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    Application and evaluation of RUSLE erosion model in JAJROOD watershed (ROODAK) with G.I.S

    , Article Proceedings of the 2nd IASTED International Conference on Environmental Management and Engineering, EME 2010, 15 July 2010 through 17 July 2010, Banff, AB ; July , 2010 , Pages 879-887 ; 9780889868526 (ISBN) Mirzai, M ; Sajadi, A ; Nazari, A ; Sharif University of Technology
    In this study amount of soil erosion in watershed of JAJROOD is estimated by use of the RULSE model with the help of GIS12. JAJROOD River is located in upstream of LATIAN Dam and is one of the most important water sources of Tehran. Also, this River has a big role in preventing the flood. modeling Results show that the amount of soil erosion is high due to high slope of the land, lack of plant coverage and the quality of soil and changing the land application, lead to increase in erosion potential. modeling Results have estimated the amount of erosion in this basin about 1,524,511 tons in a year. In order to evaluate Results and efficiency of the model, all of obtained results are compared... 

    Scouring Contol by Submerged Vanes at 90° Open-Channel Junctions

    , M.Sc. Thesis Sharif University of Technology Kazemi, Fatemeh (Author) ; Borghei, Mahmoud (Supervisor)
    In this study, the effect of submerged vanes on the bed scouring and deposition pattern at a 90̊ open-channel junction was investigated. First, the bed formation without submerged vanes were studied under the effect of hydraulic variables like the discharge ratio of tributary to main channel and the ratio of mean approach velocity to the threshold velocity. The results show that scour holes enlarge with time while they move towards the downstream and the outer wall in the main channel. Also, by increasing the ratio of mean approach velocity to the threshold velocity about 0.5, the maximum scour depth occurred at the downstream junction corner with time. In the second stage, the proper vane... 

    Experimental Study on Erosion Control at Channel Junctions with Submerged Vanes

    , M.Sc. Thesis Sharif University of Technology Nozari, Soheil (Author) ; Jamali, Mirmosaddegh (Supervisor)
    In this study, the effect of submerged vanes on the bed erosion pattern at a 90° open-channel junction has been evaluated experimentally. In this study, 41 tests have been conducted in four different steps. In each test, the bed surface level has been measured at the end of 1st, 2nd and 24th hour. In the first step, the preliminary tests have been conducted. In this step, six different formations of submerged vanes have been selected and their performance has been evaluated and the most efficient formation, in the field of maximum scour depth reduction, has been selected. In the second step, six different formations of submerged vanes have been selected and their performance has been... 

    Hydraulic and Sediment Simulation of effect of structures On Urban Rivers In HEC-RAS (Case study :Kan River)

    , M.Sc. Thesis Sharif University of Technology Abhari Rasht Abadi, Maryam (Author) ; Agha Mohammad Hossein Tajrishi, Massoud (Supervisor) ; Torabi, Oveis ($item.subfieldsMap.e)
    Construction of some structures including parks, bridges and leading walls conducted on the rivers in urbanization leads to the change in the form of the rivers and consequently the change in the hydraulic.The response of river to these changes which are in the form of changes in morphologic features seems to pose some threats such as flood, damage to the buildings located on the route, weakening the bridge of highways and aggradation and degradation of the ecosystem. Kan river, one of the biggest urban rivers in the mega city of tehran, has had some changes such as resort purposes, canalization, the change of slip and roughness and intersection with different bridges during recent... 

    Hydraulic and Sediment Simulation of Rivers Passing Throw the City Affected by Land-Use Changes and Expansion of Human Activities (Case Study-Kan River’s Basin)

    , M.Sc. Thesis Sharif University of Technology Haghparast, Nazanin (Author) ; Tajrishi, Massoud (Supervisor) ; Torabi, Oveis ($item.subfieldsMap.e)
    understanding basin’s sediment transportation forms and river’s bed erosion in next years in addition to rivers’ response to watershed upstream activities, gives useful information to relevant experts for fundamental studies on expanding of development projects in neighborhood of kan River. This project is an effort to assess the amount of sediment production of Kan River’s basin using SWAT, modeling calibration by using measured data with SWAT-CUP and also prediction of river’s response to watershed activities in modeling river’s sediment in next years by using HEC-RAS. Several management approaches in different scenarios has been studied in order to control the sediment production and... 

    In-service corrosion evaluation in pipelines using gamma radiography - A numerical approach

    , Article Insight: Non-Destructive Testing and Condition Monitoring ; Volume 46, Issue 7 , 2004 , Pages 396-398 ; 13542575 (ISSN) Edalati, K ; Rastkhah, N ; Kermani, A ; Seidi, M ; Movafeghi, A ; Sharif University of Technology
    Wall thickness measurement and deterioration determination of 6 and 10 inch pipes due to corrosion/erosion/pitting was evaluated by using radiographic film density measurements. Special reference blocks were prepared with defined step wall reductions and artificial defects. Gamma radiography with a Ir-192 source was used. A double-wall technique with longitudinal film arrangement was used for this purpose. Formulae were developed from the experiments for numerical calculations. It was observed that this method can determine remaining wall thickness as well as pitting corrosion in insulated and non-insulated pipes with differential and absolute density measurements. The purpose of the work... 

    Application of the WEPP model to determine sources of run-off and sediment in a forested watershed

    , Article Hydrological Processes ; Volume 29, Issue 4 , 2015 , Pages 481-497 ; 08856087 (ISSN) Saghafian, B ; Meghdadi, A. R ; Sima, S ; Sharif University of Technology
    John Wiley and Sons Ltd  2015
    This study investigates critical run-off and sediment production sources in a forested Kasilian watershed located in northern Iran. The Water Erosion Prediction Project (WEPP) watershed model was set up to simulate the run-off and sediment yields. WEPP was calibrated and validated against measured rainfall-run-off-sediment data. Results showed that simulated run-off and sediment yields of the watershed were in agreement with the measured data for the calibration and validation periods. While low and medium values of run-off and sediment yields were adequately simulated by the WEPP model, high run-off and sediment yield values were underestimated. Performance of the model was evaluated as... 

    Prediction of erosive wear locations in centrifugal compressor using CFD simulation and comparison with experimental model

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 41, Issue 2 , 2019 ; 16785878 (ISSN) Biglarian, M ; MomeniLarimi, M ; Ganji, B ; Ranjbar, A ; Sharif University of Technology
    Springer Verlag  2019
    Erosive wear is one of the efficiency reduction causes in centrifugal compressors. The presence of suspended solid particles in the fluid causes deformations in different parts of the compressor, especially blades of the impeller. Therefore, erosion not only decreases the part lifetime by destruction of blades form, but also increases energy losses. For this reason, specifying the erosion locations and choosing a suitable material have an important effect on optimum functionality of the machine. In this paper, erosion locations of a compressor impeller by using computational fluid dynamics (CFD) in high temperature and pressure are attained and compared with experimental model. The... 

    Particle trajectory study in submerged flows with baffles using v 2̄ - f and k -ε turbulence models

    , Article 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, 7 January 2008 through 10 January 2008 ; 2008 ; 9781563479373 (ISBN) Mehdizadeh Momen, A ; Sherif, A ; Firoozabadi, B ; Sharif University of Technology
    In this paper, the structure of a wall jet deflected by a baffle along with the trajectory of particles has been studied. This baffle is used to produce a stable deflected surface jet, thereby deflecting the high-velocity supercritical stream away from the bed to the surface. An elliptic relaxation turbulence model (v2̄ - f model) has been used to simulate this submerged flow. During the last few years, the v2̄ - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proven that the v2̄ - f model is superior to other RANS methods in many fluid flows where complex flow features are... 

    New insight into hydrodynamic and cake erosion mechanism during rotating-disk dynamic microfiltration of concentrated bentonite suspensions at different salinity conditions

    , Article Separation and Purification Technology ; Volume 300 , 2022 ; 13835866 (ISSN) Movahedi, H ; Jamshidi, S ; Sharif University of Technology
    Elsevier B.V  2022
    The present study investigates the dynamic filtration of concentrated slurry fluids containing colloidal clay particles under different salinity, shear flow, and flux rate conditions. The dynamic filtration study was carried out by the filtration cell equipped with a rotating disk to apply shear stress over the membrane surface. A 3D CFD simulation has been implemented to model the hydrodynamic flows inside the filtration cell to obtain the wall shear stress (WSS) on the membrane surface at different disk rotation speeds. The thickness and surface patterns of fouling were captured utilizing a surface profilometer. First, the cake-filtration model was used to predict the flux rate and fouling... 

    Flexural Response Prediction of Concrete Beams Pre-Stressed with FRP Bars

    , M.Sc. Thesis Sharif University of Technology Momeni, Sajad (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    Fiber Reinforced Polymer (FRP) tendons are suitable to be used in concrete beams exposed to aggressive environments. This study proceeds the design and it presents the flexural capacity (in relation to the moment-curvature) for composite sections (reinforced with steel bars and pre-stressed FRP) rectangular, T-section which has been bent and broken. The failure is in attending with strain softening, stress hardening of fiber reinforced concrete (FRC) and reinforcing with steel bars and polymer. Using the predicted moment-curvature relationship, a numerical method is used to estimate the load deflection response at sample beams under concentrated and uniform loads. A parametric study will be... 

    Effects of tungsten on erosion-corrosion behavior of high chromium white cast iron

    , Article Materials Science and Engineering A ; Volume 454-455 , 2007 , Pages 623-628 ; 09215093 (ISSN) Mousavi Anijdan, S. H ; Bahrami, A ; Varahram, N ; Davami, P ; Sharif University of Technology
    In this study, effects of tungsten on wear resistance of high chromium white cast iron with and without tungsten in erosion-corrosion condition have been investigated. At the same time, the comparison between wear resistance of this grade of cast iron and low alloy steels with various contents of Cr which are used in industrial condition (in Sarcheshme Company, the greatest copper production company in the Middle East and with more than 4000 years historical cupper production background) was studied, while, copper concentrates have used for erosion particles. Results show that, because of higher hardness of matrix due to the tungsten, the wear resistance of high chromium cast iron increases.... 

    Numerical simulation of submerged flows with baffles uSING ν2̄ - F and k-ε turbulence models

    , Article 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006, Chicago, IL, 5 November 2006 through 10 November 2006 ; 2006 ; 08888116 (ISSN); 0791837904 (ISBN); 9780791837900 (ISBN) Mehdizadeh, A ; Firoozabadi, B ; Sherif, S. A ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2006
    This paper introduces the concept of a submerged hydraulic jump being used for energy dissipation. A baffle wall is used to produce a stable deflected surface jet, thereby deflecting the high-velocity supercritical stream away from the bed to the surface. An elliptic relaxation turbulence model (v 2̄ - f model) has been used to simulate this submerged flow. During the last few years, the v2̄ - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proved that the v̄2 - f model is superior to other RANS methods in many fluid flows where complex flow features are present. In this study,... 

    SRM performance improvement: Erosive burning phenomenon

    , Article AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, Sacramento, CA, 9 July 2006 through 12 July 2006 ; Volume 10 , 2006 , Pages 7649-7653 ; 1563478188 (ISBN); 9781563478185 (ISBN) Tahsini, A. M ; Sharif University of Technology
    American Institute of Aeronautics and Astronautics Inc  2006
    In this paper, the internal ballistics of solid propellant rocket motor with an arbitrary grain configuration is numerically investigated using quasi one dimensional simulation of Inviscid conservation equations. The upwind Roe's scheme is used to calculate the convective fluxes. Appropriate burning rate model to predict the erosive burning in solid propellant is used here. By using this phenomenon and accurate simulation, tactical motor performance can be considerably improved  

    Effect of nanoparticle behaviour on mud cake buildup for directional and horizontal wells: mathematical modelling and experimental study

    , Article Journal of Experimental Nanoscience ; Volume 11, Issue 12 , 2016 , Pages 975-999 ; 17458080 (ISSN) Sedaghatzadeh, M ; Ghazanfari, M. H ; Shahbazi, K ; Zargar, G ; Sharif University of Technology
    Taylor and Francis Ltd 
    The present study examined the effect of nanoparticle size and geometry on filter cake buildup during dynamic filtration using experimental and modeling approaches. A dynamic filtration setup was proposed and designed to test cross-flow circulation against a synthetic core at a constant differential pressure. The proposed mathematical model considers the critical deposition boundary of the porous media for particles along with drag, lift, friction, buoyancy, permeate, and electrostatic forces. The comprehensive model response allowed investigation of the aggregation and shape of nanoparticles at different cross-flow inclinations. The drag and lift force coefficients and moment of inertia of... 

    Prediction of Sand Production in Extraction Wells Using Numerical Simulation Based on Finite Element Method

    , M.Sc. Thesis Sharif University of Technology Fetrati, Majid (Author) ; Pak, Ali (Supervisor)
    Sand production is a phenomenon of producing solid particles together with the reservoir fluid. Material degradation is a key process leading to sanding. Drilling operation, cyclic effects of shut-in and start-up, operational conditions and reservoir pressure depletion may gradually lead to sandstone degradation around perforations and boreholes. Sand production is a major issue and has an adverse impact on production cost that gas and petroleum industry have faced for decades. Corrosion of the pipelines and surface facilities, sand-oil separation cost, repeated shut-in and clean-up of the wellbore are some of the examples. On the other hand, a controlled sanding could be beneficial in... 

    Numerical Modeling of Formation Damage Due to Filtrate Invasion into the Formation During Drilling Operations in Vertical and Horizontal Wells

    , M.Sc. Thesis Sharif University of Technology Khalili, Sajad (Author) ; Ghazanfari, Mohammad Hossein (Supervisor)
    Formation damage in oil and gas wells is mainly induced by drilling operations. Filtrate and particle invasion into formation as the sources of this damage caused serious problems, e.g. reduction of production rates. Therefore numerical modeling of this phenomenon helps us to better understand the process, and as a result, control and reduce formation damage associated with this impairment. In this research, a model to estimate the invasion depth and damage of mud filtrate from water-based mud is presented. Filtrate invasion into the formation is investigated by convection-diffusion equation with regard to dispersion term. The invasion depth is obtained from mud filtrate profile in the... 

    Piping Dam Breach Physical and Numerical Modelling Evaluation

    , M.Sc. Thesis Sharif University of Technology Seyed Raoufi, Arian (Author) ; Jafarzadeh, Fardin (Supervisor)
    In past few centuries , dams have been always a crucial part of human life . Using dams for agriculture and supplying water for people , has made them a valuable asset for countries . So evaluating dam safety and dam breach properties is so important. This issue is a geotechnical , structural and hydrological matter. Safety of earth dams could be threatened due to dam body breach caused by overtopping or pipping, during heavy floods, strong ground motions or any structural damage or defection. As in previous studies , calculating the final geometrical breach properties and time of failure was the main goal , we tried to connect this characteristics and find the relation of time and breach... 

    Using the laser irradiation to improve the rate of production of Iran South West formation

    , Article Society of Petroleum Engineers - Kuwait International Petroleum Conference and Exhibition 2012, KIPCE 2012: People and Innovative Technologies to Unleash Challenging Hydrocarbon Resources ; Volume 1 , 2012 , Pages 141-147 ; 9781622769766 (ISBN) Bazargan, M ; Habibpour, M ; Jalalyfar, H ; Geranmayehrad, A ; Sharif University of Technology
    Whole level of the erosion and the resistance of rocks which were composed closured have been studied, besides, the impact of temperature and laser irradiation for more investigation about this issue has been involved before all. This subject more reveals the matter which laser absorption on the laboratory scale using laser to what extent can cause the augment of the relative permeability and secondary porosity of reservoir rock, that of the vertical and horizontal useful connectivity and eventually that of the positive transferability. This research has been carried out in the form of case study on one of Iranian south west formations in north east of Behbahan city in Iran, either the rate... 

    Numerical simulation of sanding using a coupled hydro-mechanical sand erosion model

    , Article Journal of Rock Mechanics and Geotechnical Engineering ; Volume 12, Issue 4 , 2020 , Pages 811-820 Fetrati, M ; Pak, A ; Sharif University of Technology
    Chinese Academy of Sciences  2020
    Mechanical failure of materials adjacent to the production cavity and material disaggregation caused by fluid drag are considered as the most important parameters that affect sand production. In light of such factors, the coupling of two mechanisms-mechanical instability and hydrodynamic erosion-is indispensable in order to model this phenomenon successfully. This paper examines the applicability of a coupled hydro-mechanical erosion criterion for simulating sand production using the finite element method. The porous medium was considered fully saturated. The onset of sanding and production of sand were predicted by coupling mechanical failure and subsequent erosion of the grain particles...