Defence Science Journal最新文献

{"title":"Aerodynamic Investigation of Blended Wing Body Configuration","authors":"Midhun MV, Partha Mondal, Pawan Kumar Karn, Priyank Kumar","doi":"10.14429/dsj.73.17735","DOIUrl":"https://doi.org/10.14429/dsj.73.17735","url":null,"abstract":"
 A blended wing body (BWB) configuration is an unconventional aircraft design in which the wing and fuselage are blended to form an aircraft. This design concept has inherent higher aerodynamic efficiency, environmental benefits and capacities. These advantages make the BWB configuration a feasible concept for commercial transport aircraft. In the present work, a 3-D BWB model is designed in SolidWorks and fabricated using a 3D printer. The numerical and experimental analyses are carried out with this BWB geometry. Aerodynamic characteristics and flow features obtained from the open-source CFD software OpenFOAM have been studied, analyzed, and compared with the wind tunnel results. Experimental and computational data compare well and the present BWB can operate at a high angle of attack. The coefficient of lift (CL) increases with AoA up to 45º. The CL starts decreasing beyond this AoA, and the present BWB geometry stalls at around AoA = 45º. The coefficient of drag (CD) increases with the increase in AoA due to the spreading of the separated region over the geometry. Lift/Drag (L/D) variation with AoA is also studied to find the optimum flight configuration of the present BWB geometry. Sectional pressure distribution at different spanwise locations, velocity contours, pathlines, surface limiting streamlines and tuft flow visualization are also presented to investigate the flow. The studies investigate the aerodynamics, flow field and optimal flight configuration for cruising a BWB geometry.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developing Successful Commercialisation Model Through Technology Transfer Assessing its Validity and Reliability by Using Structural Equation Modelling","authors":"S. Sudha Rani, B. Madhusudan Rao, Prahlada Ramarao","doi":"10.14429/dsj.73.18578","DOIUrl":"https://doi.org/10.14429/dsj.73.18578","url":null,"abstract":"The aim of this research is to develop and validate a suitable structural model for commercialization of successful innovations/ideas/methodology of R&D organizations through technology transfer. The survey data was extracted from 231 responses out of 310 target participants against the structured questionnaire containing 60 questions designed based on the literature survey. The factor structure and preliminary model are evaluated through Exploratory Factor Analysis. The first order and higher order Confirmatory Factor Analysis(CFA) models are evolved by estimating coefficients, covariance matrix, variances and performance indices. Structural Equation Modelling (SEM) is employed to develop and assess the validity and reliability of the structural model. The results implied that the developed structural model has achieved the required level of metrics and it can be implemented in to R&D organizations and industries for successful commercialization.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Novel Goal oriented Sampling Method for Improving the Convergence Rate of Sampling based Path Planning for Autonomous Mobile Robot Navigation","authors":"Sivasankar Ganesan, Senthil Kumar Natarajan, Asokan Thondiyath","doi":"10.14429/dsj.73.17888","DOIUrl":"https://doi.org/10.14429/dsj.73.17888","url":null,"abstract":"Autonomous Mobile Robots' performance relies on intelligent motion planning algorithms. In autonomous mobile robots, sampling-based path-planning algorithms are widely used. One of the efficient sampling-based path planning algorithms is the Rapidly Exploring Random Tree (RRT). However, the solution provided by RRT is suboptimal. An RRT extension known as RRT* is optimal, but it takes time to converge. To improve the RRT* slow convergence problem, a goal-oriented sampling-based RRT* algorithm known as GS-RRT* is proposed in this paper. The focus of the proposed research work is to reduce unwanted sample exploration and solve the slow convergence problem of RRT* by taking more samples in the vicinity of the goal region. The proposed research work is validated in three different environments with a map size of 384*384 and compared to the existing algorithms: RRT, Goal-directed RRT(G-RRT), RRT*, and Informed-RRT*. The proposed research work is compared with existing algorithms using four metrics: path length, time to find the solution, the number of nodes visited, and the convergence rate. The validation is done in the Gazebo Simulation and on a TurtleBot3 mobile robot using the Robotics Operating System (ROS). The numerical findings show that the proposed research work improves the convergence rate by an average of 33% over RRT* and 27% over Informed RRT*, and the node exploration is 26% better than RRT* and 20% better than Informed RRT*.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ethernet Over Coaxial (EoC) Cable Telemetry Over High Voltage Dc And High Power Ac For Airborne Sonar Applications","authors":"Manoj G., R. Ramesh, Sona O. Kundukulam","doi":"10.14429/dsj.73.18456","DOIUrl":"https://doi.org/10.14429/dsj.73.18456","url":null,"abstract":"
 
 
 We have proposed a new passive component-based coupling scheme to simultaneously transmit high power AC, high voltage DC and high speed data through a long, single core coaxial cable, particularly for Airborne Sonar applications. This method is intended to replace the bulky multicore cables with single core coaxial cables that are compact and effective for transmitting data over long distances. This coupling scheme consists of three couplers to superimpose high power AC, high voltage DC and high speed data at the onboard end of the cable, and three decouplers to separate them at the remote end. The long cable, couplers, decouplers and the acoustic transducer are represented by their corresponding equivalent circuits that are cascaded together to construct the complete network. Power loss in the circuit is minimised by providing impedance matching networks in the form of a T-network transmission line and a tuning coil. The Ethernet over Coaxial (EoC) module can transmit high speed Ethernet data at the rate of 10/100 Mbps for telemetry from onboard to remote units and vice versa. DC voltages up to 300 V are coupled to the single core coaxial cable from the onboard unit and superimposed with high power AC signals and high-speed data. Passive filter-based coupling and decoupling schemes are demonstrated. Network simulation studies and experimental studies are carried out to verify and validate the equivalent circuit model. The transfer functions of each set of couplers and decouplers are determined independently as well as collectively and their effects on the underwater acoustic performance of the system are studied. The model resuls are found to agree with experiments. The proposed system is capable of generating an acoustic Source Level of about 195 dB with the supply of 125 V continuous wave (CW) AC signals, with simultaneous transmission of data at 10 Mbps and DC supply of 260 V from the on-board unit to the remote unit at the end of a coaxial cable of 200 m length. Introduction of impedance matching network is found to increase the source level by about 12 dB.
 
 
","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of Explosion Crater of Earth Penetrating Nuclear Bomb Based on Equivalency to TNT Mass","authors":"Liangquan Wang, Deren Kong, Fei Shang, Chuyang Zhang","doi":"10.14429/dsj.73.18618","DOIUrl":"https://doi.org/10.14429/dsj.73.18618","url":null,"abstract":"
 
 
 The structure size of the crater formed by the earth-penetrating nuclear bomb explosion is one of the important parameters for evaluating the earth-penetrating nuclear bomb damage power. Obtaining the structure size of the crater formed by the earth-penetrating nuclear bomb explosion with different yields is great significance for the evaluation and design of the nuclear bomb damage power. In this study, considering the contradictory relationship between the structure size of the earth-penetrating nuclear bomb and the structure size of the equivalent TNT mass, we propose to use the equivalent energy mapping method to realize the finite element numerical simulation of the earth-penetrating nuclear bomb exploding into craters analyzed and compared the simulation results with the structure size of the crater formed by the ESS nuclear bomb explosion in the United States. The analysis results show that the error between the simulated crater radius and the real crater radius is 3.26%, and the error between the simulated crater depth and the real crater depth is 28.57 %. It meets the calculation accuracy error range of crater formation from nuclear explosion to chemical explosion. Therefore, this method provides an effective numerical simulation method and a means of obtaining the structural size data of the explosion crater for the earth-penetrating nuclear bomb cratering.
 
 
","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studies of Jet A1 Fuel Atomization Through Non Circular Orifices","authors":"V. Vani Pooja, Rajiv Kumar","doi":"10.14429/dsj.73.17893","DOIUrl":"https://doi.org/10.14429/dsj.73.17893","url":null,"abstract":"
 
 
 The performance of the liquid rocket engine depends on the atomization behavior of the fluid being injected into the combustion chamber. Generally, a plain injector with a circular orifice has been used in the injector, but it has the disadvantage of having a low spray cone angle. The breakup length, mean droplet diameter, and Sauter mean diameter is also higher. Thus, to overcome these drawbacks, non-circular orifices have been utilized in the present study. The shapes used for non-circular orifices are semi-circular and plus. The results obtained with the non-circular orifice is compared with the circular orifices of the same area ratio. The working fluid used for the studies is Jet A1 fuel. Studies were also conducted with different L/D ratios by choosing an effective orifice length to reduce the upstream losses. The axis-switching phenomena were observed with the semi-circular as well as with the plus jets. The mean droplet size of the circular jets was more prominent compared to non-circular jets, and the Sauter mean diameter of non-circular jets droplets was smaller than that of the circular jet droplet. The spray cone angle has increased by 290% for plus jets and 30% for semi-circular jets compared to circular jets.
 
 
","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of Trajectory of High speed Artillery Shell","authors":"Manoj Sharma, Subrat Kar","doi":"10.14429/dsj.73.18342","DOIUrl":"https://doi.org/10.14429/dsj.73.18342","url":null,"abstract":"
 
 
 This paper presents a novel technique that uses the stereoscopic arrangement of multiple cameras to determine the trajectory of a high-speed projectile. It can be used to detect and track artillery shells moving at high speed in the air toward friendly territory. A system with the proposed concept can enhance retaliation success in battlefield countermeasures. There are many state-of-the-art Radar-based systems to detect moving artillery shells and mortars, but the cost and size of those products make them not so easily deployable in all kinds of terrains. A system with multiple cameras is discussed in this paper as an alternative solution. The experimental results, after algorithms were applied to simulated videos of expected scenes showed that the proposed technique is feasible. The proposed technique is fast and accurate and can be converted into deployable hardware. It can lead to realizing a system that has utility in saving precious lives in critical circumstances.
 
 
","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Development of a Laser Warning Sensor Prototype for Airborne Application","authors":"Tutul Gogoi, Rajni Kumar","doi":"10.14429/dsj.73.18662","DOIUrl":"https://doi.org/10.14429/dsj.73.18662","url":null,"abstract":"
 
 
 Due to recent developments in high-energy laser systems, the laser is becoming one of the most potential choices in battlefield applications. Laser of a laser range finder used to find target distance may be of nanosecond pulse width and a single pulse may be sufficient to gather the instantaneous range information. A laser target designator is a similar laser with higher energy and with programmable pulse repetition frequencies5,7. Detection of such a specific battlefield laser radiation along with recognizing friend or foe is required for countermeasures. Designing a laser detection system that is capable of detecting such low-power level laser pulses of nanosecond pulse width at a long distance is a critical design and a challenging task. Again detecting a wide wavelength band that can start from 500 nm to around 1700 nm range using a single detector or device is also a challenging task. In this work, a sensor system is being designed and a prototype is developed to cover such a long band detection using a single detector for high-energy lasers. Also, in addition to detecting hostile code, the direction of an incoming laser beam is tried to incorporate into this sensor. The sensor can be utilized to detect unknown or non-friendly laser illumination from within a specific angular cone and distance.
 
 
","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Comparative Study on various Flight Termination System Technologies","authors":"Sushree Priyadarshini, Mohapatra Kumar Gourab, Utpal Mandal, Angshuman Roy","doi":"10.14429/dsj.73.18334","DOIUrl":"https://doi.org/10.14429/dsj.73.18334","url":null,"abstract":"In a test range, a Flight Termination System (FTS) plays a prominent role in protecting range and flight personnel along with surrounding area population in case the flight vehicle is out of its trajectory range and possesses a threat to surrounding. An efficient FTS should posses high Signal to Noise Ratio, link robustness to ensure reliable communication between ground transmitting and onboard receiving systems and should be immune to interference. This article presents a detailed report on the requirement and features of FTS & technologies used in it. Techniques such as tone based, code based and Code Division Multiple Access (CDMA) are considered. Analysis of RF spectrum, gain and noise figure measurement and channel power are presented. Advanced methods like Enhanced Flight Termination System (EFTS) and Autonomous Flight Termination System (AFTS) are considered which show supportable and upgradable technologies, better range understanding, unique vehicle id & higher data rate. AFTS being self-reliant provides superior performance in terms of GPS, launch responsiveness, multiple flight vehicle control and auto pilot.","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on dynamic mechanical properties of projectile 155mm ERFB BT material","authors":"Rajesh B. Ohol, Tekram N. Parshuramkar, B. A. Parate, Dineshsingh G. Thakur","doi":"10.14429/dsj.73.18644","DOIUrl":"https://doi.org/10.14429/dsj.73.18644","url":null,"abstract":"Artillery projectile 155mm high explosive (HE) extended range full bore boat tail (ERFB BT) and its components experience a high pressure loading of the propellant during gun launch. Mechanical properties of an engineering material are measured using quasi-static tensile test at room temperature. The materials of the projectile and its components are expected to survive time dependent propellant pressure loading inside the gun, which lasts for few microseconds. To investigate dynamic mechanical properties of the projectile and its components at medium strain rates and elevated temperature, the experimental analysis is undertaken. This research paper aims to examine the effect of medium strain rates and elevated temperatures on flow properties of the materials used in the projectile. The uniaxial tensile tests at the medium strain rates between 0.01 s-1 to 1s-1 and at elevated temperatures ranging between 150°C to 500°C are performed separately. The Considѐre criterion was applied to evaluate strain hardening exponent of the materials. Values of strain hardening exponents of shell body and boat tail materials are less than that of driving band material. Strain rate sensitivity of the materials is observed to be very low, thus indicating a good resistance to plastic deformation. The yield strength and true yield strength of the materials fall with increase in temperature.
 
","PeriodicalId":11043,"journal":{"name":"Defence Science Journal","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135421703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}