Journal of Naval Architecture and Marine Engineering

Numerical investigation of 3-D wing moving over free surface in water of finite depth

2024-02-27T16:55:49+00:00

Three-dimensional (3-D) wing moving steadily over free water surface with the effects of finite depth has been investigated numerically by an iterative boundary element method (IBEM) developed originally before for cavitating 3-D hydrofoils advancing under free surface. The IBEM has been modified and extended to do this. The fluid is assumed inviscid, incompressible and the flow irrotational. All variables and equations are made non-dimensional. In this way the convergence of numerical scheme is achieved very quickly and consistently. The IBEM is based on the Green’s theorem. The wing problem (including its wake), the free surface problem and the bottom surface problem are solved separately with the effects of each other via their potential values. The 3-D wing surface, the free surface and bottom surface are modeled with constant strength source and constant strength doublet panels. The kinematic boundary condition is applied both on the wing surface and on the bottom surface. On the other hand, the linearized kinematic and dynamic combined condition is applied on the free water surface. The method is first applied to a rectangular wing with a high aspect ratio to compare the pressure distribution on mid-section strip with that of two-dimensional method. Later, the IBEM is applied to a tapered swept-back wing and the effects of finite depth on wing performance have been investigated. It is found that the shallower water depth caused an increase in Kelvin wedge angle, wave height and wave length as compared with in infinite depth case. It is also found that a decrease depth of bottom surface is caused an increase in loading on the wing.

Journal of Naval Architecture and Marine Engineering, 21(1), 2024, P: 1- 14

Impact of MHD and nanofluid flow-through a vertical plate with varying heat and mass flux

2024-06-16T16:45:52+00:00

An investigation is made to discuss the effects of Magnetohydrodynamic and nanofluid particles on unstable two-dimensional free convective flow through a vertical plate in the existence of thermal source, radiation effect, and chemical reaction effect with varying thermal and mass flux. The guiding unsteady equations were cracked using the implied finite-difference method. Here we considered four dissimilar nanofluids including Cu, Al₂O₃, TiO₂, and Ag with water as base fluid. The flow pattern employed incorporates the result of dissimilar non-dimensional parameters for instance volume fraction, magnetic field, heat source parameter, Prandtl number, radiation effect, Schmidt number, and chemical reaction effect. The impacts of the above-mentioned parameters on the boundary layer flow characteristics (velocity, temperature, concentration, skin friction coefficient, Nusselt number, and Sherwood number) are intentional. The impact of the velocity profile is highest in silver-water nanofluids and lowest in Al₂O₃water nanofluids among the nanofluids considered in this study but the reverse trend is observed with respect to temperature. Moreover, the outcomes are explained through graphs.

Journal of Naval Architecture and Marine Engineering, 21(1), 2024, P: 15- 26

Analytic study of Soret and Dufour effects on heat destructive Casson liquid movement past an infinite vertical plate

2023-10-18T17:12:41+00:00

This article describes a scientific solution of an unsteady movement of a Casson liquid in an infinite vertical plate in the proxy mity of Soret and Dufour implementations. The non-dimensional structure of mathematical equations is integrated with convenient initial and boundary limitations by applying Laplace transform technique. The expressions for Casson liquid motion, temperature, concentration, Skin-friction, heat and mass transfer coefficients are displayed. In the course of discussions, the effects of main parameters are described. The liquid motion, temperature, and concentration profiles are presented graphically for Pr = 1 and Sc = 0.22 as well as for arbitrary values of other parameters. The study is significant in the application areas of chemical analysis and biological analysis, drug delivery, bacteria detection and some others. A comparative analysis of the current research with previously published work is presented.

Journal of Naval Architecture and Marine Engineering, 21 (1), 2024, pp. 27–40

Exact solution for couple stress fluid flow past a fluid sphere embedded in a porous medium with slip condition

2023-12-05T09:49:41+00:00

In this paper, using interfacial slip on the boundary, the exact solution is obtained for the Stokes flow through a couple stress fluid sphere which is embedded (implanted) in a porous medium. Analytical computations are derived for the stream functions and drag. For the drag force, special conditions are deduced that satisfy the literature's facts. Graphs are created and the numerical results are tabulated. It is noticed that in the external viscous fluid case the porosity parameter and the drag coefficient are directly correlated and for the external couple stress fluid case with raises in slip parameter the coefficient of drag reduces.

Journal of Naval Architecture and Marine Engineering, 21 (1), 2024, pp. 41–50

Hepatic tumor ablation using electric current and bioheat transfer model: a 3D numerical analysis

2024-06-16T16:25:32+00:00

A three-dimensional thermal-electric including a four-tiny radiofrequency probe, hepatic tissue, and an integrated model of a large blood vessel are investigated numerically. The FEM is employed in the determination of the distribution of tissue temperature during radiofrequency hepatic tumor ablation through the heated targeted cells that are supposed to kill and the healthy surrounding tissues are supposed to save. The mathematical reproduction is led for various times from 0 s to 1000 s and electric voltage from 22 V to 50 V with good convergence of the iterative scheme. In terms of temperature fields at different times, iso-surfaces with temperatures of 50°C at various times, iso-surfaces at different temperatures, and the temperature distribution over time are displayed graphically. Temperature distribution against time at the tip of one of the electrodes arms at a fixed voltage and various voltages are also demonstrated. Results from the RF simulation specify that temperature increases due to increasing time of ablation of tumor and electric voltage. The tumor cell is killed approximately at 50°C with 22 V after 480 s heating. The proposed model may be a new tool for physicians for the efficient thermal insulation of tumors without any significant damage in healthy tissues.

Journal of Naval Architecture and Marine Engineering, 21 (1), 2024, pp. 51–66

Analytical solutions of Poiseuille flow of second-grade fluid

2024-03-02T17:02:39+00:00

Poiseuille flow are considered as flows of Newtonian fluids through stationary pipes, with applications ranging from the pharmaceutical industries to manufacturing companies. These flows have been extensively studied in several works of literature due their relevance in many spheres of life. However, the Poiseuille flow for non-Newtonian flows have not gained much attention, despite the fact that most fluids are non-Newtonian. Based on this, this study investigates the Poiseuille flow of the second-grade fluid. Second-grade fluid are viscoelastic non-Newtonian fluids that exhibit both shear-thinning and shear-thickening with applications found in several industrial applications such as pharmaceutical, cosmetics and polymer processing. The Poiseuille flow of second-grade fluid is formulated from the underlying Navier-Stokes’ equations and the general assumptions of Poiseuille flow are invoked to reduce the equations to the regular ordinary differential equations. Analytical solution for the flow problem is sought using the method of separation of variables and the results are graphed to show the response of velocity and flow rate to the parameters of the flow. The outcomes show that velocity distribution reduces as the pipe radius increases and second-grade fluid have lower velocity than the Newtonian fluid.

Journal of Naval Architecture and Marine Engineering, 21(1), 2024, P: 67-77