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    Numerical simulation of buoyancy affected turbulent air flow in a room

    , Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) Nouri Borujerdi, A ; Fathi Gishnegani, A ; Sharif University of Technology
    American Society of Mechanical Engineers  2006
    Abstract
    In this paper a three-dimensional steady state incompressible turbulent air flow is considered in a large single room. The buoyancy affected turbulent air flow is simulated by solving governing equations numerically. The turbulence modeling includes both k - ε and zero-equation models and their results are compared to the experimental data. The paper reviews several aspects such as displacement of radiator system performance, temperature and flow field distribution and comfort. The results show that the best temperature distribution and comfort obtain when radiator is installed under the window and its height be equal to or greater than that of the window. Copyright © 2006 by ASME  

    Experimental study of three-dimensional flow field around a complex bridge pier

    , Article Journal of Engineering Mechanics ; Volume 136, Issue 2 , 2010 , Pages 143-154 ; 07339399 (ISSN) Beheshti, A. A ; Ataie Ashtiani, B ; Sharif University of Technology
    2010
    Abstract
    In this paper, three-dimensional turbulent flow field around a complex bridge pier placed on a rough fixed bed is experimentally investigated. The complex pier foundation consists of a column, a pile cap, and a 2×4 pile group. All of the elements are exposed to the approaching flow. An acoustic-Doppler velocimeter was used to measure instantaneously the three components of the velocities at different horizontal and vertical planes. Profiles and contours of time-averaged velocity components, turbulent intensity components, turbulent kinetic energy, and Reynolds stresses, as well as velocity vectors are presented and discussed at different vertical and horizontal planes. The approaching... 

    Computational Investigation of Primary Atomization of an Unsteady and 3D Laminar Liquid Jet, Using LBM and GPU

    , M.Sc. Thesis Sharif University of Technology Shadkhah, Mehdi (Author) ; Taeibi, Mohammad (Supervisor) ; Kebriaee, Azadeh (Co-Supervisor) ; Salimi, Mohammad Reza (Co-Supervisor)
    Abstract
    Based on the history of computational fluid dynamics, choosing a proper method for three-dimensional investigation of two-phase flows is always challenging. In this research, the flow of atomization of a liquid jet was investigated. Also, Using GPU technique made our computations about 40 times faster. The numerical results are in good agreement with available numerical and experimental data. Based on our results, jet flow can achieve different regimes at different Weber and Reynold. Jet flow was found in dripping and Rayleigh instability regimes when Weber number was set to 1.79 and 3.10, respectively. Also, the transition between dripping and jetting was estimated at We between 2 to 3. In... 

    Investigation on effect of centrifugal compressor volute cross-section shape on performance and flow field

    , Article Proceedings of the ASME Turbo Expo ; Volume 8, Issue PARTS A, B, AND C , 2012 , Pages 871-880 ; 9780791844748 (ISBN) Mojaddam, M ; Benisi, A. H ; Movahhedy, M. R ; Sharif University of Technology
    2012
    Abstract
    In this article, the effects of volute cross section shape and centroid profile of a centrifugal compressor volute were investigated. The performance characteristics of a turbocharger compressor were obtained experimentally by measuring rotor speed and flow parameters at the inlet and outlet of the centrifugal compressor. The three dimensional flow field model of the compressor was obtained numerically solving Navier- Stokes equations with SST turbulence model. The compressor characteristic curves were plotted. For model verification, the results were compared with experimental data, showing good agreement. Modification of a volute was performed by introducing a shape factor for volute cross... 

    Characteristic variables and entrainment in 3-D density currents

    , Article Scientia Iranica ; Volume 15, Issue 5 , 2008 , Pages 575-583 ; 10263098 (ISSN) Hormozi, S ; Firoozabadi, B ; Ghasvari Jahromi, H ; Sharif University of Technology
    Sharif University of Technology  2008
    Abstract
    A CFD code has been developed to describe the salt solution density current, which propagates three-dimensionally in deep ambient water. The height and width of the dense layer are two dominated length scales in a 3-D structure of the density current. In experimental efforts, it is common to measure the height and width of this current via its brightness. Although there are analytical relations to calculate the current height in a two-dimensional flow, these relations cannot be used to identify the width and height of a 3-D density current, due to the existence of two unknown parameters. In the present model, the height and width of the dense layer are obtained by using the boundary layer... 

    Experimental & numerical investigation of a centrifugal compressor and numerical study of the area ratio and tip clearance effects on the performance characteristic

    , Article 2008 ASME Turbo Expo, Berlin, 9 June 2008 through 13 June 2008 ; Volume 6, Issue PART B , 2008 ; 9780791843161 (ISBN) Nili Ahmadabadi, M ; Hajilouy Benisi, A ; Durali, M ; Motavalli, S. M ; Sharif University of Technology
    American Society of Mechanical Engineers(ASME)  2008
    Abstract
    In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and diffuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was... 

    Simulation of an innovative flow-field design based on a bio inspired pattern for PEM fuel cells

    , Article Renewable Energy ; Volume 41 , 2012 , Pages 86-95 ; 09601481 (ISSN) Roshandel, R ; Arbabi, F ; Moghaddam, G. K ; Sharif University of Technology
    2012
    Abstract
    Proton exchange membrane (PEM) fuel cell performance is directly related to the bipolar plate design and their channels pattern. Power enhancements can be achieved by optimal design of the type, size, or patterns of the channels. It has been realized that the bipolar plate design has significant role on reactant transport as well as water management in a PEM Fuel cell. Present work concentrates on improvements in the fuel cell performance by optimization of flow-field design and channels configurations. A three-dimensional, multi-component numerical model of flow distribution based on Navier-Stokes equations using individual computer code is presented. The simulation results showed excellent... 

    Effect of different configurations on 3-D analysis of flow through stay vanes And guide vanes of a francis turbine

    , Article Scientia Iranica ; Volume 17, Issue 6 B , NOVEMBER-DECEMBER , 2010 , Pages 419-432 ; 10263098 (ISSN) Dadfar, R ; Firoozabadi, B ; Ahmadi, G ; Sharif University of Technology
    2010
    Abstract
    Stay and guide vanes (distributor) are essential parts of a turbine. They are used to control the flow rate and to appropriately transfer the flow momentum to the runner. In this work, flow through the distributor is analyzed. For various Boundary Conditions (BC) and different configurations, threedimensional flows in the distributor of a Francis turbine are evaluated and compared with each other. The numerical simulations were carried out using Fluent software and the results were validated with a GAMM Francis turbine, where the geometry and detailed best efficiency measurements were publically available. In these simulations, the flow was assumed to be steady and the effect of turbulence... 

    Application of the adjoint optimisation of shock control bump for ONERA-M6 wing

    , Article European Journal of Computational Mechanics ; Volume 26, Issue 5-6 , 2017 , Pages 557-583 ; 17797179 (ISSN) Nejati, A ; Mazaheri, K ; Sharif University of Technology
    Abstract
    This article is devoted to the numerical investigation of the shock wave/boundary layer interaction (SWBLI) as the main factor influencing the aerodynamic performance of transonic bumped airfoils and wings. The numerical analysis is conducted for the ONERA-M6 wing through a shock control bump (SCB) shape optimisation process using the adjoint optimisation method. SWBLI is analyzed for both clean and bumped airfoils and wings, and it is shown how the modified wave structure originating from upstream of the SCB reduces the wave drag, by improving the boundary layer velocity profile downstream of the shock wave. The numerical simulation of the turbulent viscous flow and a gradient-based adjoint... 

    Characterization of three-phase flow in porous media using the ensemble Kalman filter

    , Article Scientia Iranica ; Volume 24, Issue 3 , 2017 , Pages 1281-1301 ; 10263098 (ISSN) Jahanbakhshi, S ; Pishvaie, M. R ; Bozorgmehry Boozarjomehry, R ; Sharif University of Technology
    Sharif University of Technology  2017
    Abstract
    In this study, the ensemble Kalman filter is used to characterize threephase flow in porous media through simultaneous estimation of three-phase relative permeabilities and capillary pressures from production data. Power-law models of relative permeability and capillary pressure curves are used and the associated unknown parameters are estimated by assimilating the measured historical data. The estimation procedure is demonstrated on a twin numerical setup with two different scenarios, in which a synthetic 2D reservoir under three-phase flow is considered. In the first scenario, all the endpoints are assumed to be known and only the shape factors are estimated during the assimilation... 

    Effect of permeability heterogeneity on the dissolution process during carbon dioxide sequestration in saline aquifers: two-and three-dimensional structures

    , Article Geomechanics and Geophysics for Geo-Energy and Geo-Resources ; Volume 8, Issue 2 , 2022 ; 23638419 (ISSN) Mahyapour, R ; Mahmoodpour, S ; Singh, M ; Omrani, S ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    Abstract: The convection–diffusion process of carbon dioxide (CO2) dissolution in a saline reservoir is investigated to shed light on the effects of the permeability heterogeneity. Using sequential Gaussian simulation method, random permeability fields in two and three-dimension (2D and 3D) structures are generated. Quantitative (average amount of the dissolved CO2 and dissolution flux) and qualitative (pattern of the dissolved CO2 and velocity streamlines) measurements are used to investigate the results. A 3D structure shows a slightly higher dissolution flux than a 2D structure in the homogeneous condition. Results in the random permeability fields in 2D indicates an increase in the... 

    Numerical modeling of multiphase fluid flow in deforming porous media: A comparison between two- and three-phase models for seismic analysis of earth and rockfill dams

    , Article Computers and Geotechnics ; Volume 38, Issue 2 , March , 2011 , Pages 142-166 ; 0266352X (ISSN) Khoei, A. R ; Mohammadnejad, T ; Sharif University of Technology
    Abstract
    In this paper, a fully coupled numerical model is presented for the finite element analysis of the deforming porous medium interacting with the flow of two immiscible compressible wetting and non-wetting pore fluids. The governing equations involving coupled fluid flow and deformation processes in unsaturated soils are derived within the framework of the generalized Biot theory. The displacements of the solid phase, the pressure of the wetting phase and the capillary pressure are taken as the primary unknowns of the present formulation. The other variables are incorporated into the model using the experimentally determined functions that define the relationship between the hydraulic... 

    A sequential implicit discrete fracture model for three-dimensional coupled flow-geomechanics problems in naturally fractured porous media

    , Article Journal of Petroleum Science and Engineering ; Volume 150 , 2017 , Pages 312-322 ; 09204105 (ISSN) Moradi, M ; Shamloo, A ; Dezfuli, A. D ; Sharif University of Technology
    Abstract
    A sequential implicit numerical method based on discrete-fracture model and the Galerkin Finite Element method, for time-dependent coupled fluid flow and geomechanics problems in fractured subsurface formations is presented. Discrete-fracture model has been used to explicitly represent the fracture network inside porous media. The Galerkin Finite Element method with adaptive unstructured gridding is implemented to numerically solve the spatially three-dimensional and time-dependent problem. The presented method is validated with previously obtained solutions. Two problems are numerically solved by applying the presented methodology in a three-dimensional fractured petroleum reservoir under... 

    Numerical investigation of fluid flow and heat transfer characteristics in parallel flow single layer microchannels

    , Article Scientia Iranica ; Volume 16, Issue 4 B , 2009 , Pages 313-331 ; 10263098 (ISSN) Asgari, O ; Saidi, M. H ; Sharif University of Technology
    2009
    Abstract
    Heat generation from Very Large-Scale Integrated (VLSI) circuits increases with the development of high-density integrated circuit technology. One of the efficient techniques is liquid cooling by using a microchannel heat sink. Numerical simulations on the microchannel heat sink in the literature are mainly two dimensional. The purpose of the present study is to develop a three-dimensional procedure to investigate flow and conjugate heat transfer in the microchannel heat sink for electronic packaging applications. A finite volume numerical code with a multigrid technique, based on an additive correction multigrid (AC-MG) scheme, which is a high-performance solver, is developed to solve the... 

    Effect of different geometries in simulation of 3D viscous flow in francis turbine runners

    , Article Scientia Iranica ; Volume 16, Issue 4 B , 2009 , Pages 363-369 ; 10263098 (ISSN) Firoozabadi, B ; Dadfar, R ; Pirali, A. P ; Ahmadi, G ; Sharif University of Technology
    2009
    Abstract
    Overall turbine analysis requires large CPU time and computer memory, even in the present days. As a result, choosing an appropriate computational domain accompanied by a suitable boundary condition can dramatically reduce the time cost of computations. This work compares different geometries for numerical investigation of the 3D flow in the runner of a Francis turbine, and presents an optimum geometry with least computational effort and desirable numerical accuracy. The numerical results are validated with a GAMM Francis Turbine runner, which was used as a test case (GAMM workshop on 3D computation of incompressible internal flows, 1989) in which the geometry and detailed best efficiency...