
Mallick, Rajnish
This research investigates onblade partial span active plain trailing edge flaps (TEFs)with an aim to alleviate the helicopter vibrations. Among all the available smart materials, piezoelectric stack actuator(PEA)has shown its strong candidature for full scale rotor systems. Although, PEAs are quite robust in operation, however, they exhibit rate dependent hysteresis phenomenon and can generate only very small displacements. Dynamic hysteresis is a complex phenomenon which, if not modeled, can lead to drift in the vibration predictions. In this research, a comprehensive experimental analysis is performed on a commercially available piezostack actuator, APA500L, which is well suited for full scale applications....

Sarasija, S
Swirling flows abound in nature and numerous engineering applications. Under conditions which are not completely understood, the swirling cores could undergo a sudden enlargement of their vortex core, leading to a ’vortex breakdown’. The physics of vortex breakdown and strategies to control it have been active areas of research for nearly half a century. There are many competing theories of vortex breakdown in the literature; broadly, these are surmised on similarities to flow separation, hydrodynamic instability or transition from a supercritical to a subcritical state. However, a rational criterion for vortex breakdown continues to be elusive. One of the most...

Sunitha, M
Microfluidics deals with the behavior, control and manipulation of fluids which are confined at micrometer length scale. It has important application in labona chip technology, micropropulsion, additive manufacturing, and microthermal technologies. Microfluidics has been widely used in detection, separation, transportation, and mixing of fluids and particles.
The work carried out for the thesis to study the fluidstructure interaction in microchannel involves an experimental part and a simulation part. In the experimental part the characterization of biofluid (RBC in BSA) is carried out based on the power law of fluid and flow behavior is studied. Also the dependence of fluid concentration on...

Sunitha, M
Microfluidics deals with the behavior, control and manipulation of fluids which are confined at micrometer length scale. It has important application in labona chip technology, micropropulsion, additive manufacturing, and microthermal technologies. Microfluidics has been widely used in detection, separation, transportation, and mixing of fluids and particles.
The work carried out for the thesis to study the fluidstructure interaction in microchannel involves an experimental part and a simulation part. In the experimental part the characterization of biofluid (RBC in BSA) is carried out based on the power law of fluid and flow behavior is studied. Also the dependence of fluid concentration on...

Khatta, Abhishek
Shockshock interactions are among the most basic gasdynamic problem, and are almost unavoidable in any high speed light, where shock waves generating from different sources crosses each other paths. These interactions when present very close to the solid surface lead to very high pressure and thermal loads on the surface. The related practical problem is that experienced at the cowl lip of a scramjet engine, where the interfering shock waves leads to high heat transfer rates which may also lead to the damage of the material. The classification by Edney (1968) on the shockshock interaction patterns based on the visualization...

Khatta, Abhishek
Shockshock interactions are among the most basic gasdynamic problem, and are almost unavoidable in any high speed light, where shock waves generating from different sources crosses each other paths. These interactions when present very close to the solid surface lead to very high pressure and thermal loads on the surface. The related practical problem is that experienced at the cowl lip of a scramjet engine, where the interfering shock waves leads to high heat transfer rates which may also lead to the damage of the material. The classification by Edney (1968) on the shockshock interaction patterns based on the visualization...

Abdul Saleem, P K
Autonomous aerial vehicles like missiles and unmanned aerial vehicles (UAVs) have attracted various military and civilian applications. The primary guidance objective of any autonomous vehicle is to reach the desired destination point (target or waypoint). However, many practical engagements impose additional constraints like minimum control effort, a desired final velocity direction or a predefined engagement time. This thesis addresses engagement time constrained guidance problems pertaining to missiles and UAVs.
The first part of the thesis discusses a nonlinear guidance law for impact time control of missiles against stationary target. The guidance law is designed with a particular choice of missile...

Murthy, MVVS
Wave propagation is a phenomenon resulting from high transient loadings where the duration of the load is in µ seconds range. In aerospace and space craft industries it is important to gain knowledge about the high frequency characteristics as it aids in structural health monitoring, wave transmission/attenuation for vibration and noise level reduction.
The wave propagation problem can be approached by the conventional Finite Element Method(FEM); but at higher frequencies, the wavelengths being small, the size of the finite element is reduced to capture the response behavior accurately and thus increasing the number of equations to be solved, leading to high...

Keshava Kumar, S
Composite laminated structures are prone to delamination. Rotorcraft flexbeams, apart from many other aerospace primary load carrying members are made up of composite laminated structures. A delaminated primary load carrying member can lead to catastrophic failure of the system of which it is a part. Delamination modeling and detection in composite laminated structures are challenging areas of ongoing research worldwide.
Existing literature falls short of addressing effects of widthwise partial delamination on the modal characteristics of beams. To address this issue, a new partial delamination model for composite beams is proposed and implemented using the finite element method. Homogenized crosssectional...

Malik, Bijoy Kumar
Normal shock problems in high enthalpy flows are of special interests to aerodynamicists and fluid dynamicists. When the shock Mach number become hypersonic and increasing further, the gas passing through the shock is compressed resulting in increase in temperature and pressure.
As the Mach number increases the internal degrees of freedom of the diatomic molecules are activated to an increasing extent when it crosses the shock resulting dissociation especially for high enthalpy flows. Hence dissociation of diatomic molecules must be taken into account in the determination of some of the aerodynamic parameters. This thermal and chemical process can
be divided into three...

Malik, Bijoy Kumar
Normal shock problems in high enthalpy flows are of special interests to aerodynamicists and fluid dynamicists. When the shock Mach number become hypersonic and increasing further, the gas passing through the shock is compressed resulting in increase in temperature and pressure.
As the Mach number increases the internal degrees of freedom of the diatomic molecules are activated to an increasing extent when it crosses the shock resulting dissociation especially for high enthalpy flows. Hence dissociation of diatomic molecules must be taken into account in the determination of some of the aerodynamic parameters. This thermal and chemical process can
be divided into three...

Mondal, Partha
The thesis presents a two pronged approach for predicting aerodynamics of air foils/wings in the vicinity of the ground. The ﬁrst approach is eﬀectively a model for ground eﬀect studies, employing an inexpensive Discrete Vortex Method for the 2D pre dictions and the well known Numerical lifting line theory for the 3D predictions. The second one pertains to the dynamic ground eﬀect analysis which employs the state of the art moving mesh methodology based time accurate CFD. In that sense, the thesis deals with two ends of spectrum in the ground eﬀect analysis; one, a model to be used in...

Mondal, Partha
The thesis presents a two pronged approach for predicting aerodynamics of air foils/wings in the vicinity of the ground. The ﬁrst approach is eﬀectively a model for ground eﬀect studies, employing an inexpensive Discrete Vortex Method for the 2D pre dictions and the well known Numerical lifting line theory for the 3D predictions. The second one pertains to the dynamic ground eﬀect analysis which employs the state of the art moving mesh methodology based time accurate CFD. In that sense, the thesis deals with two ends of spectrum in the ground eﬀect analysis; one, a model to be used in...

Varghese, Albin B M
Rapid mixing and spreading of supersonic jets are two important characteristics in supersonic ejectors, noise reduction in jets and fuel mixing in supersonic combustion. It helps in changing the acoustic and thermal signature in supersonic exhaust. The supersonic nozzles in most cases result in compressible mixing layers. The subsonic nozzles form incompressible mixing layers but at high Mach numbers even they form compressible mixing layers. Compressible mixing layers have been found to have much lower mixing and spreading rates than incompressible mixing layer Birch & Eggers (1972).
In order to enhance the spreading and mixing of mixing layers from supersonic...

Vankeswaram, Sai Krishna
Biofuels in civil aviation is actively studied in recent years to identify potential alternative jet fuels to meet stringent environmental regulations imposed to tackle degraded air quality caused by fossil fuel combustion. In this context, the aviation industry prefers to develop ‘dropin’ fuels which may not require substantial modifications in existing jet engine technologies. The thesis aims at evaluating the atomization characteristics of camelina and jatrophaderived dropin biofuels discharging from simplex swirl atomizer used in aircraft gas turbine engines. The test fuels are characterized in detail and all fuels meet current ASTM D7566 specifications. The experiments are conducted by discharging...

Vankeswaram, Sai Krishna
Biofuels in civil aviation is actively studied in recent years to identify potential alternative jet fuels to meet stringent environmental regulations imposed to tackle degraded air quality caused by fossil fuel combustion. In this context, the aviation industry prefers to develop ‘dropin’ fuels which may not require substantial modifications in existing jet engine technologies. The thesis aims at evaluating the atomization characteristics of camelina and jatrophaderived dropin biofuels discharging from simplex swirl atomizer used in aircraft gas turbine engines. The test fuels are characterized in detail and all fuels meet current ASTM D7566 specifications. The experiments are conducted by discharging...

Sundaram, Iyer Arvind
This thesis is concerned with studies on spatially developing high speed mixing layers with twin objectives: (a) to provide enhanced and detailed understanding of spatial development of twodimensional mixing layer emanating from splitter plate through large eddy simulation (LES, from now on) technique and (b) to evolve a consistent strategy for Unsteady Reynolds Averaged NavierStokes (URANS) approach to mixing layer calculations.
The inspiration for this work arose out of the explanations that were being developed for the reduction in the mixing layer thickness with compressibility (measured by a parameter called convective Mach number, Mc). The reasons centered around increased stability,...

Sudhakar, V
Sandwich constructions are the most commonly used structures in aircraft and navy industries, traditionally. These structures are made up of the face sheets and the core, where the face sheets will be taking the load and is connected to other structural members, while the soft core material, will be used to absorb energy during impact like situation. Thus, sandwich constructions are mainly employed in light weight structures where the high energy absorption capability is required. Generally the face sheets will be thin, made up of either metallic or composite material with high stiffness and strength, while the core is light...

Mysa, Ravi Chaithanya
This study seeks to understand the interplay of vorticity and elastodynamics that forms the basis for a fluttering flag and flapping wing propulsion, and factors that distinguish one from the other. The fluid dynamics is assumed two dimensional and incompressible, and comprises potential and viscous flow simulations. The elastic solid is one dimensional and governed by the BernoulliEuler flexure model. The fluid and elastic solid models are coupled using a predictorcorrector algorithm. Flutter of a flag or foil is associated with drag and we show that the pressure on the foil is predominantly circulatory in origin. The circulatory pressure generated...

Mysa, Ravi Chaithanya
This study seeks to understand the interplay of vorticity and elastodynamics that forms the basis for a fluttering flag and flapping wing propulsion, and factors that distinguish one from the other. The fluid dynamics is assumed two dimensional and incompressible, and comprises potential and viscous flow simulations. The elastic solid is one dimensional and governed by the BernoulliEuler flexure model. The fluid and elastic solid models are coupled using a predictorcorrector algorithm. Flutter of a flag or foil is associated with drag and we show that the pressure on the foil is predominantly circulatory in origin. The circulatory pressure generated...