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    Three types of meshless finite volume method for the analysis of two-dimensional elasticity problems

    , Article Computational and Applied Mathematics ; Volume 36, Issue 2 , 2017 , Pages 971-990 ; 01018205 (ISSN) Ebrahimnejad, M ; Fallah, N ; Khoei, A. R ; Sharif University of Technology
    Springer Science and Business Media, LLC  2017
    Abstract
    This paper presents three schemes of 2D meshless finite volume (MFV) method, referred to as MFV with overlapping control volumes (MFV1), MFV with irregular non-overlapping control volumes (MFV2) and MFV with regular non-overlapping control volumes (MFV3). The methods utilize the local symmetric weak form of system equation and the interpolation functions constructed using the weighted multi-triangles method (WMTM) which is recently developed by the present authors. The proposed formulation involves only integrals over the boundaries of control volumes. The performance of the proposed schemes is studied in three benchmark problems. A comparative study between the predictions of the above MFV... 

    A multi-resolution multiscale finite volume method for simulation of fluid flows in heterogeneous porous media

    , Article Journal of Computational Physics ; Volume 248 , September , 2013 , Pages 339-362 ; 00219991 (ISSN) Mosharaf Dehkordi, M ; Taghizadeh Manzari, M ; Sharif University of Technology
    2013
    Abstract
    This paper presents an extension of the multiscale finite volume (MsFV) method to multi-resolution coarse grid solvers for single phase incompressible flows. To achieve this, a grid one level coarser than the coarse grids used in the MsFV method is constructed and the local problems are redefined to compute the basis and correction functions associated with this new grid. To construct the coarse-scale pressure equations, the coarse-scale transmissibility coefficients are calculated using a new multi-point flux approximation (MPFA) method. The estimated coarse-scale pressures are utilized to compute the multiscale pressure solution. Finally a reconstruction step is performed to produce a... 

    Numerical simulation of two-phase flow in airlift pumps using the Physical Influence Scheme

    , Article Progress in Computational Fluid Dynamics ; Volume 10, Issue 3 , 2010 , Pages 186-194 ; 14684349 (ISSN) Hanafizadeh, P ; Saidi, M. H ; Darbandi, M ; Kebriaee, A ; Sharif University of Technology
    2010
    Abstract
    A new approach has been presented to solve gas-liquid flow numerically in vertical pipes of air-lift pumps. To improve modelling, a new strategy has been employed with the capability of coupling the continuity and momentum equations and enforcing the role of pressure directly in the continuity equation. This is achieved via applying a novel scheme called the Physical Influence Scheme (PIS). The current finite volume solution is compared with other available numerical solutions. Indeed, they are in fair agreement. However, the present predictions are far superior to those obtained from an existing simple method, which is widely used in airlift pump modelling  

    Numerical modeling of nanofluid flow and heat transfer in a quartered gearwheel-shaped heat exchanger using FVM

    , Article Chinese Journal of Physics ; Volume 59 , 2019 , Pages 591-605 ; 05779073 (ISSN) Hooshmand, P ; Kavoosi Balootaki, H ; Mohammaei, M ; Bagheri, N ; Hasani Malekshah, E ; Sharif University of Technology
    Physical Society of the Republic of China  2019
    Abstract
    The numerical modeling of natural convection fluid flow and heat transfer in a quarter of gearwheel-shaped heat exchanger is carried out. The heat exchanger is included with internal active square bodies. These bodies have hot and cold temperatures with different thermal arrangements. Three different thermal arrangements are considered and showed with Case A, Case B and Case C. The CuO-water nanofluid is selected as operating fluid. The Koo-Kleinstreuer-Li (KKL) correlation is utilized to estimate the dynamic viscosity and thermal conductivity. In addition, the shapes of nanoparticles are taken account in the analysis. The Rayleigh number, nanoparticle concentration and thermal arrangements... 

    Effects of using altered coarse grids on the implementation and computational cost of the multiscale finite volume method

    , Article Advances in Water Resources ; Volume 59 , September , 2013 , Pages 221-237 ; 03091708 (ISSN) Mosharaf Dehkordi, M ; Manzari, M. T ; Sharif University of Technology
    2013
    Abstract
    In the present work, the multiscale finite volume (MsFV) method is implemented on a new coarse grids arrangement. Like grids used in the MsFV methods, the new grid arrangement consists of both coarse and dual coarse grids but here each coarse block in the MsFV method is a dual coarse block and vice versa. Due to using the altered coarse grids, implementation, computational cost, and the reconstruction step differ from the original version of MsFV method. Two reconstruction procedures are proposed and their performances are compared with each other. For a wide range of 2-D and 3-D problem sizes and coarsening ratios, the computational costs of the MsFV methods are investigated. Furthermore, a... 

    Modified multiscale finite volume method for two phase flow in porous media

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 7 A , 2013 ; 9780791856314 (ISBN) Saeidimanesh, M ; Eksiri, H ; ASME ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2013
    Abstract
    Multiscale finite volume (MSFV) method have been developed and applied in various complicated physics. The most important advantage of MSFV method is its computational efficiency. In this paper we present a new set of boundary condition for calculation of basis and correction functions which leads to further reduction in computational time in problems with medium heterogeneity and therefore improves computational efficiency. In standard MSFV (sMSFV) method reduced boundary condition is used to determine the basis and correction functions which is based on local information, however in modified MSFV (mMSFV) method global information is used at initial time for constructing boundary condition... 

    Surfactant effects on the efficiency of oil sweeping from the dead ends: Numerical simulation and experimental investigation

    , Article Chemical Engineering Research and Design ; Volume 94 , 2015 , Pages 173-181 ; 02638762 (ISSN) Kamyabi, A ; Ramazani, S. A. A ; Kamyabi, M ; Sharif University of Technology
    Institution of Chemical Engineers  2015
    Abstract
    Highlights: The objective of this work is to investigate the effects of the surfactants on the oil extraction from the dead ends through the numerical simulations and experimental evidences. The volume of fluid approach in the frame of the finite volume method has been used for numerical simulations in 2-D domain and experimental flooding tests have been done using a glassy micro-model. The effects of the water-oil, water-wall and oil-wall interfacial tensions have been investigated numerically and some results are compared to experimental flooding results. Simulations have been done in the cases of water-wet, neutralized-wet and oil-wet micro-models also. The numerical results show that in... 

    Multi-resolution Multiscale Finite Volume Method for Reservoir Simulation

    , Ph.D. Dissertation Sharif University of Technology Mosharaf Dehkordi, Mehdi (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)
    Abstract
    Many of natural porous media, especially oil reservoirs, have strong heterogeneities that span a wide range of scales. These heterogeneities are manifested in the form of strong variations in the permeability field. These variations can be of several orders of magnitude within a small distance. Therefore, the flow in porous media is a multiscale Phenomenon. Due to prohibitive size of input data, numerical simulation of such problems needs extremely large computer memory and computational time, which can be impractical in some cases. In recent years, multiscale methods as a powerful tool have been employed to tackle this problem. In present study, a family of non-iterative Multiscale Finite... 

    Rayan: A polyhedral grid co-located incompressible finite volume solver (Part I: Basic design features)

    , Article Scientia Iranica ; Volume 17, Issue 6 B , NOVEMBER-DECEMBE , 2010 , Pages 443-455 ; 10263098 (ISSN) Sani, M ; Saidi, M. S ; Sharif University of Technology
    2010
    Abstract
    In this work, basic design features of Rayan are documented. One of the new design features presented in this work is the way Rayan handles polyhedral grids. Grid definition is combined with the definition of the structure of the sparse coefficient matrix, thereby releasing a considerable part of the memory used by the grid to store otherwise required faces belonging to the cell part of the connectivity description. The key idea is to use a uniform way for creating the structure of the coefficient matrix from the grid connectivity description and to access that data when computing the elements of the coefficient matrix. This saving requires many modifications to the computational algorithm... 

    Conceptual linearization of euler governing equations to solve high speed compressible flow using a pressure-based method

    , Article Numerical Methods for Partial Differential Equations ; Volume 24, Issue 2 , 2008 , Pages 583-604 ; 0749159X (ISSN) Darbandi, M ; Roohi, E ; Mokarizadeh, V ; Sharif University of Technology
    2008
    Abstract
    The main objective of the current work is to introduce a new conceptual linearization strategy to improve the performance of a primitive shock-capturing pressure-based finite-volume method. To avoid a spurious oscillatory solution in the chosen collocated grids, both the primitive and extended methods utilize two convecting and convected momentum expressions at each cell face. The expressions are obtained via a physical-based discretization of two inclusive statements, which are constructed via a novel incorporation of the continuity and momentum governing equations. These two expressions in turn provide a strong coupling among the Euler conservative statements. Contrary to the primitive... 

    Developing a Software to Analyze Electroosmotic Flow in Microchannels

    , M.Sc. Thesis Sharif University of Technology Farzinpour, Pouyan (Author) ; Darbandi, Masoud (Supervisor)
    Abstract
    The fabrication of micron-sized instruments MEMS have been in fast progress in different fields of science and technology such as those of chemical processes in chemical engineering, propulsion in aerospace industries, microchip cooling and inkjet printers in electrical industries, and medical appliances in medical and biomedical science. They have forced the manufacturers and researchers to work and think in fabricating such small-scale sizes. However, the complexity of fabricating MEMS with moving parts has also promoted the manufacturers to think of alternative ways. For example the use of moving parts to pump fluid in such devises causes such difficulties and the researchers could adopt... 

    Numerical Simulation of Multi Stage Pulse Tube Refrigerators

    , M.Sc. Thesis Sharif University of Technology Ghahremani, Amir Reza (Author) ; Saeedi, Mohammad Hassan (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
    Abstract
    Multi stage Pulse Tube Cryocoolers (PTCs) have found the interest of researchers due to its reliability, long life and absence of moving part. This thesis represents a comprehensive numerical simulation method to investigate one and two stage PTC. All components of the PTC are modeled employing the nodal analysis technique to discretize the mass, momentum and energy conservation equations. SUTPTC code has been developed in cryocooler laboratory of Sharif University of Technology (SUT) to analyze and optimize one and two stage cryocooler performance. The SUTPTC code has been validated with the existing experimental data. Employing the proposed code, the effect of precooling temperature, the... 

    Solution of Compressible Flow Using Finite Volume Lattice Boltzmann Method on Unstructured Meshes

    , M.Sc. Thesis Sharif University of Technology Karbalaei baba, Ali Reza (Author) ; Hejranfar, Kazem (Supervisor)
    Abstract
    In this study, the solution of compressible flows is performed using finite volume lattice Boltzmann method (FVLBM). A model associated with 13 discrete velocity vectors and 2 energy levels is used and the Boltzmann transport equation is solved using a cell-centered finite volume on structured meshes. The values of distribution functions on each cell faceare determined by averaging from their values at the two control points located on the center of two neighboring cells. The fourth-order Runge-Kutta time-stepping scheme is applied to discretize temporal derivative term. The second- and fourth-order numerical dissipation termsareadded to the algorithm to stabilize the solution when solving... 

    Simulating the Effect of Cuff Pressure on Brachial Artery for Calculating the Photoplethysmography(PPG) Singnal

    , M.Sc. Thesis Sharif University of Technology Shiri, Farhad (Author) ; Firoozabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    One of the most important reasons of death in today’s world is the diseases related to cardiovascular system. Hypercholesterolemia is one of the most common forms of these diseases. There are a lot of experiments for diagnosing this disease, which are classified into two groups: invasive and noninvasive experiments. One of the well-known noninvasive experiments in this area is the photoplethysmography in which the changes of the photoplethysmography signal can reveal some valuable information about the cardiovascular system’s health.The objective of this study is to simulate the photoplethysmography experiment considering the clinical conditions of the experiment. In this work, the obtained... 

    A Finite Volume Method for Simulation of 2D Two-Phase Flow in Porous Medium with Anisotropic PermeabilityTensor on Unstructured Cell CenterTriangular Grid

    , M.Sc. Thesis Sharif University of Technology Moosavi, Abbas (Author) ; Taghi Zadeh Manzari, Mehrdad (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
    Abstract
    Rapid variation in permeability with strong anisotropy are common features in subsurface reservoirs. When formulating a finite-volume pressure equation scheme, continuous normal flux and pressure are key physical constraints that must be imposed at control-volume interfaces, across which strong discontinuities in permeability can occur.
    The derivation of algebraic flux continuity conditions for full-tensor discretization operators has lead to families of efficient locally conservative flux-continuous control-volume distributed (CVD) finite- volume schemes for determining the discrete pressure and elocity fields in subsurface reservoirs [5, 9, 11, 13].
    When applying these... 

    Central Difference Finite Volume Lattice Boltzmann Method for Simulation of Incompressible Electro-Magneto-Hydrodanamic Flows

    , M.Sc. Thesis Sharif University of Technology Taheri, Sina (Author) ; Hejranfar, Kazem (Supervisor)
    Abstract
    In the present study, the simulation of incompressible Electro-Magneto-hydrodynamic flows is performed using a finite volume lattice Boltzmann method (FVLBM). The Boltzmann transport equation is solved using a cell-centered finite volume method on structured meshes. A central difference scheme is used to discretize the spatial derivatives and the fourth-order numerical dissipation term is added to stabilize the solution. To discretize the temporal derivative, the fourth-order Runge-Kutta time stepping scheme is applied. The standard collision-streaming lattice Boltzmann method has been used to simulate EMHD flows in the literature, however, it has several deficiencies such as the... 

    Development of Finite Volume Method for Coupled Radiative, Convective, and Conductive Heat Transfer in Participating Media

    , Ph.D. Dissertation Sharif University of Technology Abrar, Bagher (Author) ; Darbandi, Masoud (Supervisor)
    Abstract
    Numerical simulations of participating media need careful solution of the radiation transfer equation (RTE) along the fluid flow governing equations. Evidently, the accuracy of achieved solutions highly depends on the accuracy of radiation transfer calculations. Despite numerous efforts performed in the previous researches, the RTE calculation still faces with several challenges from both accuracy and computational cost perspectives. The main objective of this research is to present new contributions in overcoming such challenges. So, a finite-volume (FV) solver is suitably developed to solve the RTE numerically. This extended solver is then coupled with an existing FV flow solver. The... 

    Investigation of Non-fourier Heat Transfer Model During Laser Irradiation in Teeth

    , M.Sc. Thesis Sharif University of Technology Zera'at Pisheh, Milad (Author) ; Nuri Boroujerdi, Ali (Supervisor) ; Arjmand, Navid (Supervisor)
    Abstract
    In the present study, the thermal behavior of human teeth during laser radiation has been discussed. The high laser power, as well as its low emission, can allow deviations from the Fourier heat transfer model. To overcome this problem, the non- Fourier heat transfer method, dual phase lagged (DPL), has been used. Wisdom considered in this study to evaluate the thermal behavior of tooth. Using the finite volume method, the DPL equations are solved and the thermal response of the teeth is obtained during laser irradiation. The effect of delay times, which are the parameters of the DPL model and depart from the Fourier model, is fully demonstrated on the temperature behavior of the tooth, and... 

    Develop the Multigrid Method to Solve the Hydrodynamics Problems

    , M.Sc. Thesis Sharif University of Technology PourMostafa, Mahdi (Author) ; Noori, Ali (Supervisor) ; Seif, Mohammad Saeed (Supervisor)
    Abstract
    In recent years, many advanced Computational Fluid Dynamics (CFD) methods have been developed for accurate and efficient simulation of fluid flow. The application of these methods shows that for sufficient accuracy, the mesh resolution has to be reasonably high. Unfortunately, conventioanal single-grid Navier-Stokes solvers suffer from poor convergence characteristics. For this problem we used Multigrid method to speed up the convergence rate. In this section a code was developed (based on the conventional CFD algorithm) which can solve Navier-Stokes equations on structured grids. It also simulates the free surface by VOF method. Agglomeration multigrid method is used in present study for... 

    Numerical Modeling of Pulse Tube Refrigerator and Study of Multi-Dimensional Effect

    , M.Sc. Thesis Sharif University of Technology Jahanbakhshi, Reza (Author) ; Saeedi, Mohammad Hassan (Supervisor)
    Abstract
    Pulse Tube Refrigerator (PTR) has an exceptional feature among all similar refrigerators, because of its unique characteristics such as long lifetime, compact size and no moving parts in low temperature. Despite of all these advantages because of its low efficiency, many researchers are trying to optimize performance of this refrigerator. Most of these efforts are based on one-dimensional simulation of the system. In this thesis, a two-dimensional analysis is performed to study the nature of flow field in an Inertance Tube Pulse Tube Refrigerator (ITPTR). This analysis is based on a numerical modeling of an entire ITPTR. To reach this purpose the two-dimensional form of mass, momentum and...