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.

Estimation of loss factors of a constrained layer plate using viscoelastic layer

Abstract: A finite element method is developed and validated for the estimation of loss factors of a viscoelastically damped plate. Viscoelastic layer is used as constrained layer and is sandwiched between a...

Numerical study of hot launch of missile inside a tube

Abstract: The impingement of hot rocket motor plume inside a canister is simulated numerically by solving three-dimensional Reynolds Averaged Navier–Stokes equations using commercial software. The computed methodology is first validated for cold flow jet impingement in a circular tube for different chamber pressure and the simulations captured all the finer aspects of blow-by flow conditions as reported in the literature. A very good comparison is obtained between experimental and numerical surface pressure distribution. The validated methodology is applied to simulate the hot launch of a missile from a canister. It is observed that for low annular gap between missile body and canister the motor plume interaction became intense and gave rise to a very significant base drag which may constrain the motion of the missile inside the canister.

Development of a Thermo-chemical Non-equilibrium Solver for Hypervelocity Flows

Abstract: In the present study, a three dimensional flowsolver is indigenously developed to numerically simulate hypervelocity thermal and chemical non equilibrium reactive air flow past flight vehicles. The two-temperature, five species, seventeen reactions, thermo-chemical non equilibrium, non-ionizing, air-chemistry model of Park is implemented in a compressible viscous code CERANS and solved in the finite volume framework. The energy relaxation is addressed by a conservation equation for the vibrational energy of the gas mixture resulting in the evaluation of its vibrational temperature. The AUSM-PW+ numerical flux function has been used for modeling the convective fluxes and a central differencing approximation is used for modeling the diffusive fluxes. The flowsolver had been validated for specifically chosen test cases with inherent flow complexities of non-ionizing hypervelocity thermochemical nonequilibrium flows and results obtained are in good agreement with results available in open literature.

Friction Buttering: A New Technique for Dissimilar Welding

Abstract: This work offers a fresh perspective on buttering, a technique often considered for fusion welding of dissimilar metals. For the first time, buttering was attempted in solid state using friction deposition. Using this new “friction buttering” technique, fusion welding of two different dissimilar metal pairs (austenitic stainless steel/borated stainless steel and Al-Cu-Mg/Al-Zn-Mg-Cu) was successfully demonstrated. The results show that friction buttering can simplify a tough dissimilar welding problem into a routine fusion welding task.