Mechanical & Manufacturing Engineering Taught Masters, Erasmus Mundus (Theses & Dissertations)
http://hdl.handle.net/2262/9898
2017-03-29T17:01:30ZStudy of Parallel implementation of Computational codes
http://hdl.handle.net/2262/23960
Study of Parallel implementation of Computational codes
Tyagi, Shekhar
The use of computers to solve scientific problems is abundant and almost a need of the day. As the complexity of the problems increased, the need to get fast and accurate results has also taken an altogether different meaning. The area where one needs to use all the resources at disposal to compute the results efficiently and quickly is known as HPC (High Performance Computing). Evolution of computers has given the idea of using the entire RAM at disposal while computing the results; hence, parallelization becomes highly desirable.
The goal of this project is to parallelize distributed memory systems using WINDOWS platform, analyzing some small(computationally) parallelized problems and if possible then trying to implement them for the software ABAQUS(FEM tool). Moreover the parallel program developed can be used for numerical solution to Helmholtz equation.
The basic equation governing acoustics is the Helmholtz equation; analytical complications have driven researchers to develop Numerical methods to solve this equation. Numerical methods in turn have posed computational difficulties even with the use of modern day computers, parallelization of solution of Helmholtz equation is the result of these problems. The standard algorithms are available for the Numerical methods and they only need to be programmed on a platform which can support parallel programming. By the implementation of suitable parallel techniques a considerable amount of efficiency with respect to time in obtaining the solutions can be achieved.
2008-11-05T10:31:22ZThe Use of CFD for Investigating Fluidelastic Instability in Tube Arrays
http://hdl.handle.net/2262/11022
The Use of CFD for Investigating Fluidelastic Instability in Tube Arrays
Sanches, Rafael Adriano Kuche
There are several applications of tube arrays subject to cross flow in the industry, mostly for heat exchanging. These tubes are subject to forces arising due to the flow, and under certain conditions they can experience large amplitude self exited vibration, phenomenon named Fluidelastic Instability (FEI), a potentially catastrophic phenomenon when occurring in structures dimensioned for static loads. Through this work a brief review of the different methods of modelling FEI is presented, and the use of the commercial Computational Fluid Dynamics (CFD) solver FLUENT to predict the forces acting in a tube of an array subject to cross flow is analyzed. A few experiments are performed in order to compare the simulation results to real data. Finally, the Reynolds Stress Model (RSM) is found to provide better results, but still not very faithful to the reality. Guidelines for preparation of a good simulation of flow through a tube array, mesh construction and turbulent models are presented. A comparison between results from several turbulent models is presented. The most appropriate model is then chosen and more results are presented. Future work is pointed to simulation with dynamic mesh and to a methodology of adaptation of CFD results for quasi steady fluidelastic instability model.
2007-01-01T00:00:00ZAcoustic particle velocity measurement by ultra-light membrane and its applications in acoustic holography
http://hdl.handle.net/2262/11021
Acoustic particle velocity measurement by ultra-light membrane and its applications in acoustic holography
ZHOU, ZE
Acoustic holography is a non-destructive method used to determine the spatial propagation of acoustical waves. Conventionally, the acoustic holography measures the acoustic pressure. Until recently, a very limited number of techniques to measure the acoustic particle velocity have been introduced.
The Laboratory of Vibration and Acoustics of INSA de Lyon, France has recently developed a novel method to directly measure the acoustic velocity field by a light membrane, with the assistance of a laser vibrometer.
Theories allowing getting acoustic pressure and acoustic power from particle velocity have also been developed.
The primary goal of this project is to apply the recently developed theories to a series of acoustic measurements. The objectives consist of the validation of the method and the evaluation of its performances under various circumstances.
In several experiments, results obtained by the approach of membrane?s measurement are compared with results from conventional microphone?s measurement and a relatively new P-U probe measurement.
2007-01-01T00:00:00ZAnalysis of the rough contact in axisymmetric upsetting
http://hdl.handle.net/2262/11020
Analysis of the rough contact in axisymmetric upsetting
Cui, Yu
Characterization of surface roughness is important in the frictional behavior of two contact surfaces. In general, it has been found that friction increases with average roughness. The prediction of friction and stress/ strain/ deformation is of interest in the friction-sensitive process such as aximmetric upsetting. However, the classical friction laws, such as Coulomb's law and its extension - Coulomb-Amonton's law, Coulomb-Orowan are found to be coarse and oversimplified especially in the presence of surface complexities.
The first objective of this project is to examine the microscopic evolution of the upsetting process with Finite Element software, with the focus on the interaction between the tool asperity and the plastic wave. The second objective is to evaluate Coulomb?s law and Plastic wave theory based on small-scale numerical models. The third objective is to implant the friction laws and prior findings into the experiment-size Finite Element models so that comparison between simulation and expriments could be made.
This project is a contribution to the definition of a new friction test for bulk forming processes.
2007-01-01T00:00:00Z