Journal of Naval Architecture and Marine Engineering 2020-02-21T15:03:52+00:00 Prof. Dr. Md. Mashud Karim Open Journal Systems <p>An International Research Publication by the Association of Naval Architects and Marine Engineers. Full text articles available. Click <a title="Archive" href="/index.php/JNAME/issue/archive">Archives</a>&nbsp;</p> <p>JNAME is now included in the <strong>Thomson Reuters Emerging Sources Citation Index</strong> (<a title="ESCI" href=";Full=Journal%20of%20naval%20Architecture%20and%20Marine%20Engineering" target="_self">ESCI</a>) and on <a title="DOAJ" href="" target="_blank" rel="noopener">DOAJ</a>.</p> <p>Also indexed in&nbsp;<strong>SCOPUS</strong>, EBSCO, CrossRef, IndexCopernicus, Google scholars, GoogleAnalytics.</p> <div>Enlisted on DOAJ, HINARI, BanglaJOL.</div> <p><strong>The JNAME no longer accepts hardcopy submissions or email attachment. Please submit your manuscripts online. Only one manuscript as principal or co-author is allowed at a time.</strong></p> A panel method for both marine propulsion and renewable energy 2020-02-21T14:33:23+00:00 Yiyi Xu Pengfei Liu Irene Penesis Guanghua He <p>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.</p> 2019-12-19T17:21:08+00:00 ##submission.copyrightStatement## Study of a TLP motions and forces using 3D source technique 2020-02-21T14:40:39+00:00 M R Islam M M Rahaman A Kumar <p>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 and processing. But it is challenging to design precisely such type of giant structure in deep sea as 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 both the programs are compared which shows a good agreement and also validated with the published results. Comparison of heave motion with and without tether are illustrated where it can be easily understood the effect of tendon. Forces and motions prediction of TLP is emphasized which has been done precisely in the present work and 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.</p> 2019-12-25T06:17:24+00:00 ##submission.copyrightStatement## Measurement of small vessel machinery vibration induced acoustic signature levels 2020-02-21T14:48:58+00:00 GVV Pavan Kumar V V S Prasad B H Nagesh <p>Ship vibrations, airborne and underwater noise levels have always been a challenging topic from a 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 on 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.&nbsp; The vibration levels on the foundation measured the average value of 0.207 mm/s for the 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 1┬ÁPa. The response spectra indicate the peak vibration and noise levels in the lower frequency region &lt;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.</p> 2019-12-26T00:00:00+00:00 ##submission.copyrightStatement## Effects of radiation and chemical reaction on MHD flow past a vertical plate with variable temperature and mass diffusion 2020-02-21T14:59:41+00:00 U S Rajput Gaurav Kumar <p>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.</p> 2019-12-29T00:00:00+00:00 ##submission.copyrightStatement## Mixed convective hybrid nanofluid flow in lid-driven undulated cavity: effect of MHD and Joule heating 2020-02-21T15:03:52+00:00 Ishrat Zahan R Nasrin M A Alim <p>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 TiO<sub>2 </sub>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, &nbsp;TiO<sub>2 </sub>-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.</p> 2019-12-31T06:18:47+00:00 ##submission.copyrightStatement##