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    Modification of compressible smooth particles hydrodynamics for angular momentum in simulation of impulsive wave problems

    , Article Prediction and Simulation Methods for Geohazard Mitigation - Proceedings of the International Symposium on Prediction and Simulation Methods for Geohazard Mitigation, IS-KYOTO 2009, 25 May 2009 through 27 May 2009 ; 2009 , Pages 201-206 ; 9780415804820 (ISBN) Mansour Rezaei, S ; Ataie Ashtiani, B ; Sharif University of Technology
    Abstract
    In this work, Compressible Smooth Particles Hydrodynamics (C-SPH) is applied for numerical simulation of impulsive wave. Properties of linear and angular momentum in SPH formulation are studied. Kernel gradient of viscous term in momentum equation is corrected to ensure preservation of angular momentum. Corrected SPH method is used to simulate solitary Scott Russell wave and applied to simulate impulsive wave generated by two-dimensional under water landslide. In each of test cases, results of corrected SPH are compared with experimental results. The results of the numerical simulations and experimental works are matched and a satisfactory agreement is observed. Furthermore, vorticity... 

    Analytical solution for penetration of deformable blunt projectiles into the metallic targets

    , Article Mechanika ; Volume 82, Issue 2 , 2010 , Pages 5-13 ; 13921207 (ISSN) Radmehr, D ; Liaghat, G. H ; Felli, S ; Naderi, D ; Sharif University of Technology
    2010
    Abstract
    At the present research, a new analytical model is developed for the impact of a deformable blunt projectile to metallic targets using the plastic stress wave propagation theory and the momentum equations. At this model, the deformation of the projectile is considered, too. Also, the effects of dishing and plugging phenomena on failure of the target are investigated. All of the obtained results are compared with the experimental and other available analytical results where good agreement has been observed. The other outcome of this research is a new definition for the penetration stages which includes 9 ones. Motion equations are derived for each of these stages, accordingly  

    Numerical investigation of steady density currents flowing down an incline using v2̄ - F turbulence model

    , Article Journal of Fluids Engineering, Transactions of the ASME ; Volume 129, Issue 9 , 2007 , Pages 1172-1178 ; 00982202 (ISSN) Khakzad, N ; Firoozabadi, B ; Farhanieh, B ; Sharif University of Technology
    2007
    Abstract
    The governing equations of two-dimensional steady density currents are solved numerically using a finite volume method. The v2̄-f turbulence model, based on standard k - s model, is used for the turbulence closure. In this method, all Reynolds stress equations are replaced with both a transport equation for v2̄ and an elliptic relaxation equation for f, a parameter closely related to the pressure strain redistribution term. The Simple-C procedure is used for pressure-velocity coupling. In addition, Boussinesq's approximation is used to obtain the momentum equation. The computed height of the progressive density current is compared to the measured data in the literature, resulting in good... 

    Investigation of dynamics and vibration of PIG in oil and gas pipelines

    , Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 9 PART C , 2008 , Pages 2015-2024 ; 0791843033 (ISBN); 9780791843031 (ISBN) Durali, M ; Fazeli, A ; Nabi, A ; Sharif University of Technology
    2008
    Abstract
    In this paper, the transient motion of an intelligent Pipe Inspection Gauge (PIG) while moving across anomalies inside a typical gas/oil pipeline has been investigated. The pipeline fluid has been considered as isothermal and compressible. In addition, the pipeline itself has also been considered to be flexible. The fluid continuity and momentum equations along with the 3D dynamic equations of motion of the pig comprise a system of coupled dynamic differential equations which have been solved numerically. Pig's position, orientation and velocity profiles as well as upstream and downstream fluid's pressure waves are presented as simulation results which provide a better understanding of the... 

    Thermal-hydraulic analysis of HPLWR fuel assembly cluster

    , Article Journal of Supercritical Fluids ; Volume 77 , May , 2013 , Pages 91-99 ; 08968446 (ISSN) Tashakor, S ; Salehi, A. A ; Jahanfarnia, G ; Sharif University of Technology
    2013
    Abstract
    The High-Performance Light Water Reactor (HPLWR) is the European version of the Supercritical-pressure Water Cooled Reactor (SCWR). Light water reactors at supercritical pressure, being currently under design, are the new generation of nuclear reactors. The present article is a thermal-hydraulic analysis of the HPLWR fuel assembly cluster. The existing thermal hydraulic codes are not capable of analyzing and designing the HPLWR fuel assembly. It is necessary to introduce a new thermal-hydraulic code that can incorporate the parameters and specifications of the HPLWR fuel assembly. The governing equations include energy, mass and momentum equations beside thermal-hydraulic equations are... 

    Selection and simulation of a proper microfluidic for hepatocyte culture

    , Article 2015 22nd Iranian Conference on Biomedical Engineering, ICBME 2015, 25 November 2015 through 28 November 2015 ; 2015 , Pages 65-69 ; 9781467393515 (ISBN) Nejadnasrollah, F ; Firoozabadi, B ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    The advent of microfluidics as suitable environments for culturing cells is associated with some challenges as shear stresses applied on the cells. Moreover, among all factors needed for cell viability, feeding hepatocytes with adequate oxygen is of great importance due to their high demand for oxygen compared the other cell types. In this paper three kinds of geometries has been studied in order that shear stresses would be in allowed range and provision of hepatocytes with sufficient oxygen concentrations has been ensured as well. In addition to supplying hepatocytes with oxygen, the range of its concentration has been adjusted in physiologic value so that it would be practical for further... 

    Modification of weakly compressible smoothed particle hydrodynamics for preservation of angular momentum in simulation of impulsive wave problems

    , Article Coastal Engineering Journal ; Volume 51, Issue 4 , 2009 , Pages 363-386 ; 05785634 (ISSN) Ataie Ashtiani, B ; Mansour Rezaei, S ; Sharif University of Technology
    Abstract
    In this work, Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) is applied for numerical simulation of impulsive wave. Properties of linear and angular momentum in WCSPH formulation are studied. Kernel gradient of viscous term in momentum equation is corrected to ensure preservation of angular momentum. Corrected WCSPH method is used to simulate solitary Scott Russell wave and applied to simulate impulsive wave generated by two-dimensional under water landslide. In each of the test cases, results of corrected WCSPH are compared with experimental results. The results of the numerical simulations and experimental works are matched and a satisfactory agreement is observed.... 

    Analysis of micropolar elastic beams

    , Article European Journal of Mechanics, A/Solids ; Volume 28, Issue 2 , 2009 , Pages 202-208 ; 09977538 (ISSN) Ramezani, S ; Naghdabadi, R ; Sohrabpour, S ; Sharif University of Technology
    2009
    Abstract
    In this paper, a linear theory for the analysis of beams based on the micropolar continuum mechanics is developed. Power series expansions for the axial displacement and micro-rotation fields are assumed. The governing equations are derived by integrating the momentum and moment of momentum equations in the micropolar continuum theory. Body couples and couple stresses can be supported in this theory. After some simplifications, this theory can be reduced to the well-known Timoshenko and Euler-Bernoulli beam theories. The nature of flexural and longitudinal waves in the infinite length micropolar beam has been investigated. This theory predicts the existence of micro-rotational waves which... 

    Solution of the falkner-skan equation for wedge by adomian decomposition method

    , Article Communications in Nonlinear Science and Numerical Simulation ; Volume 14, Issue 3 , 2009 , Pages 724-733 ; 10075704 (ISSN) Alizadeh, E ; Farhadi, M ; Sedighi, K ; Ebrahimi Kebria, H. R ; Ghafourian, A ; Sharif University of Technology
    2009
    Abstract
    The Adomian Decomposition Method is employed in the solution of the two dimensional laminar boundary layer of Falkner-Skan equation for wedge. This work aims at the solution of momentum equation in the case of accelerated flow and decelerated flow with separation. The Adomian Decomposition Method is provided an analytical solution in the form of an infinite power series. The effect of Adomian polynomials terms is considered on accuracy of the results. The velocity profiles in boundary layer are obtained. Results show a good accuracy compared to the exact solution. © 2007 Elsevier B.V. All rights reserved  

    Investigation of dynamics and vibration of a three unit pig in oil and gas pipelines

    , Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 265-275 ; 9780791848722 (ISBN) Durali, M ; Fazeli, A ; Azimi, M ; Sharif University of Technology
    2009
    Abstract
    In this paper, the transient motion of a three unit intelligent Pipe Inspection Gauge (PIG) while moving across anomalies and bends inside gas/oil pipeline has been investigated. The pipeline fluid has been considered as isothermal and compressible. In addition, the pipeline itself has also been considered to be flexible. The fluid continuity and momentum equations along with the 3D multi body dynamic equations of motion of the pig comprise a system of coupled dynamic differential equations which have been solved numerically. Pig's position and velocity profiles as well as upstream and downstream fluid's pressure waves are presented as simulation results which provide a better understanding... 

    Numerical simulation of density current using two-phase flow

    , Article 2006 2nd ASME Joint U.S.-European Fluids Engineering Summer Meeting, FEDSM 2006, Miami, FL, 17 July 2006 through 20 July 2006 ; Volume 2006 , 2006 ; 0791837831 (ISBN); 9780791837832 (ISBN) Afshin, H ; Firoozabadi, B ; Sharif University of Technology
    2006
    Abstract
    Due to shear layer at the interface of density current and ambient fluid, density current disturbs and entrains the surrounding fluid. Most existing analytical and numerical models for density current flows are based on the equations for single-phase flows. In this research, the density current has been modeled with two-phase flow model. The governing equations are continuity, x- momentum, and y- momentum equations for every fluid. The volume-of-fluid (VOF) interface tracking technique which uses a piecewise-linear interface calculation (PLIC) in each cell is used to determine the deformation of free surface in density current, numerically. Surface tension is implemented by the continuous... 

    Electroosmotic flow of power-law fluids with temperature dependent properties

    , Article Journal of Non-Newtonian Fluid Mechanics ; Volume 185-186 , 2012 , Pages 49-57 ; 03770257 (ISSN) Babaie, A ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology
    Elsevier  2012
    Abstract
    The influence of variable fluid properties on mixed electroosmotic and pressure driven flow of non-Newtonian fluids is investigated in this paper. The non-linear coupled energy and momentum equations are solved by means of an iterative numerical approach. The results reveal that the temperature dependent effects only become significant at very high values of the Debye-Hückel parameter in case of combined electroosmotic and pressure driven flow and could safely be neglected in other cases. It is observed that the physical properties variation lead to a higher mean velocity in case of pressure assisted flow and a lower mean velocity in case of pressure opposed flow. Furthermore, the... 

    Transient behavior of fluid flow and heat transfer in vertical channels partially filled with porous medium: Effects of inertial term and viscous dissipation

    , Article Energy Conversion and Management ; Volume 61 , September , 2012 , Pages 1-7 ; 01968904 (ISSN) Hajipour, M ; Molaei Dehkordi, A ; Sharif University of Technology
    Elsevier  2012
    Abstract
    In this article, transient hydrodynamic and heat-transfer behavior of Newtonian fluid flow in vertical parallel-plate channels partially filled with a porous medium has been investigated numerically. In this regard, the influences of macroscopic local inertial term and the viscous heating due to the viscous dissipation were taken into account in the momentum equations of porous region and the thermal energy equations, respectively. Moreover, Forchheimer-Brinkman extended Darcy model was used to model fluid flow in the porous region. In addition, an analytical solution was obtained in the case of negligible Brinkman and Forchheimer number values at the steady-state conditions. The predicted... 

    Optimization assisted asphaltene deposition modeling in porous media during a natural depletion scheme

    , Article Petroleum Science and Technology ; Volume 30, Issue 9 , Mar , 2012 , Pages 958-965 ; 10916466 (ISSN) Hematfar, V ; Bagheri, M ; Kharrat, R ; Ghazanfari, M ; Ghotbi, C ; Sharif University of Technology
    2012
    Abstract
    Changes in thermodynamic properties such as pressure, temperature, and composition may result in asphaltene precipitation and deposition in porous media. In addition, asphaltene deposition can cause wettability alteration, permeability reduction, and ultimately a decrease in the productivity of a reservoir. Natural depletion is one of the most common processes of asphaltene deposition in which pressure changes destabilize the dissolved asphaltene in the oil and settle them onto the rock surface. In this work, natural depletion experiments in consolidated core samples were performed under simulated reservoir conditions to obtain reliable data and analyze the asphaltene deposition mechanisms.... 

    Combined electroosmotically and pressure driven flow of power-law fluids in a slit microchannel

    , Article Journal of Non-Newtonian Fluid Mechanics ; Volume 166, Issue 14-15 , August , 2011 , Pages 792-798 ; 03770257 (ISSN) Babaie, A ; Sadeghi, A ; Saidi, M. H ; Sharif University of Technology
    2011
    Abstract
    Electroosmotic flow of power-law fluids in the presence of pressure gradient through a slit is analyzed. After numerically solving the Poisson-Boltzmann equation, the momentum equation with electroosmotic body force is solved through an iterative numerical procedure for both favorable and adverse pressure gradients. The results reveal that, in case of pressure assisted flow, shear-thinning fluids reach higher velocity magnitudes compared with shear-thickening fluids, whereas the opposite is true when an adverse pressure gradient is applied. The Poiseuille number is found to be an increasing function of the dimensionless Debye-Hückel parameter, the wall zeta potential, and the flow behavior... 

    Modeling and optimization of asphaltene deposition in porous media using genetic algorithm technique

    , Article Society of Petroleum Engineers - International Oil and Gas Conference and Exhibition in China 2010, IOGCEC, 8 June 2010 through 10 June 2010 ; Volume 1 , June , 2010 , Pages 479-491 ; 9781617388866 (ISBN) Hematfar, V ; Kharrat, R ; Ghazanfari, M. H ; Bagheri, M. B ; Sharif University of Technology
    2010
    Abstract
    Different models have been proposed for deposition of asphaltene on reservoir rocks that due to complexity of asphaltene nature, most of them have not been productive. Here, a reliable model is proposed which despite of previous models, considers the change in asphaltene saturation in the core. The obtained experimental data in the laboratory was used for model validation. In this work, a series of core flooding tests was carried out in presence of connate water at different solvent-oil volume ratios. Pressure drop was measured at three different terminals along the core. The obtained experimental data as well as mass balance equations, momentum equation, asphaltene deposition and... 

    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  

    Electrokinetically driven fluidic transport of power-law fluids in rectangular microchannels

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 414 , 2012 , Pages 440-456 ; 09277757 (ISSN) Vakili, M. A ; Sadeghi, A ; Saidi, M. H ; Mozafari, A. A ; Sharif University of Technology
    2012
    Abstract
    Electroosmosis is the predominant mechanism for flow generation in lab-on-chip devices. Since most biofluids encountered in these devices are considered to be non-Newtonian, it is vital to study the flow characteristics of common non-Newtonian models under electroosmotic body force. In this paper, the hydrodynamically fully developed electroosmotic flow of power-law fluids in rectangular microchannels is analyzed. The electrical potential and momentum equations are numerically solved through a finite difference procedure for a non-uniform grid. A thoroughgoing parametric study reveals that the Poiseuille number is an increasing function of the channel aspect ratio, the zeta potential, the... 

    Dynamic modeling and optimization of asphaltene deposition in reservoir rocks using genetic algorithm

    , Article 72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 ; Volume 6 , 2010 , Pages 4291-4295 ; 9781617386671 (ISBN) Bagheri, M. B ; Kharrat, R ; Hemmatfar, V ; Ghotbi, C ; Sharif University of Technology
    Society of Petroleum Engineers  2010
    Abstract
    Asphaltene deposition is a problematic challenge for oil production. Changes in key parameters like pressure and fluid composition during natural depletion and different gas injection scenarios may result in asphaltene precipitation and deposition. In this work, a model is developed by application of mass balance equations, momentum equation, asphaltene deposition and permeability reduction models. An algorithm is developed to perform iterative procedure to solve the numerical equations that contains highly coupled variables. Indeed, an equation is introduced to calculate the saturation of the precipitated asphaltene phase. Model parameters were determined by genetic algorithm which is a...