Recursos de colección

ETD at Indian Institute of Science (2.602 recursos)

Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.

Mechanical Engineering (mecheng)

Mostrando recursos 1 - 8 de 8

  1. Exploration And Assessment of HCCI Strategies for a Multi-Cylinder Heavy-Duty Diesel Engine

    Pandey, Sunil Kumar
    Homogeneous Charge Compression Ignition (HCCI) combustion is an alternative combustion mode in which the fuel is homogeneously mixed with air and is auto-ignited by compression. Due to charge homogeneity, this mode is characterized by low equivalence ratios and temperatures giving simultaneously low nitric oxide (NOx) and soot in diesel engines. The conventional problem of NOx-soot trade-off is avoided in this mode due to absence of diffusion combustion. This mode can be employed at part load conditions while maintaining conventional combustion at high load thus minimizing regulatory cycle emissions and reducing cost of after-treatment systems. The present study focuses on achieving...

  2. Novel Compression Fracture Specimens And Analysis of Photoelastic Isotropic Points

    Kamadi, V N Surendra
    Compression fracture specimens are ideally suited for miniaturization down to tens of microns. Fracture testing of thermal barrier coatings, ceramics and glasses are also best accomplished under compression or indentation. Compression fracture specimen of finite size with constant form factor was not available in the literature. The finite-sized specimen of edge cracked semicircular disk (ECSD) is designed which has the property of constant form factor. The novel ECSD specimen is explored further using weight function concept. This thesis, therefore, is mainly concerned with the design, development and geometric optimization of compression fracture specimen vis a vis their characterization of form...

  3. Geometric Reasoning with Mesh-based Shape Representation in Product Development

    Adhikary, Nepal
    Triangle meshes have become an increasingly popular shape representation. Given the ease of standardization it allows and the proliferation of devices (scanners, range images ) that capture and output shape information as meshes, this representation is now used in applications such as virtual reality, medical imaging, rapid prototyping, digital art and entertainment, simulation and analysis, product design and development. In product development manipulation of mesh models is required in applications such as visualization, analysis, simulation and rapid prototyping. The nature of manipulation of the mesh includes annotation, interactive viewing, slicing, re-meshing, mesh optimization, mesh segmentation, simplification and editing. Of these...

  4. A Numerical Study of Droplet Dynamics in Viscoelastic Flows

    Arun, Dalal Swapnil
    The polymers are integral part of vast number of products used in day to day life due to their anomalous viscoelastic behaviour. The remarkable flow behaviour exhibited by the polymeric fluids including rod climbing, extrudate swell, tube-less siphon, viscoelastic jet, elastic recoil and sharkskin instability is attributed to the complex microstructures in the polymeric liquids that arise due to the interactions of long chain polymer molecules with each other and with the surrounding fluid particles. The significance of polymer in transportation, packaging, pharmaceutical, chemical, biomedical, textiles, food and polymer processing industries highlights the requirement to comprehend the complex rheology of...

  5. Influence of Contact Stresses on Shape Recovery in Sputter Deposited NiTiCu Thin Films

    Gelli, N V R Vikram
    NiTiCu is a shape memory alloy that regains its original shape after large amount of shape changing deformation when heated above a critical temperature called reverse martensitic trans-formation temperature( Af). When external load is applied on the sample in twinned martensite phase at low temperature, it deforms by detwinning, accommodating large amount of strains. When it is heated above Af, the shape recovers by transformation of the martensite to austenite phase. However, the amount of shape recovery degrades over time due to internal factors such as precipitates, residual strains and thermal history as well as external factors such as stresses....

  6. Analytical Investigations on Linear And Nonlinear Wave Propagation in Structural-acoustic Waveguides

    Vijay Prakash, S
    This thesis has two parts: In the first part, we study the dispersion characteristics of structural-acoustic waveguides by obtaining closed-form solutions for the coupled wave numbers. Two representative systems are considered for the above study: an infinite two-dimensional rectangular waveguide and an infinite fluid- filled orthotropic circular cylindrical shell. In the second part, these asymptotic expressions are used to study the nonlinear wave propagation in the same two systems. The first part involves obtaining asymptotic expansions for the fluid-structure coupled wave numbers in both the systems. Certain expansions are already available in the literature. Hence, the gaps in the literature...

  7. Interaction of Bubbles with Vortical Structures

    Jha, Narsing Kumar
    Bubbly turbulent flows occur in a variety of industrial, naval and geophysical problems. In these flows, the bubbles in the flow interact with turbulence and/or vortical structures present in the continuous phase, resulting in bubble motion and deformation, and at the same time modifying the turbulence and/or vortical structures. Despite the fact that this has been a subject of interest for some time, mechanisms of bubble break-up due to turbulence and turbulence modulation due to bubbles are not well understood. To help understand this two-way coupled problem, we study in this thesis, the interaction of single and multiple bubbles with...

  8. Development And Investigation of Two-Stage Silica Gel + Water Adsorption Cooling Cum Desalination System

    Mitra, Sourav
    The present research work caters to two important needs of rural India: i) desalination of subsoil/coastal brackish water and ii) basic refrigeration for short term preservations of agro-produce, medicines etc. Fortunately, such places are blessed with abundant solar insolation and/or low grade thermal energy (< 100°C) is available which may be tapped for this purpose instead of relying solely on grid electricity. Both the objectives of desalination and cooling are realized by evaporating brackish water at a low pressure (~1 kPa) and thermally compressing the water vapour to a higher pressure before condensing it. Adsorption route is chosen for compression...

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