 Subjects -> MILITARY (Total: 106 journals)
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- Design and testing of a compact inexpensive prototype remotely operated
underwater vehicle for shallow water operation
Authors: Ahsan Tanveer, Sarvat Mushtaq Ahmad
Pages: 1 - 10
Abstract: This article introduces the development of an unmanned remotely operated vehicle (ROV) that measures 35 cm x 26 cm x 23 cm and weighs 1.59 kg. The primary objective is to remotely communicate in real time using serial protocol to record the vehicle's orientation data. The three DC motors powering the ROV are controlled by a multi-parameter root-locus proportional integral (MRPL-PI) controller. Utilizing the processing capabilities of the Atmega328 microcontroller, heading, depth control, and water condition monitoring are all accomplished simultaneously. The Arduino development environment is used to establish the ROV's remote control. The problem with human divers who can only descend to a depth of 30 meters is resolved by the proposed ROV's ability to dive up to 100 meters underwater. Furthermore, the suggested vehicle can be beneficial in marine applications such as measurement, maintenance, operations, and surveillance.
PubDate: 2023-06-29
DOI: 10.3329/jname.v20i1.64301
Issue No: Vol. 20, No. 1 (2023)
- Wave overtopping characteristics of a non-perforated and seaside
perforated quarter-circle breakwater
Authors: Vishwanatha Mane, Subba Rao, Lokesha, Arkal Vittal Hegde
Pages: 11 - 23
Abstract: A breakwater is a structure used to dissipate the wave energy in order to protect the shore and maintain tranquility inside the harbor basin. The quarter-circle breakwater (QBW) constitutes of a quarter circular front wall facing incident waves, a vertical rear wall, and a horizontal base slab placed on a rubble mound foundation. In this study, a comprehensive experimental investigation is carried out in order to examine the wave overtopping characteristics of a non-perforated and seaside perforated emerged quarter-circle breakwater subjected to regular waves. A model scale of 1:30 is selected based on the limitations of testing facilities. For the current investigation, QBW models of the radius 0.50 m are utilized. The model is tested for six different perforations ranging between 0% and 20%, with a constant perforation radius of 0.016 m. The paper highlights the influence of wave steepness (Hi/gT2), relative crest freeboard (Rc/Hi), relative water depth (d/gT2) on the wave overtopping performance of the seaside perforated and non-perforated QBW models. An increase in wave steepness is found to increase the dimensionless mean wave overtopping discharge. Also, an exponential decrease in dimensionless mean wave overtopping discharge is observed with an increasing relative freeboard. The relative freeboard is found to be one of the predominant parameters influencing the wave overtopping discharge rate.
PubDate: 2023-06-30
DOI: 10.3329/jname.v20i1.55046
Issue No: Vol. 20, No. 1 (2023)
- MHD Casson and Carreau fluid flow through a porous medium with variable
thermal conductivity in the presence of suction/injection
Authors: Babitha A, Ramana Murthy Ch.V., G. V. Ramana Reddy
Pages: 25 - 35
Abstract: In this take a glance at, we have a tendency to investigated the results of hydrodynamics (MHD) Casson and Carreau fluid (CCF) heat via a porous medium at the aspect of a stretching sheet. Variable thermal physical phenomenon and suction/injection parameter results are also taken into the thought. Similarity modifications area unit applied to convert the governing equations of the CCF glide model into dimensionless non-linear normal differential equations. The answers area unit conferred through graphs and tabular type. the velocity, concentration, temperature profile, skin friction constant, and also the Nusselt and Sherwood numbers below the result of various parameters area unit studied. The fluid waft is analyzed for every suction and injection cases. From the analysis finished, it's miles discovered that the speed profile reduces via increasing the magnetic parameter. The temperature space enhances by increasing the variable thermal physical phenomenon and also the Nusselt wide selection reveals opposite behaviour
PubDate: 2023-06-30
DOI: 10.3329/jname.v20i1.61155
Issue No: Vol. 20, No. 1 (2023)
- Stress-strain analysis of structural discontinuities associated with ship
hulls
Authors: Kazi Naimul Hoque, Md. Shahidul Islam
Pages: 37 - 51
Abstract: The finite element method (FEM) is already well-established as a strong and widely used numerical analytical methodology for determining solutions to a wide variety of structural mechanics issues. One of the most significant subjects in the design of not only ships, but also airplanes and other structures is the configuration of plate type structures, particularly with discontinuities. A structural discontinuity occurs when the cross section of a structural part changes abruptly due to material defects or high stress locations. This article primarily focuses on the fundamental concepts of FEM for finding solutions of two-dimensional plane stress and plane strain problems to evaluate stresses such as normal stress, shear stress, and von-mises stress at the four integration points (gauss points) for various sections of ship structures (especially at the most vulnerable areas), such as plate with holes, plate with bracket and holes, and plate with fillets. To study structural discontinuity problems for various ship structures, an object-oriented programming method is used to create a finite element program for four node quadrilateral elements. With the aid of commercial finite element analysis software, the analysis findings of gauss point stresses for different ship sections produced from the developed program are validated.
PubDate: 2023-06-30
DOI: 10.3329/jname.v20i1.58298
Issue No: Vol. 20, No. 1 (2023)
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