Search for: three-dimensional-model
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    CFD-DEM simulation of the hole cleaning process in a deviated well drilling: the effects of particle shape

    , Article Particuology ; Volume 25 , 2016 , Pages 72-82 ; 16742001 (ISSN) Akhshik, S ; Behzad, M ; Rajabi, M ; Sharif University of Technology
    We investigate the effect of particle shape on the transportation mechanism in well-drilling using a three-dimensional model that couples computational fluid dynamics (CFD) with the discrete element method (DEM). This numerical method allows us to incorporate the fluid-particle interactions (drag force, contact force, Saffman lift force, Magnus lift force, buoyancy force) using momentum exchange and the non-Newtonian behavior of the fluid. The interactions of particle-particle, particle-wall, and particle-drill pipe are taken into account with the Hertz-Mindlin model. We compare the transport of spheres with non-spherical particles (non-smooth sphere, disc, and cubic) constructed via the... 

    Flow-Field Modeling and Performance Prediction of Axial-Flow Compressors using Streamline Curvature Method

    , M.Sc. Thesis Sharif University of Technology Kohandel, Hamed (Author) ; Ghofrani, Mohammad Bagher (Supervisor) ; Nouri Borujerdi, Ali (Supervisor)
    Compressors are one of the most important components of gas turbines and turbomachinery processes. Thus some precise and quick tools are needed for design and analysis purposes. Despite of vast development of Computational Fluid Dynamics (CFD) tools, Through-Flow Streamline Curvature Methods (SCM) has retained their position. 2D and quasi-3D forms of SCM in combination with CFD results nowadays make more than 80% of turbomachinery design process of axial and radial compressors and turbines. In this thesis, the basics of developing a tool for axial-flow compressor analysis are introduced. As will be seen, this analysis tool can be used for design purposes too. The method that is chosen for... 

    Evaluation of the Performance of Fluid Dampers in Controlling the Seismic-Induced Response of Structures

    , M.Sc. Thesis Sharif University of Technology Jahromi Shirazi, Mohammad Mahdi (Author) ; Rahimzadeh Rofooei, Fayaz (Supervisor)
    Natural disasters, such as earthquakes and hurricanes, can strike without warning, resulting in a range of destruction from structural damage to loss of life. For this reason, research on structural control, which provides a new basis for design of structural systems against winds, earthquakes, waves, and traffic loadings, become of interest in civil engineering. This thesis focuses on using fluid dampers as a passive energy dissipation device. Viscous Fluid Dampers (VFD) are the most commonly used passive energy dissipation devices that are manufactured in various forms. However, the orifice type of Viscous Fluid Damper (VFD) is considered for structural applications. In this thesis, the... 

    Study of the Effect of Central Beam Column (CBC) Structure on Sequential Excavation of Large Span Underground Station

    , M.Sc. Thesis Sharif University of Technology Valizade Givi, Amir (Author) ; Ahmadi, Mohammad Mehdi (Supervisor)
    Effect of utilizing Central Beam Column (CBC) structure on shallow, large span underground spaces excavation is studied. The CBC method focuses on increasing the overall rigidity of tunnel supporting system prior to full face excavation, in which central drift excavation is limited to the dimensions of the central beam and column to reduce disturbances. Constructing the central beam and column structure, the excavation is completed with NATM excavation method in a symmetric manner about centerline. In CBC method on each side of the centerline there is an arch structure composed of the initial lining resting on roof beam on top and bottom beam at the invert. The roof and bottom beams take the... 

    Verification of Two and Three Dimensional Seepage Analyses Results’ Correctness in Embankment Dams According to Instrumenting Data (Case Study: ZAGROS, SHIAN & HAALEH Dams)

    , M.Sc. Thesis Sharif University of Technology Yarahmadi, Nazanin (Author) ; Jafarzadeh, Fardin (Supervisor)
    Since, seepage- related problems account for more than forty percents of earth dams’ failure, seepage analysis is one of the most important stages in designing of embankment dams. The most usual method of making a seepage analysis is doing a two dimensional one in the maximum cross- section and generalizing its results to the third dimension. As a natural consequence of this kind of seepage analysis, the effect of valley shape and material properties’ changes along the third dimension are ignored and so, in narrow valleys where the cross-section changes along longitude profile or in the specific cases of nonhomogeneity, using this kind of analysis can make false results. Besides, because of... 

    3D Modeling of Soccer Players from an Arbitrary Viewpoint Using Multi-view video images

    , M.Sc. Thesis Sharif University of Technology JebalBarezi Sarbijan, Elham (Author) ; Kasaei, Shohreh (Supervisor)
    For penalty detection and interpretation of sport match scenes (such as soccer), it is sometimes necessary to watch the scene from an arbitrary viewpoint captured by a virtual camera. In this research, we focus on 3D reconstruction of soccer players using videos that are captured from relatively far distance to the soccer field. In capturing videos from sport scenes, such as soccer scenes, an important issue is the problem of capturing videos from a wide environment to cover almost all parts of the field. Using many cameras with overlapped views might be an answer to this problem but it is impractical due to its cost for capturing and transmitting the data. Furthrmore, because of capturing... 

    3D Reconstruction of Football Player Using Multi-view Videos

    , M.Sc. Thesis Sharif University of Technology Karami, Mansoureh (Author) ; Kasaei, Shohreh (Supervisor)
    One major problem in sport match analysis and interpretation is that there are restricted viewpoints of the game. 3D reconstruction allows us to have virtual replay from any viewpoint so that the events such as penalties can be detected easily. For achieving this purpose, we use many cameras with overlapped views that cover almost all parts of the field. After some preprocessing, 3D reconstruction and texture mapping, we can enhance the viewer experience by having arbitrary viewpoint of the match. In this research, we use two different visual hull methods for 3D reconstruction. In the first method, the visual hull of an object is computed efficiently and robustly from image contours. This... 

    Control of Experimental Swarm Robots for Identification, Imaging & 3D Modeling Purposes

    , M.Sc. Thesis Sharif University of Technology Moeini, Mohammad (Author) ; Alasty, Aria (Supervisor)
    The aim of this project is decentralized control of a group of robots (swarm robots); such that the aggregation maneuver, leader following, Identification and imaging the target, will be performed so good as to make a three-dimensional model of the target from these images. Swarm robots consist of a number of similar and limited features robots which interaction in a group of robots, will lead to special features for the group. Any agent of group decides what to do only with its local information from the environment. Swarm robots are more applicable for the jobs in which a distributed perception from the environments needed, for example space exploration and military operations.In this... 

    Solidification of Fluid Inside the Pipeline to Fix or Replace the Defective Component

    , M.Sc. Thesis Sharif University of Technology Taheri, Mohammad Ali (Author) ; Saeedi, Mohammad Hassan (Supervisor)
    Pipe freezing has become well established in industry as a method of short-termisolation in order to carry out maintenance or repairs. It is often necessary to repair system components without plant shutdown or drainage of system having many piping structures which may have hazardous or expensive fluid. Therefore, a series of tests has been arranged to investigate the ice plug formation in two standard pipes with different diameter size. The freeze zone on the pipe has been created by means of an aluminum jacket which liquid nitrogen flows in it. In the tests the freezing time, amount of liquid nitrogen usage andthe pressure tolerance of ice plug have been determined. Moreover, the numerical... 

    3D Modeling South Three-Way Station1 of Mehrabad Airport and Tunnels Connected to the Station and Connecting Tunnel with Line4 of Metro Tehran

    , M.Sc. Thesis Sharif University of Technology Khoshdooni Farahani, Mohammad (Author) ; Sadaghiani, Mohammad Hossein (Supervisor)
    Recently, due to the major need of the development of underground spaces in dense urban areas, excavating tunnels near to the earth surface is arising. Therefore, there is a possibility that the new tunnels drill and construct in the vicinity or along the available tunnels. Thus, the interaction mechanism of this tunnels on each other and on land subsidence should be taken into consideration. In this research using ABAQUS finite element analysis software the interactions of the cross road subway station of Bimeh-Mehrabad airport in the line 4 of the Tehran city subway lines which is excavated using multistage drilling method is investigated. This model includes Eastern, Western and a... 

    Experimental and Theoretical Investigation on Losses and Modeling Axial Flow Turbine

    , M.Sc. Thesis Sharif University of Technology Hashemi, Ahmad (Author) ; Hajilouy-Benisi, Ali (Supervisor)
    Prediction of axial flow turbine’s performance with different operating conditions due to the high costs and lack of reliable empirical data is always under developing. In this type of turbine, fluid flow is three-dimensional, viscous and highly turbulent. Nowadays, although a relatively detailed picture of the flow field can be obtained by the computational and numerical tools, but using of appropriate loss models in one-dimensional modeling for the performance prediction as well as optimization of the turbine in initial design phases, is a common trend.
    In the current study, aerodynamic losses in the axial flow turbine are investigated. Several loss models for the axial flow turbines... 

    Analysis of a more realistic well representation during secondary recovery in 3-D continuum models

    , Article Computational Geosciences ; Volume 21, Issue 5-6 , 2017 , Pages 1035-1048 ; 14200597 (ISSN) Sadeghnejad, S ; Masihi, M ; Sharif University of Technology
    The effectiveness of secondary recovery methods in reservoir development studies depends on the knowledge about how fluid-carrying regions (i.e. good-quality rock types) are connected between injection and production wells. To estimate reservoir performance uncertainty, comprehensive simulations on many reservoir model realisations are necessary, which is very CPU consuming and time demanding. Alternatively, we can use much simpler and physically based methods such as percolation approach. Classic percolation assumes connectivity between opposite 2-D faces of a 3-D system; whereas, hydrocarbon production is achieved through active wells that are one-dimensional lines (e.g. vertical,... 

    Investigating the effect of hybrid silica nanoparticles-copolymer on increasing oil recovery in a three dimensional porous media

    , Article Scientia Iranica ; Volume 24, Issue 6 , 2017 , Pages 3466-3475 ; 10263098 (ISSN) Golshokooh, S ; Ramazani, A. S. A ; Hekmatzadeh, M ; Sharif University of Technology
    In this work, hybrid of silica nanoparticles (NPs) with sulfonated copolymer has been prepared in order to improve the copolymer properties for Enhanced Oil Recovery (EOR). Some tests are done to find the effectiveness of injecting fluid on Recovery Factor (RF), such as Contact Angle (CA), interfacial tension (IFT), inherent viscosity, and eventually Micro-Model (MM) flooding. In CA test, wettability alteration from Oil-Wet (OW) to Water-Wet (WW) is reached by sedimentation and adsorption of NPs on the rock slice. In addition, IFT reduction is obtained by increasing the NaCl concentration. The viscosity change is investigated for the hybrid and copolymer under simulated high-temperature oil... 

    Numerical assessment of new compound restrainer for seismic retrofit of bridges

    , Article Structure and Infrastructure Engineering ; 2017 , Pages 1-20 ; 15732479 (ISSN) Joghataie, A ; Pahlavan Yali, A ; Sharif University of Technology
    This paper studies through numerical simulation a practical compound restrainer to use for the improvement of seismic performance of bridges. A mechanical model has been introduced for the restrainer and a basic optimisation approach has been conducted to evaluate the performance of the restrainer to changes in the properties of its components. A real 2-span simply supported plate girder bridge has been selected for case study. Using a detailed three-dimensional model, several non-linear time history analyses were performed under seismic excitations in order to assess the performance of the bridge retrofitted by conventional restrainers including linear and non-linear viscous dampers on one... 

    Analysis of Stability and Ground Settlement in Construction Stages of Underground Exchange Station between Line 3 and 4 At Mashhad Subway

    , M.Sc. Thesis Sharif University of Technology Lamei, Amin (Author) ; Sadaghiani, Mohammad Hossein (Supervisor)
    Deformation and Settlement of the ground surface and stability of large underground space is the main concern in the excavation under urban area. In order to control settlement and increase stability, it is necessary to use pre-Supporting system prior to excavation. Concrete Arc Pre-supporting System (CAPS) is one of the most useful pre-supporting methods which is used in exchange station of line 3 and 4 of Mashhad subway. Line 3 and 4 are parallel in Shohada square and the groundwater level is above the whole station structure. To analyze deformation of the ground due to excavation stages, the station was modeled in 2D and 3D by Abaqus. In this study, to estimate ground Deformation, we need... 

    Biomechanical analysis of actin cytoskeleton function based on a spring network cell model

    , Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 231, Issue 7 , 2017 , Pages 1308-1323 ; 09544062 (ISSN) Ghaffari, H ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
    SAGE Publications Ltd  2017
    In this study, a new method for the simulation of the time-dependent behavior of actin cytoskeleton during cell shape change is proposed. For this purpose, a three-dimensional model of endothelial cell consisting of cell membrane, nucleus membrane, and main components of cytoskeleton, namely actin filaments, microtubules, and intermediate filaments is utilized. Actin binding proteins, which play a key role in regulating actin cytoskeleton behavior, are also simulated by using a novel technique. The actin cytoskeleton in this model is more dynamic and adoptable during cell deformation in comparison to previous models. The proposed model is subjected to compressive force between parallel micro... 

    Urine concentrating mechanism modelling in rat kidney inner medulla

    , Article 2016 23rd Iranian Conference on Biomedical Engineering and 2016 1st International Iranian Conference on Biomedical Engineering, ICBME 2016, 23 November 2016 through 25 November 2016 ; 2017 , Pages 111-116 ; 9781509034529 (ISBN) Sanatkhani, S ; Saidi, M. S ; Banazadeh, M. H ; Sharif University of Technology
    Physicians use charts that are prepared by experiments on animals or humans to prescribe drug dosage for patients. This method requires some precious amount of time by the Ministry of Health to approve new drugs to be used in healthcare centers. Three-dimensional modeling of the inner medulla by considering the known physiological features help us to predict the distribution of a drug or any minerals in the kidney. In this study we present modeling of the important species distribution including Na+ and urea in the rat inner medulla that influence the urine concentrating mechanism. We use a C++ code to develop the inner medulla geometry based on physiological data to better capture the... 

    A three-dimensional constitutive model for magnetic shape memory alloys under magneto-mechanical loadings

    , Article Smart Materials and Structures ; Volume 26, Issue 1 , 2017 ; 09641726 (ISSN) Mousavi, M. R ; Arghavani, J ; Sharif University of Technology
    Institute of Physics Publishing  2017
    This paper presents a three-dimensional phenomenological constitutive model for magnetic shape memory alloys (MSMAs), developed within the framework of irreversible continuum thermodynamics. To this end, a proper set of internal variables is introduced to reflect the microstructural consequences on the material macroscopic behavior. Moreover, a stress-dependent thermodynamic force threshold for variant reorientation is introduced which improves the model accuracy. Preassumed kinetic equations for magnetic domain volume fractions, decoupled equations for magnetization unit vectors and appropriate presentation of the limit function for martensite variant reorientation lead to a simple... 

    Numerical study of hydrogen-air combustion characteristics in a novel micro-thermophotovoltaic power generator

    , Article Applied Energy ; Volume 199 , 2017 , Pages 382-399 ; 03062619 (ISSN) Alipoor, A ; Saidi, M. H ; Sharif University of Technology
    Elsevier Ltd  2017
    In the present work, a micro combustor for thermophotovoltaic (TPV) devices is proposed which is included a U-shaped microtube in a box with a secondary fluid in space between U-shaped microtube and box walls. By utilizing the three-dimensional CFD model, combustion characteristics of the premixed lean hydrogen-air mixture in the present micro combustor are studied numerically with detailed chemistry and transport taking into account heat transfer through the wall. The results show that the establishment of secondary flows and better preheating in the curved tubes is caused the flammability limits to be at least four times in comparison with straight tubes. Combustion characteristics are... 

    Three dimensional pressure transient behavior study in stress sensitive reservoirs

    , Article Journal of Petroleum Science and Engineering ; Volume 152 , 2017 , Pages 204-211 ; 09204105 (ISSN) Moradi, M ; Shamloo, A ; Asadbegi, M ; Dezfuli, A. D ; Sharif University of Technology
    Elsevier B.V  2017
    Stress sensitivity is a phenomenon that affects reservoir rock properties, such as permeability and therefore changes the well pressure transient behavior. This paper aims to study these behaviors in stress sensitive reservoirs and evaluate the pressure loss in such reservoirs during the process of hydrocarbon production. A power model is used to correlate the changes in permeability with pore pressure. A novel semi-implicit three-dimensional finite element method has been employed to numerically solve the flow problem. The numerical results have been validated by analytical results obtained in a non-sensitive reservoir. Pressure drawdown test for different scenarios has been studied. The...