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    Numerical Simulation of Incompressible Flows over two Dimensional Geometries by Means of Immersed Boundary Method

    , M.Sc. Thesis Sharif University of Technology Shahmardi, Armin (Author) ; Hejranfar, Kazem (Supervisor)
    Abstract
    Two-dimensional incompressible flow analysis is one the most important applied issues in engineering and applied science field. Numerical solution of governing equations of flow requires exact computational grid generation.In complex geometries, generation of the grid which is coincident to the body is very difficult and time consuming. Immersed boundary method is an appropriate superseded method of body conformal grid generation in flow field numerical solution. In this method a grid which is not coincidentto bodyis generated and flow field properties are modified on points adjacent to the boundary of the object (Ghost Cell Method) to satisfy boundary conditions.
    The purpose of this... 

    Design and Manufacturing of a Multi Functional Device For Experimental Fatigue Test and Special Facilities for Symmetric and Anti Symmetric Loading on Gears

    , M.Sc. Thesis Sharif University of Technology Armin, Amir (Author) ; Durali, Mohammad (Supervisor)
    Abstract
    The goal of this research is design and manufacturing of a device for fatigue test and 3D crack propagation in spur gear roots. Clearly it should be able to test gear in oscillated bending load and control the amplitude and period of loading. Designed setup in this project using a electro hydraulic actuator can do it up to 50 KN and 10 Hz in amplitude and frequency and a PLC controls it during the test time. System can load gears symmetric or anti symmetric and simulate the effect of shaft misalignments, bearing damage and gear production tolerances on the gear loading. System completely designed, built and tested during this project and using experimental data, its performance was... 

    Optimization of Heat Recovery and Water Capture System from Boiler Flue Gas

    , M.Sc. Thesis Sharif University of Technology Armin, Bahman (Author) ; Saboohi, Yadollah (Supervisor)
    Abstract
    Thermal energy and water in flue gases varies with the type of fuel and thermal conversion system. Flue gas temperature is maintained in the range of 140 (℃) to 200 (℃) and it is subject to the sulfur content of the fuel. Vapor content of the flue gas is in the range of 10%_20% of volumetric flow. Considerable part of vapor may be recovered which can be used as cooling water make up. There are various means and methods for water capture and heat recovery which includes shell-tube heat exchanger among others. Selection of appropriate material and heat exchanger is conditioned by corrosion, temperature of flue gas and it’s economic feasibility. Identification of an optimal design of... 

    Wake interference of two identical oscillating cylinders in tandem: An experimental study

    , Article Ocean Engineering ; Volume 166 , 2018 , Pages 311-323 ; 00298018 (ISSN) Armin, M ; Khorasanchi, M ; Day, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    This study aims to assess the impact of the spacing between cylinders on their dynamic behaviour. Observations during this experiment have helped to identify the effect of spacing on excitation mechanism of each cylinder as well as establishing the relationship between cylinders response and the spacing between them. Arrays of cylindrical Structures in close proximity are common in variety of engineering structures, particularly in the offshore industry. If the cylinders are flexible, and are subject to excitation from fluid flow, then the dynamics is influenced by complex interactions between the cylinders, dependent on a variety of parameters. Two cylinders were flexibly mounted in tandem... 

    On the development of a nonlinear time-domain numerical method for describing vortex-induced vibration and wake interference of two cylinders using experimental results

    , Article Nonlinear Dynamics ; 2021 ; 0924090X (ISSN) Armin, M ; Day, S ; Karimirad, M ; Khorasanchi, M ; Sharif University of Technology
    Springer Science and Business Media B.V  2021
    Abstract
    A nonlinear mathematical model is developed in the time domain to simulate the behaviour of two identical flexibly mounted cylinders in tandem while undergoing vortex-induced vibration (VIV). Subsequently, the model is validated and modified against experimental results. Placing an array of bluff bodies in proximity frequently happens in different engineering fields. Chimney stacks, power transmission lines and oil production risers are few engineering structures that may be impacted by VIV. The coinciding of the vibration frequency with the structure natural frequency could have destructive consequences. The main objective of this study is to provide a symplectic and reliable model capable... 

    A Semi-Supervised Algorithms for Clustering Microarray Data

    , M.Sc. Thesis Sharif University of Technology Eslamzadeh, Habibollah (Author) ; Mahdavi Amiri, Nezamoddin (Supervisor) ; Madadkar Sobhani, Armin (Supervisor)
    Abstract
    Microarray which is also known as Biochip is a flat substrate of glass with the size of 1 ×1 cm on which a numerous number of biosensors are placed in an array format. Microarray DNAs are used to measure expression level of thousands of genes. Repeating these experiments in different conditions can result in patterns of expression. After preparation, the florescent sample is hybridized with the sensors of microarray surface and fluoresce intensities of the spots are measured by a special camera called CCD. The obtained pictures are examined by a computer and the spot lights converted into numerical data by image processing algorithms. Putting these numbers into matrices of size m×n is...