Faculty Publications
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Item Effect of Geometric Parameters on Steady-State Supersonic Film Cooling of the Basic Conical Rocket Nozzle(Springer Science and Business Media Deutschland GmbH, 2024) Rahul, V.M.; Gnanasekaran, N.The current study proposes simulation results of supersonic film cooling of rocket nozzle by varying the geometric parameters. The study reveals that as the width of the injector opening for coolant injection was altered, the temperature variation trend near the walls differed based on the extent to which the width was increased or decreased. The results captured are shown in upcoming sections of this work. The second parameter varied was the angle of injection, where the variation of the cooling temperature after the injection point and the turbulence variation as a function of axial length were mainly focused. The temperature, turbulence, pressure, and density variation are also shown by varying the above parameters as a function of the axial length of the nozzle. The fluid used for primary and secondary flows was the air with different inlet and outlet pressures and temperatures as boundary conditions. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Heat transfer at the metal/chill interface during solidification of commercially pure aluminium square bar castings with cast iron chill at one end was investigated. Experiments were carried out for different chill thicknesses and superheats. The inner surface temperature of the chill initially was found to increase at a faster rate for higher superheats. The effect of chill thickness on the inner surface temperature of the chill was observed only after the heat from the solidifying casting had sufficient time to diffuse to the interior of the chill material. Inverse analysis of the non-linear one-dimensional Fourier heat conduction equation indicated the occurrence of peak heat flux at the end of filling of the mould. The effect of superheat on heat flux was minimal after filling. However, the effect of chill thickness had a significant effect on the heat flux after the occurrence of peak heat flux. Higher heat flux transients were estimated for castings poured at higher superheats. The corresponding heat transfer coefficients were also estimated and reported. The heat flux model presented in this work can be used for determination of casting/chill interfacial heat flux as a function of chill thickness and superheat. These heat flux transients could be used as boundary conditions during numerical simulation of solidification of the casting. © 2002 Elsevier Science B.V. All rights reserved.(Effect of chill thickness and superheat on casting/chill interfacial heat transfer during solidification of commercially pure aluminium) Gafur, M.A.; Haque, M.N.; Prabhu, K.2003Item For successful modelling of the solidification process, a reliable heat transfer boundary condition data is required. These boundary conditions are significantly influenced by the casting and mould parameters. In the present work, the effect of sodium modification melt treatment on casting/chill interfacial heat transfer during upward solidification of an Al-13% Si alloy against metallic chills is investigated using thermal analysis and inverse modelling techniques. In the presence of chills, modification melt treatment resulted in an increase in the cooling rate of the solidifying casting near the casting/chill interfacial region. The corresponding interfacial heat flux transients and electrical conductivities are also found to be higher. This is attributed to (i) improvement in the casting/chill interfacial thermal contact condition brought about by the decrease in the surface tension of the liquid metal on addition of sodium and (ii) increase in the electronic heat conduction in the initial solidified shell due to change in the morphology of silicon from a acicular type to a fine fibrous structure and increase in the ratio of the modification rating to the secondary dendrite arm spacing. © 2003 Elsevier B.V. All rights reserved.(Elsevier BV, Effect of modification melt treatment on casting/chill interfacial heat transfer and electrical conductivity of Al-13% Si alloy) Prabhu, K.; Ravishankar, B.N.2003Item Bending of sandwich plates with anti-symmetric angle-ply face sheets - Analytical evaluation of higher order refined computational models(2006) Swaminathan, K.; Patil, S.S.; Nataraja, M.S.; Mahabaleswara, K.S.The aim of the present study is to assess the accuracy of the few computational models based on various shear deformation theories in predicting the bending behaviour of sandwich plates with anti-symmetric angle-ply face sheets under static loading. Five two-dimensional models available in the literature are used for the present evaluation. The performance of the various models is evaluated on a simply supported laminated plate under sinusoidal loading. The equations of equilibrium are derived using the principle of minimum potential energy (PMPE). Analytical solution method using double Fourier series approach is used in conjunction with the admissible boundary conditions. The accuracy of each model is established by comparing the results of composite plates with the exact solutions already available in the literature. After establishing the correctness of the theoretical formulations and the solution method, benchmark results for transverse displacement, in-plane stresses, moment and shear stress resultants are presented for the multilayer sandwich plates. © 2006 Elsevier Ltd. All rights reserved.Item Effect of boundary conditions and convection on thermally induced motion of beams subjected to internal heating(2007) Malik, P.; Kadoli, R.; Ganesan, N.Numerical exercises are presented on the thermally induced motion of internally heated beams under various heat transfer and structural boundary conditions. The dynamic displacement and dynamic thermal moment of the beam are analyzed taking into consideration that the temperature gradient is independent as well as dependent on the beam displacement. The effect of length to thickness ratio of the beam on the thermally induced vibration is also investigated. The type of boundary conditions has its influence on the magnitude of dynamic displacement and dynamic thermal moment. A sustained thermally induced motion is observed with progress of time when the temperature gradient being evaluated is dependent on the forced convection generated due to beam motion. A finite element method (FEM) is used to solve the structural equation of motion as well as the heat transfer equation. © Springer-Verlag 2007.Item Combined optimisation simulation model for groundwater management policy options(2007) Yaragal, S.C.; Nagaraj, M.K.Water resources system being quite complex in-nature, modelling involves several variables and parameters. A large number of models have been developed for analysis of water resources system. Most of the models developed are of simulation optimisation type. In general water management models which generally use the governing partial differential equation of now, the problem is formulated using either finite difference techniques or finite element method. In this paper, a hybrid model is formulated which simulates the groundwater system and optimises the same. The model developed has been used to study the effects of variation in pumping factors on the optimal values and on the yearly yield from the system, for a chosen pattern of pumping. The model has been analysed for three different boundary conditions. The aquifer model is descritised into 64 grids and a particular pumping pattern is chosen in the present study. The governing partial differential equation for groundwater now is reduced to algebraic linear equations using finite differences scheme and they are then embedded as a set of constraints in the model. For the chosen pumping pattern, the pumping factor plays a key role, depending on the boundary conditions, in achieving an optimum solution. Here, minimisation of heads is considered for optimisation. The model helps in simulating a complex groundwater system and evaluating certain policy for groundwater management.Item Static analysis of functionally graded beams using higher order shear deformation theory(2008) Kadoli, R.; Akhtar, K.; Ganesan, N.Displacement field based on higher order shear deformation theory is implemented to study the static behavior of functionally graded metal-ceramic (FGM) beams under ambient temperature. FGM beams with variation of volume fraction of metal or ceramic based on power law exponent are considered. Using the principle of stationary potential energy, the finite element form of static equilibrium equation for FGM beam is presented. Two stiffness matrices are thus derived so that one among them will reflect the influence of rotation of the normal and the other shear rotation. Numerical results on the transverse deflection, axial and shear stresses in a moderately thick FGM beam under uniform distributed load for clamped-clamped and simply supported boundary conditions are discussed in depth. The effect of power law exponent for various combination of metal-ceramic FGM beam on the deflection and stresses are also commented. The studies reveal that, depending on whether the loading is on the ceramic rich face or metal rich face of the beam, the static deflection and the static stresses in the beam do not remain the same. © 2007 Elsevier Inc. All rights reserved.Item Uniformly-Convergent Numerical Methods for a System of Coupled Singularly Perturbed Convection-Diffusion Equations with Mixed Type Boundary Conditions(Taylor and Francis Ltd., 2013) Mythili Priyadharshini, R.M.; Ramanujam, N.In this paper, two hybrid difference schemes on the Shishkin mesh are constructed for solving a weakly coupled system of two singularly perturbed convection - diffusion second order ordinary differential equations subject to the mixed type boundary conditions. We prove that the method has almost second order convergence in the supremum norm independent of the diffusion parameter. Error bounds for the numerical solution and also the numerical derivative are established. Numerical results are provided to illustrate the theoretical results. © 2013 Vilnius Gediminas Technical University, 2013.Item Vibration analysis of a tapered laminated thick composite plate with ply drop-offs(Springer Verlag service@springer.de, 2015) Edwin Sudhagar, P.; Arumugam, A.; Vasudevan, R.; Jeyaraj, J.In this study, vibration characteristics of a tapered laminated thick composite plate have been investigated using finite element method by including the shear deformation and rotary inertia effects. The governing differential equations of motion of a tapered laminated thick composite plate are presented in the finite element formulation based on first-order shear deformation theory for three types of taper configurations. The effectiveness of the developed finite element formulation in identifying the various dynamic properties of a tapered laminated thick composite plate is demonstrated by comparing natural frequencies evaluated using the present FEM with those obtained from the experimental measurements and presented in the available literature. Various parametric studies are also performed to investigate the effect of taper configurations, aspect ratio, taper angle, angle ply orientation and boundary conditions on free and forced vibration responses of the structures. The comparison of the transverse free vibration mode shapes of the uniform and tapered composite plates under various boundary conditions is also presented. The forced vibration response of a composite plate is investigated to study the dynamic response of tapered composite plate under the harmonic force excitation in various tapered configurations. It is concluded that the dynamic properties of laminated thick composite plates could be tailored by dropping off the plies to yield various tapered composite plate. © 2015, Springer-Verlag Berlin Heidelberg.Item A finite element based assessment of static behavior of multiphase magneto-electro-elastic beams under different thermal loading(Techno-Press, 2017) Mahesh, M.; Kattimani, S.C.In this article, static analysis of a magneto-electro-elastic (MEE) beam subjected to various thermal loading and boundary conditions has been investigated. Influence of pyroeffects (pyroelectric and pyromagnetic) on the direct quantities (displacements and the potentials) of the MEE beam under different boundary conditions is studied. The finite element (FE) formulation of the MEE beam is developed using the total potential energy principle and the constitutive equations of the MEE material taking into account the coupling between elastic, electric, magnetic and thermal properties. Using the Maxwell electrostatic and electromagnetic relations, variation of stresses, displacements, electric and magnetic potentials along the length of the MEE beam are investigated. Effect of volume fractions, aspect ratio and boundary conditions on the direct quantities in thermal environment has been determined. The present investigation may be useful in design and analysis of magnetoelectroelastic smart structures and sensor applications. © 2017 Techno-Press, Ltd.