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    Recommendations on enhancing the efficiency of algebraic multigrid preconditioned GMRES in solving coupled fluid flow equations

    , Article Numerical Heat Transfer, Part B: Fundamentals ; Volume 55, Issue 3 , 2009 , Pages 232-256 ; 10407790 (ISSN) Vakili, S ; Darbandi, M ; Sharif University of Technology
    The algebraic multigrid (AMG) algorithm as a preconditioner to the Krylov subspace methods has drawn the attention of many researchers in solving fluid flow and heat transfer problems. However, the efficient employment of this solver needs experience, because users have to quantify several important parameters. In this work, we choose a hybrid finite-volume element method and quantify the optimum magnitudes for those parameters. To generalize our results, two sets of fluid flow governing equations, the thermobuoyant flow and confined diffusion flame, are studied and the optimum values are determined. The results indicate that the AMG can be very effective if a proper storage method is chosen... 

    Simulation of Fluid Flow on Superhydrophobic Surfaces

    , M.Sc. Thesis Sharif University of Technology Abdollahzadeh, Mohammad Javad (Author) ; Moosavi, Ali (Supervisor)
    Today, with rapid developments and advances in science and technology, different ways have been studied to reduce energy consumption in various industries. Reducing the drag force and thus reducing the friction force is one of these methods which has many applications (e. g, in submarine construction industries). Creating some microgrooves in the microchannels is one of the most effective methods in order to reduce the friction force in microchannels that has recently been studied. In this method the air is trapped within the microgrooves and when the fluid (e. g, water) enters the channel passes over the trapped air within these microgrooves instead of touching the channel walls (solid... 

    Simulation of Fluid Flow in Porous Media with Pipe Flow Model

    , M.Sc. Thesis Sharif University of Technology Mostafanezhad Asl Marand, Shahaboddin (Author) ; Rouhani, Shahin (Supervisor)
    Understanding of how fluid flow through porous media has many application in industry like Water filters technology and Gravel dams. also it’s very important in oil industry in areas like oil tank engineering. For doing this important thing many peoples tried to find out how fluid flows through the porous media they already invented the various kind of models, .the model used in this thesise is called pipe flow model which people use this model before but what I did have a little difference I used random lattice which people did not paid attention to it so the result of this model will be more trustable and close to what happens in nature. The result of this simulation showed us that the... 

    Numerical modeling of two-phase fluid flow in deformable fractured porous media using the extended finite element method and an equivalent continuum model

    , Article Advances in Water Resources ; Volume 94 , August , 2016 , Pages 510–528 ; 03091708 (ISSN) Khoei, A. R ; Hosseini, N ; Mohammadnejad, T ; Sharif University of Technology
    Elsevier Ltd  2016
    In the present paper, a numerical model is developed based on a combination of the extended finite element method and an equivalent continuum model to simulate the two-phase fluid flow through fractured porous media containing fractures with multiple length scales. The governing equations involve the linear momentum balance equation and the flow continuity equation for each fluid phase. The extended finite element method allows for an explicit and accurate representation of cracks by enriching the standard finite element approximation of the field variables with appropriate enrichment functions, and captures the mass transfer between the fracture and the matrix. Due to the high computational... 

    Study of the effect of fluid flow on corrosion rate for simple carbon steel in aqueous solution using rotating disk electrode

    , Article 18th International Congress of Chemical and Process Engineering, CHISA 2008, Prague, 24 August 2008 through 28 August 2008 ; 2008 Bastani, D ; Mohagheghi, A ; Sharif University of Technology
    The influence of fluid flow on the corrosion of simple carbon steel ST37 (AISI 1020) in aqueous solution of Bandar-Abbas gas well was studied at 25°C under air-saturated condition. The mechanism and kinetic of corrosion in different hydrodynamic conditions were determined using a rotating disk electrode. Increasing the velocity of rotating disk ≤ 1000 rpm caused an augmentation in corrosion rate from 9.89 to 18.95 mill in./yr. Increasing the velocity beyond 1000 rpm changed the corrosion mechanism so that the activation polarization will control the corrosion process, and the variation in corrosion rates was due to various corrosion mechanisms rather than mass transfer of reactant component.... 

    A comparison of various routing protocols in Mobile Ad-hoc Networks (MANETs) with the use of Fluid flow simulation method

    , Article 4th International Conference on Wireless and Mobile Communications, ICWMC 2008, Athens, 27 July 2008 through 1 August 2008 ; 2008 , Pages 260-267 ; 9780769532745 (ISBN) Salehan, A ; Robatmili, M ; Abrishami, M ; Movaghar, A ; IARIA ; Sharif University of Technology
    One of the most important challenges in mobile Ad-hoc networks is simulation. The simulation of these networks based on the accessible simulation techniques, which are based on packet, is a demanding and time-consuming task. Moreover, with the complexity of the network and the increase in the numbers of the nodes, it is likely to take a long time. This is because these simulators, one by one, regard the acts of all moving packets in one part of the network, and process these acts as a series of events. Since the number of the events is high in this method, the simulation takes time. Nowadays, in wired networks, several methods have been suggested to lessen the time of simulation; one example... 

    Analysis of fluid flow in cylindrical microchannels subjected to uniform wall injection

    , Article 3rd ASME Integrated Nanosystems Conference - Design, Synthesis, and Applications, Pasadena, CA, 22 September 2004 through 24 September 2004 ; 2004 , Pages 139-146 ; 0791841774 (ISBN); 9780791841778 (ISBN) Layeghi, M ; ASME Nanotechnology Institute ; Sharif University of Technology
    American Society of Mechanical Engineers  2004
    Analytical analysis of fluid flow in cylindrical microchannels subjected to uniform wall injection at various Reynolds numbers is presented. The classical Navier-Stokes equations are used in the present study. Mathematically, using an appropriate change of variable, Navier-Stokes equations are transformed to a set of nonlinear ordinary differential equations. The governing equations are solved analytically using series solution method. The presented analytical results can be used for the prediction of velocity profiles and pressure drops in the cylindrical micro channels. The results are validated against available data in the literature and have shown good agreement. Copyright © 2004 by... 

    Inertial microfluidics: a method for fast prediction of focusing pattern of particles in the cross section of the channel

    , Article Analytica Chimica Acta ; Volume 1083 , 2019 , Pages 137-149 ; 00032670 (ISSN) Mashhadian, A ; Shamloo, A ; Sharif University of Technology
    Elsevier B.V  2019
    Inertial microfluidics is utilized as a powerful passive method for particle and cell manipulation, which uses the hydrodynamic forces of the fluid in the channel to focus particles in specific equilibrium positions in the cross section of the channel. To achieve high performance manipulation, knowledge of focusing pattern of particles in the cross section of channel is essential. In this paper, we propose a method to address this important issue. To this end, firstly inertial microfluidics is analyzed in rectangular cross section channels. The results indicate that fluid flow velocity and channel's cross-sectional profiles have great impacts on the forces exerted on particles. Next, these... 

    Numerical Simulation of Heat Transfer on Topographically Structured Surfaces

    , M.Sc. Thesis Sharif University of Technology Javanbakht, Mohammad Hossein (Author) ; Moosavi, Ali (Supervisor)
    Numerous three-dimensional models of laminar flow and heat transfer in rough microchannels are developed and analyzed numerically to compare the effect of roughness elements on the thermal and hydrodynamic characteristics. In these models, the rough surfaces are configured with rectangular, triangular and sinusoidal roughness elements. Here, the effects of the roughness height, roughness element width, roughness element pitch, channel separation, Reynolds number and both Newtonian and non-Newtonian fluid on pressure drop and heat transfer in rough microchannels are all investigated and discussed.H2 thermal boundary condition is considered for all peripheral walls and power law model also is... 

    Hydro-mechanical modeling of cohesive crack propagation in multiphase porous media using the extended finite element method

    , Article International Journal for Numerical and Analytical Methods in Geomechanics ; Volume 37, Issue 10 , July , 2013 , PP. 1247–1279 Mohammadnejad, T. (Toktam) ; Khoei, A. R. (Amir Reza) ; Sharif University of Technology
    In this paper, a numerical model is developed for the fully coupled hydro-mechanical analysis of deformable, progressively fracturing porous media interacting with the flow of two immiscible, compressible wetting and non-wetting pore fluids, in which the coupling between various processes is taken into account. The governing equations involving the coupled solid skeleton deformation and two-phase fluid flow in partially saturated porous media including cohesive cracks are derived within the framework of the generalized Biot theory. The fluid flow within the crack is simulated using the Darcy law in which the permeability variation with porosity because of the cracking of the solid skeleton... 

    Simulation of mould filling in lost foam casting process

    , Article International Journal of Cast Metals Research ; Volume 16, Issue 6 , 2003 , Pages 554-565 ; 13640461 (ISSN) Mirbagheri, S. M. H ; Ashuri, H ; Varahram, N ; Davami, P ; Sharif University of Technology
    Maney Publishing  2003
    In this investigation, an algorithm was developed to calculate the gas pressure at the melt/foam interface (gap) owing to degraded foam during mould filling in the lost foam casting process (LFC). The effect of back-pressure on mould filling was modelled using a new experimental function by the addition of a three-dimensional volume of fluid (3D-VOF) function. The molten flow and free surface were simulated using the solution algorithm-VOF (SOLA-VOF) numerical technique. To simulate the three-dimensional incompressible flow in the LFC, the pressure boundary conditions, heat transfer and foam gas pressure effect were modified. Finally, in order to verify the computational results of... 

    Mesoscopic rheological modeling of drilling fluids: Effects of the electrolyte

    , Article Journal of Petroleum Science and Engineering ; Volume 195 , 2020 Kariman Moghaddam, A ; Ramazani Saadatabadi, A ; Sharif University of Technology
    Elsevier B.V  2020
    Drilling fluid is a complex fluid, including base fluid and other materials, carrying out the vital functions during drilling operation such as cutting transport and controlling formation pressure. In order to optimize performance of a drilling process, a reliable rheological model is required in the computation of fluid flow dynamics. Time-independent Generalized Newtonian formulation are the most common models for describing the rheological behavior of drilling fluids due to its simplicity and ease of use, in spite the fact that they are not able to predict the normal stresses and could not consider effects of active components on the rheological behavior of the drilling fluid and also... 

    Heat transfer and fluid flow analysis of microchannel heat sinks with periodic vertical porous ribs

    , Article Applied Thermal Engineering ; Volume 205 , 2022 ; 13594311 (ISSN) Lori, M.S ; Vafai, K ; Sharif University of Technology
    Elsevier Ltd  2022
    In this study, a detailed numerical analysis of the fluid flow and heat transfer of a three-dimensional microchannel is performed to evaluate the effect of using periodic vertical porous and solid ribs with various geometrical shapes, including rectangular, elliptical, isosceles triangular, backward triangular and forward triangular on the walls of this microchannel. Darcy-Brinkman-Forchheimer equations are used to model transport through the porous medium. The results for microchannels with solid ribs and with porous ribs are compared to each other. It is found that at the lowest studied inlet velocity (uin=0.25m/s), for the rib heights of Hr=0.025mm,0.05mmand0.07mm, the average Nusselt... 

    Simulation of Fluid Flow Through Ceramic Foam Filters in Basis of Porous Media Permeability Properties

    , M.Sc. Thesis Sharif University of Technology Googajelou, Abbas (Author) ; Davomi, Parviz (Supervisor) ; Varahram, Naser (Supervisor)
    Real modeling of ceramic foam filters, because of their specific tortuosities is not possible and in case of possibility of real modeling of pores in filters, because of restriction of element’s dimensions, the number of elements increases and model can’t be run in a reasonable time with common computers which are accessible nowadays. The common computer simulation of filters in Computational Fluid Dynamic (CFD) and their effect on fluid flow pattern is done by use of permeability properties of porous media. In this research, ceramic foam filters which are used in casting are simulated by Forchhimer and Darcy models. SUT CAST software is used for simulation, because of its ability for... 

    Investigation and Simulation of near Wellbore Damage Effect on Reservoir Fluid Flow

    , M.Sc. Thesis Sharif University of Technology Shams, Mosayeb (Author) ; Jamshidi, Saeed (Supervisor) ; Pishvaei, Mahmood Reza (Co-Advisor)
    Many petroleum engineering operations, such as drilling, well completions, and workover, may cause an alteration in the properties of hydrocarbon-bearing formations, including porosity and permeability. Solid and fluid influx into the reservoir in an overbalanced pressure condition can cause permeability reduction from formation damage in the invaded zone. While the solid invasion is limited to a few inches away from the wellbore, the fluids will invade significantly deeper into the formation. Therefore, the invasion of fluids may be considered as the primary mechanism that causes the near-wellbore damage. Correct quantification of the damage is an important component for predicting well... 

    Qualitative Simulation of Fluid Flow in Reservoir Using Fuzzy Logic

    , M.Sc. Thesis Sharif University of Technology Ghadiri, Saber (Author) ; Pishvaie, Mahmoud Reza (Supervisor) ; Jamshidi, Saeed (Supervisor)
    Investigation of reservoir performance and long-term production prediction are main goal of numerical simulation. Numerical simulation mainly consists of solving sets of non-linear equations developed by combination of continuity equation, equation of state and Darcy equation. Classical methods such as finite difference method (FDM), finite volume method (FVM) and finite element method (FEM) are widely used for solving sets of fluid flow equations that mentioned above. Researchers have used other methods like boundary element method recently. Each of these methods has their own restrictions. But the main source of error in these methods is due to numerical estimation of spatial derivatives... 

    Methematical Modeling of Steady State Operation of A Loop Heat Pipe

    , M.Sc. Thesis Sharif University of Technology Mostafazade Abolmaali, Ali (Author) ; Shafii, Mohammad Behshad (Supervisor)
    Loop heat pipe (LHP) is a two phase heat transfer device that is mostly used in cooling spacecrafts facilities. In this research a novel LHP is studied analytically and its steady state operating characteristics is analyzed in a one dimensional approach with heat transfer and pressure drop correlations. The novel LHP has a new arrangement in evaporator and reservoir configuration in comparison with conventional LHPs, which results in a different energy and fluid flow. In addition, the novel LHP has a new mechanism for acive control of working temperature. In modeling the proposed LHP the fluid and energy flows are first determined, then proper correltaions for calculationg each energy flow... 

    Investigating the Dispersion Phenomenon in Fluid Flow through Porous Media Using Percolation Theory

    , M.Sc. Thesis Sharif University of Technology Keybondorian, Ebrahim (Author) ; Masihi, Mohsen (Supervisor) ; Ganjeh Ghazvini, Mostafa (Co-Advisor)
    Many processes in the petroleum engineering industry involve particle transport in oil and gas reservoirs including sand production, fines migration, and nanoparticle injection. In these processes it is important to understand where the particles are travelling in the reservoir and the impact that they have on the formation properties. Large particles can damage the formation and decrease permeability which reduces the productive capacity of the reservoir. During nanoparticle injection, forces at the pore level can cause retention of particles and prevent their recovery. In addition, due to the heterogeneity of typical reservoirs, it is difficult to predict how particles will spread across... 

    Cutting Transport Modelling Using Lattice Boltzmann Method

    , M.Sc. Thesis Sharif University of Technology Soleymanpour, Javad (Author) ; Jamshidi, Saeed (Supervisor)
    Transport of drilling cuttings at the bottom of the well has always been one of the common problems of oil and gas drilling, which causes stock pipe or reduce the penetration rate and other problem. For this reason, the design of drilling fluid is one of the important drilling problems to be considered in order to optimally transfer drilling cuttings to surface. So far, many papers have been devoted to optimizing the drilling fluid for the transport of cuttings, but these papers focus on the state of drilling fluid static and less to model the dynamics and to examine the interaction between the cuttings and drilling fluid. At this end this study will modeling the drilling fluid flow using... 

    Nonlinear Vibrations of Conical Shells with Concurrent Internal and External Flows

    , Ph.D. Dissertation Sharif University of Technology Rahmanian, Mohammad (Author) ; Dehghani Firouz Abadi, Ruhollah (Supervisor)
    In the current study, nonlinear vibration and stability of conical shells with both separate and concurrent internal and external flows are studied. External and internal flows are in the supersonic and subsonic regimes, respectively. The Krumhar’s aerodynamic piston theory is utilized to model the external loading on the structure as well as the compressible potential flow model to capture the internal fluid dynamics. The so-called compressible fluid model is obtained via simplification of the Navier-Stockes equations after applying the inviscid and irrotational assumptions. The nonlinear structural equations of motion are derived using the Hamiltonian dynamics approach and utilizing the...