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  Subjects -> MILITARY (Total: 106 journals)
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Journal of Naval Architecture and Marine Engineering
Journal Prestige (SJR): 0.323
Citation Impact (citeScore): 1
Number of Followers: 5  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1813-8535 - ISSN (Online) 2070-8998
Published by Bangladesh Journals Online Homepage  [88 journals]
  • Numerical study on the cavitation noise of marine skew propellers

    • Authors: Agung Purwana, I. Made Ariana, Wisnu Wardhana
      Pages: 97 - 107
      Abstract: In this study, numerical simulations on the noise of the underwater marine propeller for different pressures, skew angles, and performance conditions are investigated. The study has been carried out for the prediction of cavity and noise cavitation characteristics of the propeller. The blade sheet cavitation created by an underwater propeller is then evaluated using numerical analysis. The cavitation and cavity around marine propellers were predicted using MRF (Multiple Reference Frame) techniques. The simulation uses the Reynolds Averaged Navier-Stokes (RANS) formulation with the turbulence model k-ω Shear Stress Transport and the Fast Fourier Transform. The FW-H equation is used to measure far-field radiation under various operating conditions. The simulation is carried out to present that the pressure and skew propeller angles have an effect on the form and area of the cavity, as well as cavitation noise. The noise characteristics at various positions of hydrophones and speeds of the marine propeller are presented. The 3D model of B-series marine propeller with D=250 mm, Z=4, P/D= 1.0, AE/AO=0.55, skew angles of 16, 35, 53, and 72 degrees at advance coefficient, J=0.221, is used for the simulation
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.38099
      Issue No: Vol. 18, No. 2 (2021)
  • A new approach to determining heating parameters suitable for hull plate
           forming by torch line heating

    • Authors: Thai Gia Tran, Viet T. Doan
      Pages: 109 - 125
      Abstract: In shipbuilding, the process of forming flat metal plate into curved hull plates with compound shapes is very important and has greatly affected many economic and technical factors such as strength, quality, and aesthetics of the hull, construction cost and time, etc. Currently, the forming method of curved hull plates by line heating is used effectively and commonly in many shipyards, however, its main problem is very difficult to determine where and how much to heat on the flat metal plate to obtain the plate of a certain shape. In this article, a finite element model is established and adjusted based on the actual data to numerical simulate the process of forming hull plates by using flame torch line heating. Base on this, the suitable position and temperature for the heating lines in the forming process are determined to form a metal plate into hull plates with the exact desired shapes. This research has been applied for forming by torch line heating of two plates, denoted K1 and K10, in the bulb bow of a 20,000 DWT cargo ship, built at Camranh Shipyard in Vietnam with the deformation deviations between the actual and desired plate surfaces are within ± 3%.   
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.51412
      Issue No: Vol. 18, No. 2 (2021)
  • A study for validating, rectifying and optimizing the flow in the test
           section of a circulating water channel

    • Authors: Kiran George Varghese, Vinay Gopi Nair, Avinash Godey, P. G. Sunil Kumar
      Pages: 127 - 140
      Abstract: The Circulation Water Channel (CWC) is an experimental facility available at Indian Maritime University, Visakhapatnam Campus. A study for comparing the flow pattern and velocity in the test section, for different configurations of the CWC, is complex. To study the flow, a physical model of the CWC, with different configurations, should be made, which in overall is a complicated and time-consuming exercise. But this difficulty can be overcome through using Computational Fluid Dynamics (CFD) analysis, as in this study, where a CFD analysis is done using ‘STAR-CCM+’ software. A CFD model of the existing CWC [corresponding to the 1:4 scale setup at IMUV], is first made, and its validity is checked, by comparing the results of the CFD analysis, against those results obtained from the experimental analysis. On successfully validating the results, modifications are suggested for rectifying the disturbance which is present in the test section. The test section is the area in the CWC where experimental activities are carried out. In order to carry out the experiments with a certain degree of accuracy, it is important to have a smooth streamlined flow in the test section. To ensure this, a honeycomb structure is positioned such that the flow enters the test section through the honeycomb, which streamlines the flow. On successfully rectifying the disturbance, studies are carried out to improve the streamlined flow in the test section, for which, different configurations of honeycomb structure are studied. The optimum honeycomb structure, which produces a smooth flow in the test section of a CWC is found out, by conducting analyses for different shapes - i.e. for shapes ranging from rectangular to hexagonal and circular, against different inlet velocities. The present paper sums up the findings of our earlier research, ‘CFD as a Tool to Validate and Modify the Flow in the Test Section of a Circulating Water Channel’, and ‘Study of Flow in the Test Section of a Circulating Water Channel by Varying the Honey Comb Cross Section’, which were published in the conference proceedings of Indian Institute of Technology, Madras, and Indian Maritime University, Visakhapatnam, respectively.
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.45982
      Issue No: Vol. 18, No. 2 (2021)
  • Hydrodynamic performances of a wall type breakwater - a physical and
           numerical approach

    • Authors: Kumaran Viswanathan, Manu, Subba Rao
      Pages: 141 - 154
      Abstract: In this paper, hydrodynamic characteristics of caisson type breakwater are investigated through physical model approach and a numerical model based on the Volume of Fluid (VOF) is validated. The investigations are carried out for varying wave characteristics and depth of water 0.50 m. In an experimental study, to understand the model and scale effects for the desired wave conditions is a critical task in all-time conditions. So, it is also necessary to develop an appropriate numerical model to understand the hydrodynamics of the selected test model. Using the Volume of Fluid (VOF) method and incompressible open channel fluid flow a 2D numerical wave flume is developed using ANSYS- Fluent platform. The wave boundary conditions are adopted by solving the Reynolds-Averaged Navier Stokes equations (RANS equation) and especially with k—ε model to examine the effects of turbulence on the numerical results. The wave forces, wave runup, and wave reflection characteristics on the test model are measured for different wave characteristics, and results obtained from the numerical investigations are comparable with the experimental results to evident the relevance of the developed numerical model.
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.52134
      Issue No: Vol. 18, No. 2 (2021)
  • Effect of aneurysmatic artery on blood flow having permeability in human

    • Authors: Md. Nasir Uddin, Md. Abdul Alim, Md. Mashud Karim, Md. Monjarul Alam
      Pages: 155 - 173
      Abstract:  Blood flow in a double aneurysmatic artery of the normal tissue is studied. A Finite Element method is used to analyze numerical simulation of blood flow through aneurysmatic arteries. The Newtonian, generalized Newtonian, Oldroyd-B and generalized Oldroyd-B models are considered due to the behavior of blood viscosity. In this paper, the effect of aneurysmatic artery on blood flow with permeability in human organ has been investigated. The non-Newtonian models have been applied to study the blood velocity, pressure, and wall shear stress in an aneurysmatic artery. A set of partial differential equations are transformed into dimensionless equations using non-dimensional variables and solved numerically. We have focused our consideration on the simulation of blood velocity and pressure in terms of blood flow rate for various Weissenberg numbers (Wi) and Peclet numbers (Pe). The important effects on blood flow of aneursymatic artery for blood velocity, pressure and wall stress profiles are presented graphically for Newtonian and non-Newtonian models.          
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.53624
      Issue No: Vol. 18, No. 2 (2021)
  • Effect of Joule heating on steady MHD convective micropolar fluid over a
           stretching/shrinking sheet with slip flow model

    • Authors: A.P. Baitharu, Sachidananda Sahoo, G.C. Dash
      Pages: 175 - 186
      Abstract: The effect of joule heating on steady two dimensional flow of an incompressible micropolar fluid over a flat deformable sheet is analyzed when the sheet is stretched with a slip in its own plane. The effects of first and second order slips with dissipative heat energy are considered in the present study. The numerical solution to coupled non-linear differential equations is obtained using the Runge-Kutta method of fourth order with shooting technique. The important findings of the present study are: Due to shrinking effect, temperature increases more than that of stretching which is analogous to contraction and expansion forming the basis of heat engine, transporting thermal energy to mechanical energy. The thermal buoyancy overpowers the inertia force. The second order slip is favorable for flow stability in both stretching and shrinking of the deformable surface.
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.55253
      Issue No: Vol. 18, No. 2 (2021)
  • A computational study on flow characteristics and energy distribution in a
           rotating coiled rectangular duct with longitudinal vortex generation

    • Authors: Ratan Kumar Chanda, Mohammad Sanjeed Hasan, Md. Mahmud Alam, Rabindra Nath Mondal
      Pages: 187 - 205
      Abstract: Investigation on fluid flow and energy distribution in a rotating coiled rectangular duct (CRD) with differentially heated horizontal walls has been analyzed numerically by using a spectral-based numerical scheme. The system is rotated around the vertical axis in the clockwise direction over the Taylor number (Tr) ranging from 0 to 2000 keeping the other parameters constant as aspect ratio Ar =3, curvature ratio BETA=0.5 the Dean number Dn = 1000 and the Prandtl number Pr = 7.0 (water). To reveal steady solution (SS) curves, we applied path continuation technique and obtained five asymmetric SS curves comprising with 2- to 8-pair cell. A bar diagram is also drawn to visualize, at a glance, longitudinal vortex generation on various curves of steady solutions. To explore unsteady behavior, time-progression analysis is performed and flow characteristics are precisely determined by obtaining phase space trajectory of the solutions. The transient flow demonstrates various stages of physically realizable solutions including chaotic, multi-periodic, periodic and steady-state; and it is found that the number of secondary vortices declines as Tr is increased. Convective heat transfer (CHT) is computed and the corresponding dependence on the flow stages is discussed accurately. Finally, a comparison has been made between the numerical computation and experimental investigations which shows a benchmark agreement.  
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.51972
      Issue No: Vol. 18, No. 2 (2021)
  • Topology optimization of an oil tanker bulkhead subjected to hydrostatic

    • Authors: Md. Shahidul Islam, S. C. Paul
      Pages: 207 - 215
      Abstract: In the field of Naval Architecture, the conventional approach to design any vessel is to follow the classification societies’ rules to ensure adequate strength and structural integrity. Nowadays, owners’ demands and purposes of vessels are changing dramatically. To mitigate these demands, sometimes it is necessary to design new types of structures, but the classification society’s rules are not sufficient to prepare these advanced designs. Moreover, Naval Architects are always eager to minimize the lightweight of a vessel as this is directly related to cost and carrying capacity. Topology optimization has become a powerful tool for designing structures in an optimized way. The concept of topology optimization has been utilized by the automotive and aerospace industry for almost thirty years where problems associated with solutions meant to satisfy maximum stiffness and structural integrity with minimum weight which are of utmost importance. However, in the field of marine and offshore structures, the use of topology optimization is infrequent. As structural optimization aims to design structures under certain constraints to achieve better strength and lower cost, the introduction of this technique in ship structure can be lucrative. In this paper, a methodology to apply structural topology optimization in the field of ship design is presented. An Oil Tanker Bulkhead has been selected for this study. SIMULIA ABAQUS software is used in this regard. Topology optimization has been performed by minimizing the strain energy of the component as the objective function and a target stiffness and material volume of the structure as design constraints. Finally, the results demonstrate the general applicability of the methodology presented for obtaining the geometrical layout of the structure.
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.52224
      Issue No: Vol. 18, No. 2 (2021)
  • Numerical modeling of Buongiorno’s nanofluid on free convection:
           thermophoresis and Brownian effects

    • Authors: Shatay Khatun, Rehena Nasrin
      Pages: 217 - 239
      Abstract: In this research, numerical modeling is conducted on free convective flow inside a trapezoidal domain with sinusoidal material and temperature allocations at both inclined boundaries using Buongiorno’s nanofluid. The model considers thermophoresis with Brownian activity effects taking place in the flow, temperature as well as concentration contours. Non-uniform nanoparticle solid concentration and temperature allocations have been imposed at both inclined surfaces. Top and bottom parallel surfaces have been kept as adiabatic. All the walls have been considered as no-slip and impermeable. The leading equations in addition border conditions are initially converted into a dimensionless pattern by a suitable similarity transformation and then resolved arithmetically employing the finite element technique with Galerkin’s residual. Buongiorno’s model of nanofluid on thermal and material transports, and flow structure has been investigated in detail. Outcomes have been displayed in the form of velocity, temperature, and concentration contours with various governing factors like Brownian action, Lewis number, Buoyancy relation, thermophoresis, Rayleigh number, Prandtl number, etc. Also, the rate of thermal transport has been calculated. The thermophoresis and Brownian effects on velocity, heat, and material fields are identified and finally, the flow, heat, and concentration controlling parameters for a specific material and thermal transport applications inside a trapezium-shaped cavity are obtained. Result demonstrates that the increase of Brownian action guides to enhance thermal transport by 34.75 and 34.27% for the right and left walls, respectively.
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.54694
      Issue No: Vol. 18, No. 2 (2021)
  • CFD investigation into resistance characteristics of a pusher-barge system
           in calm water

    • Authors: Ahmad - Fitriadhy, Nur Amira Adam, Izzati Pison, Mohd Asamudin A. Rahman, Mohd Azlan Musa, Mohd Hairil Mohd
      Pages: 241 - 254
      Abstract: Prediction of ship’s total resistance of a pusher-barge system has become enormous complexity involving nonlinear-hydrodynamic flows behaviour along their hull forms. Both of empirical and simplified numerical solutions may still lead into inaccurate results due to presence of nonlinear characteristics of the pressure and viscous resistances. The use of a more sophisticated method would obviously necessitate to solve the above problem. This paper presents a Computational Fluid Dynamics (CFD) approach to predict the total ship’s resistance of a pusher-barge system at various barge’s configurations. To achieve such objective, four different configurations of the barge models incorporated with various Froude numbers have been taken into account in the computational simulation. In general, the results revealed that the increase of Froude number (Fr = 0.182 to 0.312) was proportional to the magnitude of RT, RP and RV. Regardless of the various Froude number, the pusher-barge system with a 13BP configuration provides the highest resistance compared to the 12BP and 11BP. In addition, the arrangement of barges in the longitudinal (12BP) and lateral (21BP) configurations produced a significant effect with increases in RT, RP and RV values of 110%, 167.5% and 77.6%, respectively. The possible reason for this is that the increase of the total wetted surface area for 21BP has produced to a proportionally higher amount of the pressure and viscous resistance. Overall study, the numerical results were presented and analysed based on few aspects involved the total resistance and resistance coefficient in terms of pressure and viscous resistance of the pusher-barge system. This analysis provides very valuable information on choosing the most reliable arrangement of pusher-barge system. This analysis provides very valuable information on choosing the most reliable arrangement of pusher-barge system
      PubDate: 2021-12-31
      DOI: 10.3329/jname.v18i2.52593
      Issue No: Vol. 18, No. 2 (2021)
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