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Institution

Defence Research and Development Laboratory

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


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Book ChapterDOI
01 Jan 2020
TL;DR: In this article, the authors used the Lagrangian particle tracking method for kerosene droplet and single-step chemical reaction based on fast chemistry to model the combustion process inside a scramjet combustor.
Abstract: Application of CFD tools in the design and analysis of high-speed airbreathing systems is described. Three-dimensional Navier-Stokes equations are solved along with SST-k-ω turbulence model. Lagrangian particle tracking method for kerosene droplet and single-step chemical reaction based on fast chemistry is used to model kerosene–air reaction. The computational tool is extensively validated against reliable experimental data before applying to design exercise. Better insight obtained from numerical simulations about the mixing and combustion process inside the combustor has enabled the placement of fuel injection struts and the injectors to obtain optimized combustor performance and benign thermal environments for a flight-sized hydrocarbon-fuelled scramjet combustor. Computed wall pressure matches nicely with experimental data for both non-reacting and reacting flows. Computed convective heat flux obtained through well-resolved thermal boundary layer simulations is used in the thermo-structural analysis of the scramjet combustor. End-to-end simulations integrating both external (non-reacting) and internal (reacting) flow are carried out of a complete hypersonic airbreathing vehicle to obtain complete aerodynamics and propulsion parameters of the vehicle for mission design. The evaluated installed air intake performance in terms of pressure recovery and mass capture ratio matches very well with experimental data. For higher angles of attack, windward and leeward side intakes show different performances, and leeward side intake experiences subcritical operation faster. The interaction between forebody boundary layer and intake shock system causes significant spillage. The starting and unstarting characteristics of a hypersonic intake are evaluated through unsteady RANS simulations. Both started flow and unstarted flow with large pressure oscillation are captured for different Mach numbers. The use of CFD tools has reduced the dependence of experimental testing in the design of high-speed airbreathing Propulsion Systems.

1 citations

Journal ArticleDOI
01 Dec 1972
TL;DR: This paper describes two relatively simple methods, using digital circuits, of obtaining the antenna patterns using a mechanical antenna pattern genarator or a Cathode Ray Tube Photoform Function Generator.
Abstract: In Radar Simulation technique, the simulated video echo pulses are mixed with low frequency noise (clutter) and gated over the scan interval; they are also subjected to amplitude modulation in proportion with the antenna pattern envelope swept during the scan time. Conventionally, a mechanical antenna pattern genarator or a Cathode Ray Tube Photoform Function Generator is used to obtain the modulating signal. This paper describes two relatively simple methods, using digital circuits, of obtaining the antenna patterns.

1 citations

Journal ArticleDOI
TL;DR: The salient features of computer technology used by the US for this truly hi-tech war are discussed and the important lessons learnt by the use of high technology, primarily based on computers for future wars, have been presented for their applicability in the Indian context.
Abstract: Computer technology has revolutionised weapons system and hardware during the last decade 'miracle chip' has had impact in all areas of battlefield. The recent Gulf War has amply demonstrated the important role of computer technology in warfare. The best of the high technology was used during the 45 days of air battle followed by 100 hours of ground offensive. Computer and communication formed the heart of every weapon system from Tomahawk, SLAM, Scud, Patriot missile to night vision of tanks and Stealth fighters. This paper discuss the salient features of computer technology used by the US for this truly hi-tech war. the hi-tech weapon systems using computers for achieving surgical precision have been highlighted. The Indian scenario and the important lessons learnt by the use of high technology, primarily based on computers for future wars, have been presented for their applicability in the Indian context.

1 citations

Journal ArticleDOI
TL;DR: In this paper, the authors measured the decomposition and explosion of double base propellants as a function of aging time and found that decomposition shows a gradual increase and explosion a systematic decrease.
Abstract: Heats of decomposition and explosion of double base propellants were measured as a function of aging time. They show opposite trends with aging time: heat of decomposition shows a gradual increase and heat of explosion a systematic decrease. This happens because nitroglycerin oozes out of the system during aging. The loosening of the bond between the liner and the propellant during aging was shown to be due to the contraction of the propellant which occurs on account of nitroglycerin migration from the propellant system.

1 citations

Journal ArticleDOI
TL;DR: In this paper, 3D RANS simulations are performed to study the multi jet interactions of a twin engine gimbal configuration of an aerospace vehicle at different time instants, and the results show that the distinct features of the jets are retained at the farthest downstream locations; although the pressure field reached the uniformity.
Abstract: 3D RANS simulations are performed to study the multi jet interactions of a twin engine gimbal configuration of an aerospace vehicle at different time instants. Simulations captured all the essential features of the flow field and interaction between the neighboring jets did not occur because of low altitudes and moderate under-expansion of the jets considered in the simulations. For higher gimbal angle, two jets were the closest but still did not interact. Detail exploration of the downstream flow field revealed that the distinct features of the jets are retained at the farthest downstream locations; although the pressure field reached the uniformity. Average base pressure ratios for the three different time instances are 0.91, 0.547 and 0.522 and maximum base temperature is of the order 800 K.

1 citations


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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20224
202117
202017
201923
201840
201735