influence of the main parameters such as voltage, current, pulse duration and pulse off time and the interaction of them to determine the optimal condition for the D3 steel alloy (alloy with DIN 1.2080). Chip removal rate (MRR) and surface quality of parts were evaluated as the output characteristic of the study. The optimum conditions were achieved when the MRR is in the highest value and surface roughness is in the lowest one. For investigation of interaction, two kinds of DOE methods (Taguchi and determinant of optimal experimental design) are used. Then the optimal parameters are investigated with the help of the analysis signal to noise (S/N) and mathematical modeling. The optimize results were tested again and compared. Also the results showed that regression modeling has better accuracy than the S/N analysis. This is because of a greater number of experiments that done in this part and taking into account the interaction parameters in the regression model.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V14I1.31632","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46541553","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 : 2017-06-28DOI: 10.3329/JNAME.V14I1.31165
K. Prasad, S. Thulluri, M. V. Phanikumari
The effects of an overlapping stenosis on blood flow characteristics in an artery have been studied. Blood has been represented by a couple stress fluid. The flow equations have been linearised and the expressions for pressure drop, resistance to the flow and wall shear stress have been derived. The results are shown graphically. It is observed that the resistance to the flow, pressure drop and wall shear stress increases with height and length of the stenosis. And it is noticed that the resistance to the flow and pressure drop decreases with couple stress fluid parameters. But wall shear stress increases with couple stress fluid parameters.
{"title":"Investigation of blood flow through an artery in the presence of overlapping stenosis","authors":"K. Prasad, S. Thulluri, M. V. Phanikumari","doi":"10.3329/JNAME.V14I1.31165","DOIUrl":"https://doi.org/10.3329/JNAME.V14I1.31165","url":null,"abstract":"The effects of an overlapping stenosis on blood flow characteristics in an artery have been studied. Blood has been represented by a couple stress fluid. The flow equations have been linearised and the expressions for pressure drop, resistance to the flow and wall shear stress have been derived. The results are shown graphically. It is observed that the resistance to the flow, pressure drop and wall shear stress increases with height and length of the stenosis. And it is noticed that the resistance to the flow and pressure drop decreases with couple stress fluid parameters. But wall shear stress increases with couple stress fluid parameters.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V14I1.31165","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45061683","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 : 2017-06-28DOI: 10.3329/JNAME.V14I1.28674
M. Rahaman, H. Islam, H. Akimoto, M. R. Islam
Prediction of ship's response in real voyage condition is essential for efficient ship design. At sea, ships rarely voyage in head wave conditions, and mostly prefer oblique waves for lower resistance and better propulsion. This paper provides oblique wave simulation results for a container, tanker and bulk carrier using a commercial potential flow (PF) based solver, HydroSTAR. Although, PF codes have limitation regarding resistance prediction, they are well reliable in predicting ship motion in waves. The paper aims at providing a relative comparison of ship resistance and motion in different heading angles for three major ship models namely KCS, KVLCC2 and JBC. The paper should prove useful to shippers in case of weather routing or route selection for voyage.
{"title":"Motion predictions of ships in actual operating conditions using potential flow based solver","authors":"M. Rahaman, H. Islam, H. Akimoto, M. R. Islam","doi":"10.3329/JNAME.V14I1.28674","DOIUrl":"https://doi.org/10.3329/JNAME.V14I1.28674","url":null,"abstract":"Prediction of ship's response in real voyage condition is essential for efficient ship design. At sea, ships rarely voyage in head wave conditions, and mostly prefer oblique waves for lower resistance and better propulsion. This paper provides oblique wave simulation results for a container, tanker and bulk carrier using a commercial potential flow (PF) based solver, HydroSTAR. Although, PF codes have limitation regarding resistance prediction, they are well reliable in predicting ship motion in waves. The paper aims at providing a relative comparison of ship resistance and motion in different heading angles for three major ship models namely KCS, KVLCC2 and JBC. The paper should prove useful to shippers in case of weather routing or route selection for voyage.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V14I1.28674","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45211548","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 : 2017-06-28DOI: 10.3329/JNAME.V14I1.27967
Jian-Chen Cai, J. Pan, E. Shi-ju, W. Jiao, Dongyun Wang
This paper studies the fluctuating forces on a plane surface beneath a circular cylinder in the subcritical flow regime using two-dimensional computational fluid dynamics (CFD). The turbulent flow fields were calculated via numerical solutions of the NavierStokes (NS) equations without a turbulence model (laminar flow computation), large eddy simulation (LES), and Reynolds-Averaged N-S equations (RANS) approach with the shear-stress transport (SST) turbulence model. The primary goal is to evaluate the performance of 2-D turbulence simulation with different approaches and to have preliminary knowledge of the forces on the plane which is important in studying scours and flow-induced vibration in ocean engineering. Results show that although a coarse mesh scheme can only obtain potential flows, the laminar approach with high mesh resolution can adequately simulate turbulent flows at moderate Reynolds numbers. Spatially, the fluctuating forces on the plane surface due to the flow are significant within three times the cylinder diameter in the downstream, and within one cylinder diameter in the upstream of the cylinder. The pressure fluctuations are approximately two orders of magnitude larger than the shear stress fluctuations. In the frequency domain, the fluctuating forces are significant under twice the vortex-shedding frequency. Within one cylinder diameter in the downstream and upstream regions of the cylinder, the pressure fluctuations on the plane surface are well correlated, while the shear stress is not so well correlated.
本文利用二维计算流体力学(CFD)方法研究了亚临界流态下圆柱体下平面上的波动力。湍流流场的计算分别采用不含湍流模型的Navier - Stokes (N -S)方程(层流计算)、大涡模拟(LES)和含剪切应力输运(SST)湍流模型的reynolds - average N-S方程(RANS)方法。主要目的是评估不同方法的二维湍流模拟性能，并初步了解平面上的力，这对研究海洋工程中的冲刷和流激振动具有重要意义。结果表明，虽然粗网格格式只能获得势流，但具有高网格分辨率的层流方法可以充分模拟中等雷诺数下的湍流。在空间上，流动对平面表面的波动力在下游三倍圆柱体直径范围内显著，在圆柱体上游一倍圆柱体直径范围内显著。压力波动比剪应力波动约大两个数量级。在频域上，在两倍于旋涡脱落频率的情况下，波动力是显著的。在同一圆柱体直径范围内，在圆柱体的上下游区域，平面上的压力波动相关性较好，而剪切应力相关性不太好。
{"title":"A preliminary study of the pressure and shear stress on a plane surface beneath a circular cylinder in turbulent flow fields","authors":"Jian-Chen Cai, J. Pan, E. Shi-ju, W. Jiao, Dongyun Wang","doi":"10.3329/JNAME.V14I1.27967","DOIUrl":"https://doi.org/10.3329/JNAME.V14I1.27967","url":null,"abstract":"This paper studies the fluctuating forces on a plane surface beneath a circular cylinder in the subcritical flow regime using two-dimensional computational fluid dynamics (CFD). The turbulent flow fields were calculated via numerical solutions of the NavierStokes (NS) equations without a turbulence model (laminar flow computation), large eddy simulation (LES), and Reynolds-Averaged N-S equations (RANS) approach with the shear-stress transport (SST) turbulence model. The primary goal is to evaluate the performance of 2-D turbulence simulation with different approaches and to have preliminary knowledge of the forces on the plane which is important in studying scours and flow-induced vibration in ocean engineering. Results show that although a coarse mesh scheme can only obtain potential flows, the laminar approach with high mesh resolution can adequately simulate turbulent flows at moderate Reynolds numbers. Spatially, the fluctuating forces on the plane surface due to the flow are significant within three times the cylinder diameter in the downstream, and within one cylinder diameter in the upstream of the cylinder. The pressure fluctuations are approximately two orders of magnitude larger than the shear stress fluctuations. In the frequency domain, the fluctuating forces are significant under twice the vortex-shedding frequency. Within one cylinder diameter in the downstream and upstream regions of the cylinder, the pressure fluctuations on the plane surface are well correlated, while the shear stress is not so well correlated.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V14I1.27967","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42853792","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 : 2017-06-28DOI: 10.3329/JNAME.V14I1.26523
M. Nakisa, A. Maimun, Y. Ahmed, F. Behrouzi, A. Tarmizi
This research paper investigated the hydrodynamic resistance of Multipurpose Amphibious Vehicles (MAV) due to navigate in low water depth numerically. This type of vehicle and other coastal floating vehicles encounter the problem of a small under keel clearance with river bed. The proper estimation of ship resistance and squat is influence largely on the power calculation in the design stage. The present work describes the effect of shallow water on the Multipurpose Amphibious Vehicles (MAV) resistance at different speed using Computational Fluid Dynamics (CFD) techniques. A comparison in the drag on the hull is illustrated between depth restriction and infinite depth water. This paper provides a wide introduction into the problems of modelling of the restricted water depth effects on the ship behaviour, specifically hydrodynamic resistance and squat using CFD which is applied by ANSYS-CFX14.0.
{"title":"Numerical estimation of shallow water effect on multipurpose amphibious vehicle resistance","authors":"M. Nakisa, A. Maimun, Y. Ahmed, F. Behrouzi, A. Tarmizi","doi":"10.3329/JNAME.V14I1.26523","DOIUrl":"https://doi.org/10.3329/JNAME.V14I1.26523","url":null,"abstract":"This research paper investigated the hydrodynamic resistance of Multipurpose Amphibious Vehicles (MAV) due to navigate in low water depth numerically. This type of vehicle and other coastal floating vehicles encounter the problem of a small under keel clearance with river bed. The proper estimation of ship resistance and squat is influence largely on the power calculation in the design stage. The present work describes the effect of shallow water on the Multipurpose Amphibious Vehicles (MAV) resistance at different speed using Computational Fluid Dynamics (CFD) techniques. A comparison in the drag on the hull is illustrated between depth restriction and infinite depth water. This paper provides a wide introduction into the problems of modelling of the restricted water depth effects on the ship behaviour, specifically hydrodynamic resistance and squat using CFD which is applied by ANSYS-CFX14.0.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V14I1.26523","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43396446","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 : 2017-06-28DOI: 10.3329/JNAME.V14I1.25907
J. V. R. Reddy, V. Sugunamma, N. Sandeep
Through this paper we investigated the heat and mass transfer in chemically reacting radiative Casson fluid flow over a slandering/flat stretching sheet in a slip flow regime with aligned magnetic field. This study is carried out under the influence of non uniform heat source/sink. First we converted the governing equations of the flow into ordinary differential equations by making use of suitable similarity transformations. The obtained non-linear differential equations are solved numerically using Runge-Kutta based shooting technique. Further, graphical representation has been given to study the effects of various physical parameters on velocity, temperature and concentration fields. Also numerical computations has been carried out to investigate the influence of the physical parameters involved in the flow on skin friction, rate of heat and mass transfer coefficients. Through this investigation, it is observed that aligned angle, Casson parameter and velocity slip parameter have the tendency to control the velocity field. Also heat transfer rate in flat stretching sheet is higher than that of slendering stretching sheet. A good agreement of the present results with the existed literature has been observed.
{"title":"Dual solutions for heat and mass transfer in chemically reacting radiative non-Newtonian fluid with aligned magnetic field","authors":"J. V. R. Reddy, V. Sugunamma, N. Sandeep","doi":"10.3329/JNAME.V14I1.25907","DOIUrl":"https://doi.org/10.3329/JNAME.V14I1.25907","url":null,"abstract":"Through this paper we investigated the heat and mass transfer in chemically reacting radiative Casson fluid flow over a slandering/flat stretching sheet in a slip flow regime with aligned magnetic field. This study is carried out under the influence of non uniform heat source/sink. First we converted the governing equations of the flow into ordinary differential equations by making use of suitable similarity transformations. The obtained non-linear differential equations are solved numerically using Runge-Kutta based shooting technique. Further, graphical representation has been given to study the effects of various physical parameters on velocity, temperature and concentration fields. Also numerical computations has been carried out to investigate the influence of the physical parameters involved in the flow on skin friction, rate of heat and mass transfer coefficients. Through this investigation, it is observed that aligned angle, Casson parameter and velocity slip parameter have the tendency to control the velocity field. Also heat transfer rate in flat stretching sheet is higher than that of slendering stretching sheet. A good agreement of the present results with the existed literature has been observed.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V14I1.25907","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43864591","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 : 2016-12-29DOI: 10.3329/JNAME.V13I2.26658
H. Chowdhury, A. Masud
Carbon Nanotubes (CNTs) are identified as exceptional in terms of mechanical, electrical, magnetic and optical properties. CNT based composites are also playing a vital role in several fields of science. In this research, four bundles of CNTs with square Representative Volume Element (RVE) is used and ANSYS Multiphysics 11.0 software is used for simulation purpose. In this study, stress distribution of CNT based Aluminum composite is noticed by changing distances of CNT bundles. Stress distribution and transverse Young’s Modulus are investigated by changing different parameters. From this study it can be known how CNT bundles can be formed together to increase or decrease stress. The brief result is that, if the distance of CNT center from reference point is increased then the stress is decreased.
{"title":"Stress distribution in CNT-Aluminum matrix composite by changing distances between CNT bundles","authors":"H. Chowdhury, A. Masud","doi":"10.3329/JNAME.V13I2.26658","DOIUrl":"https://doi.org/10.3329/JNAME.V13I2.26658","url":null,"abstract":"Carbon Nanotubes (CNTs) are identified as exceptional in terms of mechanical, electrical, magnetic and optical properties. CNT based composites are also playing a vital role in several fields of science. In this research, four bundles of CNTs with square Representative Volume Element (RVE) is used and ANSYS Multiphysics 11.0 software is used for simulation purpose. In this study, stress distribution of CNT based Aluminum composite is noticed by changing distances of CNT bundles. Stress distribution and transverse Young’s Modulus are investigated by changing different parameters. From this study it can be known how CNT bundles can be formed together to increase or decrease stress. The brief result is that, if the distance of CNT center from reference point is increased then the stress is decreased.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2016-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V13I2.26658","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69515477","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 : 2016-12-29DOI: 10.3329/JNAME.V13I2.23537
P. B. A. Reddy
An analysis is carried out to investigate the steady two-dimensional magnetohydrodynamic boundary layer flow of a Casson fluid over an exponentially stretching surface in the presence of thermal radiation and chemical reaction. Velocity, thermal and solutal slips are considered instead of no-slip conditions at the boundary. Stretching velocity, wall temperature and wall concentration are considered in the exponential forms. The non-linear partial differential equations are converted into a system of non-linear ordinary differential equations by similarity transformations. The resultant non-linear ordinary differential equations are solved numerically by fourth order Runge-Kutta method along with shooting technique. The influence of various parameters on the fluid velocity, temperature, concentration, wall skin friction coefficient, the heat transfer coefficient and the Sherwood number have been computed and the results are presented graphically and discussed quantitatively. Comparisons with previously published works are performed on various special cases and are found to be in excellent agreement.
{"title":"MHD boundary layer slip flow of a casson fluid over an exponentially stretching surface in the presence of thermal radiation and chemical reaction","authors":"P. B. A. Reddy","doi":"10.3329/JNAME.V13I2.23537","DOIUrl":"https://doi.org/10.3329/JNAME.V13I2.23537","url":null,"abstract":"An analysis is carried out to investigate the steady two-dimensional magnetohydrodynamic boundary layer flow of a Casson fluid over an exponentially stretching surface in the presence of thermal radiation and chemical reaction. Velocity, thermal and solutal slips are considered instead of no-slip conditions at the boundary. Stretching velocity, wall temperature and wall concentration are considered in the exponential forms. The non-linear partial differential equations are converted into a system of non-linear ordinary differential equations by similarity transformations. The resultant non-linear ordinary differential equations are solved numerically by fourth order Runge-Kutta method along with shooting technique. The influence of various parameters on the fluid velocity, temperature, concentration, wall skin friction coefficient, the heat transfer coefficient and the Sherwood number have been computed and the results are presented graphically and discussed quantitatively. Comparisons with previously published works are performed on various special cases and are found to be in excellent agreement.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2016-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V13I2.23537","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69515426","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 : 2016-12-29DOI: 10.3329/JNAME.V13I2.27774
R. Nasrin, M. A. Alim, M. Hasanuzzzaman
Heat transfer phenomena of flat plate solar collector filled with different nanofluids has been investigated numerically. Galerkin’s Finite Element Method is used to solve the problem. Heat transfer rate, average bulk temperature, average sub-domain velocity, outlet temperature, thermal efficiency, mean entropy generation and Bejan number has been investigated by varying the solid nanoparticle volume fraction of water/Cu, water/Ag and water/Cu/Ag nanofluids from 0% to 3%. It is found that the solid nanoparticle volume fraction has great effect on heat transfer phenomena. It is observed that the increases of the solid volume fraction (up to 2%) enhances the heat transfer rate and collector efficiency where after 2% the rate of change almost constant. Higher heat transfer rate and collector efficiency has been obtained 19% and 13% for water/Ag nanofluid respectively.
{"title":"Assisted convective heat transfer and entropy generation in a solar collector filled with nanofluid","authors":"R. Nasrin, M. A. Alim, M. Hasanuzzzaman","doi":"10.3329/JNAME.V13I2.27774","DOIUrl":"https://doi.org/10.3329/JNAME.V13I2.27774","url":null,"abstract":"Heat transfer phenomena of flat plate solar collector filled with different nanofluids has been investigated numerically. Galerkin’s Finite Element Method is used to solve the problem. Heat transfer rate, average bulk temperature, average sub-domain velocity, outlet temperature, thermal efficiency, mean entropy generation and Bejan number has been investigated by varying the solid nanoparticle volume fraction of water/Cu, water/Ag and water/Cu/Ag nanofluids from 0% to 3%. It is found that the solid nanoparticle volume fraction has great effect on heat transfer phenomena. It is observed that the increases of the solid volume fraction (up to 2%) enhances the heat transfer rate and collector efficiency where after 2% the rate of change almost constant. Higher heat transfer rate and collector efficiency has been obtained 19% and 13% for water/Ag nanofluid respectively.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2016-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V13I2.27774","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69515893","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 : 2016-12-29DOI: 10.3329/JNAME.V13I2.25849
S. Ray, D. Chatterjee, S. Nandy
An unsteady, three-dimensional flow simulation is carried out over the bare hull of the autonomous underwater vehicle currently being developed by CSIR-CMERI, Durgapur, India at various angles of attack with the help of a Finite Volume-based CFD software. The purpose of the study is to provide estimation of various hydrodynamic forces acting on the bare hull at different angles of operation. The operating range of velocity of the vehicle is 0-6 knot (0-3 m/s), considering up to 2 knots of upstream current. For the purpose of the CFD simulation, the widely-implemented RANS approach is used, wherein the turbulent transport equations are solved using the low- Re version of the SST ?-? turbulence model. The motion of the vehicle is considered within a range of the pitch angle (0<=alpha<=20). The results are presented in terms of variations of the relevant hydrodynamic parameters. The effects of the angle of attack on the drag and pressure coefficients are discussed in detail.
{"title":"Unsteady CFD simulation of 3D AUV hull at different angles of attack","authors":"S. Ray, D. Chatterjee, S. Nandy","doi":"10.3329/JNAME.V13I2.25849","DOIUrl":"https://doi.org/10.3329/JNAME.V13I2.25849","url":null,"abstract":"An unsteady, three-dimensional flow simulation is carried out over the bare hull of the autonomous underwater vehicle currently being developed by CSIR-CMERI, Durgapur, India at various angles of attack with the help of a Finite Volume-based CFD software. The purpose of the study is to provide estimation of various hydrodynamic forces acting on the bare hull at different angles of operation. The operating range of velocity of the vehicle is 0-6 knot (0-3 m/s), considering up to 2 knots of upstream current. For the purpose of the CFD simulation, the widely-implemented RANS approach is used, wherein the turbulent transport equations are solved using the low- Re version of the SST ?-? turbulence model. The motion of the vehicle is considered within a range of the pitch angle (0<=alpha<=20). The results are presented in terms of variations of the relevant hydrodynamic parameters. The effects of the angle of attack on the drag and pressure coefficients are discussed in detail.","PeriodicalId":55961,"journal":{"name":"Journal of Naval Architecture and Marine Engineering","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2016-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3329/JNAME.V13I2.25849","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69515466","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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