Defence Research and Development Laboratory

About: Defence Research and Development Laboratory is a facility organization based out in Hyderabad, India. It is known for research contribution in the topics: Turbulence & Mach number. The organization has 404 authors who have published 420 publications receiving 4183 citations. The organization is also known as: DRDL.

Comparative study of middleware for C4I systems Web Services vis-à-vis Data Distribution Service

Abstract: The Command, Control, Communications, Computer and Intelligence (C4I) systems provide battlefield information for the commanders to make decisions, and to control the military forces to accomplish missions. These systems were based on static architectures to ensure high dependability, support for real-time constraints and were mission specific. However, these systems lacked the dynamic features provided by recent advances in information technology. C4I systems require that both the feature sets of static and dynamic approaches be made available to ensure dependability, real-time support, facilitating reusability and interoperability. Web Services based on the Service Oriented Architecture (SOA) is the most popular middleware used in Enterprises today. Another middleware which is becoming popular is Data Distribution Service (DDS) based on Data-Centric Publish Subscribe Infrastructure. Recent advances in both the approaches have made them competitive for implementation in C4I systems for integrating its elements. Both the approaches need to be evaluated considering the system requirements of military communications. This paper carries out a comparative study of the two middleware solutions for integrating C4I system of a weapon system deployed in modern battlefields. In this paper, we present possible solutions and remaining challenges on the way towards realizing seamless information exchange for a weapon system.

Evaluation of Kerosene Fuelled Scramjet Combustor using a Combination of Cooled and Uncooled Struts

Abstract: The scramjet combustor a vital component of scramjet engine has been designed by employing fuel injection struts. Several experimental studies have been carried out to evaluate the propulsive performance and structural integrity of the in-stream fuel injection struts in the connect-pipe test facility. As the mission objective of hypersonic demonstrator is to flight test the scramjet engine for 20 s duration, in-stream fuel injection struts which are designed as heat sink devices encounter hostile flow field conditions especially in terms of high thermal and high convective loads in the scramjet combustor. To circumvent these adverse conditions, materials like Niobium C-103 and W-Ni-Fe alloys have been used for the construction of struts and a number of tests have been carried out to evaluate the survivability of the in-stream fuel injection struts in the scramjet combustor. The results thus obtained show that the erosion of leading edges of the Stage-II fuel injection struts in the initial phase and subsequently puncturing of the fuel injection manifold after 10-12 s of the test are noticed, while the other stages of the struts are found to be intact. This deteriorating leading edges of Stage-II struts with respect to time, affect the overall propulsive performance of the combustor. To mitigate this situation, Stage-II struts have been designed as cooled structure and other Stages of struts are designed as un-cooled structure. Material of construction of struts used is Nimonic C-263 alloy. This paper highlights the results of the static test of the scramjet combustor, which has been carried out at a combustor entry Mach number of 2.0, total temperature of 2000 K, with an overall kerosene fuel equivalence ratio of 1.0 and for the supersonic combustion duration of 20 s. Low back pressure has been created at the exit of the scramjet combustor using ejector system to avoid flow separation.Visual inspection of the fuel injection struts after the test revealed that all the Struts are found to be thermo-structurally safe in the combustor environment except for minor erosion of the leading edges of the struts. Stage-II struts made of two-passage cooled configuration are found to be thermo-structurally safe. Although other stages of struts used in the test are of un-cooled configuration, they too are found to be safe and intact. This demonstrates the fact that they experience thermally benign flow conditions compared to Stage-II struts in the scramjet combustor. Defence Science Journal, 2014, 64(1), DOI:http://dx.doi.org/10.14429/dsj.64.2733

Experimental Investigations and Development of cutting force model for Self Propelled Rotary Face Milling Cutter in Machining of Titanium Alloy

Abstract: In self-propelled rotary tool machining, a circular cutting tool insert is used that continuously rotates about its axis during machining, as the tool is fed into the workpiece. The continuous rotation of the insert allows the insert to cool between engagements and improves tool life. In order to make use of this methodology for rough machining and bulk material removal in machining of aerospace materials, a self-propelled rotary face milling cutter is developed at Defence Research and Development Laboratory, Hyderabad. This cutter was developed to study the influence of inclination angle on the cutting forces generated during machining, and hence the cutter is provided with the provision to have the inclination angle of the insert for 20°, 30°, 40° and 50°. This article discusses the performance of the developed self-propelled rotary face milling cutter in face milling of titanium alloy at different inclination angles. The cutting forces developed in FX, FY and FZ directions are evaluated at different cu...

Parallelisation of a Gridfree Kinetic Upwind Solver

Abstract: A gridfree Euler code has been parallelised on Single Program Multiple Data (SPMD) architecture. Parallelisation of a gridfree code involves domain decomposition, datastructure for communication and communication of data across processors. In this paper, strategies followed to accomplish the above tasks to parallelise a gridfree Euler code have been discussed. The performance of gridfree Euler code on cluster computer has been brought out for supersonic flow past hemisphere and complex flight vehicle with fin deflection test cases. 1 is a gridfree method which requires just a distribution of points in the computational domain and a set of neighbours, called connectivity, around each point. The above method does not require complex grid generation effort to solve the governing equations of fluid dynamics. Therefore, it reduces considerably grid generation time and also makes it possible to obtain solutions for the geometrically complex configurations. A 3-D gridfree Euler code based on q-LSKUM has been developed and the code has been thoroughly verified, validated and applied to a number of practical configurations including multi-body configurations 1 . Even though, the gridfree q-LSKUM reduces grid generation time for CFD analysis, the CFD simulation of flow past practical flight vehicles require considerable CPU time for each flow condition. In order to reduce the time-to-solution, high performance CFD computations for large-scale realistic applications must be performed efficiently on state-of-the-art parallel supercomputers. Parallelisation of gridfree codes has the advantage that load balancing and communication between processors are to be dealt with single type of entity, namely, points irrespective of complexity of the problem to be solved. In the present work, parallelisation strategies adopted for gridfree solvers to run on Single Program Multiple Data (SPMD) computing platforms are addressed. In SPMD architecture, the complete domain is decomposed into sub-domains and each subdomain is loaded into each processor. Each processor solves the governing equations within its sub-domain and necessary values from other sub-domains are obtained through message passing using MPI libraries. E