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hydrodynamics
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Experimental Study on Hydrodynamic Behavior of Drilling Fluid by Fluidizing Granular Materials in an Annulus
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor) ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
During the drilling process, cutting concentration in vertical and inclined wells is a common problem and major issue in designing hydraulic parameters. This is becoming more important in near bit area. Cutting transport usually is affected by several parameters such as mud rheology, flow rate, nozzle size, rotation speed, and mud weight.
In this work it was aimed to design a new set-up to test all the factors on hole cleaning phenomenon especially in near bit area. The set-up consists of a 16 feet long flow loop, 3.28 feet height of the test section, and 3.33 inches inner diameter of the test section. Each parameter which has an impact on hole cleaning could be varied. The cutting...
In this work it was aimed to design a new set-up to test all the factors on hole cleaning phenomenon especially in near bit area. The set-up consists of a 16 feet long flow loop, 3.28 feet height of the test section, and 3.33 inches inner diameter of the test section. Each parameter which has an impact on hole cleaning could be varied. The cutting...
Investigation of Hydrodynamic Interaction between a Squat Submarine Operated behind a Ship
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour, Madjid (Supervisor) ; Mohtasham Dolatsahhi, Kiarash (Supervisor) ; Sani, Mahdi (Co-Supervisor)
Abstract
This research investigates the hydrodynamic interaction of a squat submarine operating behind a ship in various wave and resistance experiments for towing and self-propelling arrangements. A one-tenth scaled captive model of a 0.625 m squat submarine is constructed along with a 1.5 m Fridsma ship to perform 116 unique experiments in a 4×6×400 m3 tank located in a towing tank center. The submarine is a new midget-submersible, of Apam-Napat SMSD type, with an L/D ratio below four. The cable is specified, regarding its weight per unit length, using a scaling method introduced in this research. Wave and resistance tests are performed for various 2D relative lengths and depths at short-distance...
Hydrodynamic Performance of Squat Submarine Equipped with Passive Pressure Drag Reductions
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour, Madjid (Supervisor) ; Mohtasham Dolatshahi, Kiarash (Supervisor) ; Sani, Mahdi (Co-Supervisor)
Abstract
This research empirically examines the hydrodynamic performances of squat submarines under the resistance and wave tests, besides the numerical investigation of pressure drag reduction techniques. Submarines are limited for public use due to military classification issues and being expensive. This research introduces a new squat submarine in order to enable underwater exploration. This squat submarine has a 9- person capacity as a manned midget submersible using specific geometries of length-over-depth ratios (L/D) below four. The cause of such selection is to provide better visibility for the passengers to research and explore the sea. However, the geometrical features considerably change...
Numerical Study of Heat Transfer Enhancement in Porous Medium by Applying Magnetic Field on Nano Fluid
, M.Sc. Thesis Sharif University of Technology ; Sadrhosseini, Hani (Supervisor)
Abstract
A 2D simulation has been carried out to study the effect of magnetic field on heat transfer and pressure drop of nanofluid flowing through a pipe filled with porous medium. The nanofluid flow is modeled as a single-phase flow, and Darcy–Brinkman–Forchheimer equation is employed to model fluid flow in porous media. A constant uniform heat flux was imposed on the walls of the cylinder, and the values of Darcy number, Hartmann number, and volume fraction of the nanoparticles were selected as 0.1, 200, and 0.2, respectively. Effects of parameters such as Reynolds number, the material of the porous medium (conductivity and porosity), and material of nanofluids have been investigated in the...
Simulation of Droplet Sorting in Microfluidic Systems
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor) ; Asghari, Mohsen (Supervisor)
Abstract
A new microfluidic device is introduced for sorting the particles based on the hydrodynamic resistance induced in a microchannel which is not needed for additional detection or sorting modules. Hydrodynamic resistance affects physical properties, such as size and deformability of the particle. This device could apply application in cell sorting for remedies, diagnostics, and industrial applications. The device design is performed using an equivalent resistance model, and also numerical simulations are performed. For validation of the results, they are compared with experimental results. Moreover, we will discuss threshold particle size and will introduce a way to approximate it to ...
Experimental Study of Molybdenum Extraction Process in an Oldshue-rushton Extraction Column
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Torab- Mostaedi, Mesam (Supervisor) ; Asadollahzadeh, Mehdi (Co-Supervisor)
Abstract
Extraction and separetion of molybdenum is important because of its application in different industries. Since molybdenum resources are finite and low-grade, hydrometallurgical methods can be used to extract molybdenum. Solvent extraction of rare metals one of the important processes of hydrometallurgy.In the first of research, molybdenum solvent extraction from sulfate msoloution was investigated in batch and semi-industrial scale. In the laboratory scale, molybdenum solvent extraction from aqueous solution was investigated by using of D2EHPA, Cyanex272 and TBP. The effects of various parameters such as extractrant concentration, synergistic enhancement factor for mixture of extractants,...
Hydrodynamic Circuit Modeling of Surge Control System of a Centrifugal Compressor with Variable Gas Combination to Combine an Active Surge Control System with Surge Avoidance System
, M.Sc. Thesis Sharif University of Technology ; Mazaheri, Karim (Supervisor)
Abstract
In this research, first, the performance map and surge line of 46M6 and 46MB8 multi-stage radial compressors, which have 6 and 8 stages, respectively, have been estimated and invarianted. Invarianting the performance map makes the performance curve and surge line of the compressor, unchanged from input conditions, including molecular weight, which is very important for control systems. Then, the hydrodynamic circuit of Compressor System C-3002 of Nouri Petrochemical Company was modeled according to the characteristics of its components by solving equations in MATLAB software. main working condition of the hydrodynamic circuit is close to Start of Life operating condition which has a...
Numerical Simulation of Natural Convection Using Smoothed Particle Hydrodynamics with Artificial Compressibility Method
, M.Sc. Thesis Sharif University of Technology ; Hejranfar, Kazem (Supervisor)
Abstract
In this research, the numerical simulation of the natural convection is performed by using the smoothed particle hydrodynamics based on the artificial compressibility method. For this aim, the formulation of the artificial compressibility method in the Eulerian reference frame for the mass and momentum equations is written in the Lagragian reference frame and the Lagrangin form of the energy equation is also considered to compute the thermal effects. The benefit of the artificial compressibility-based incompressible SPH (ACISPH) method over the weakly compressible SPH (WCSPH) method for computing the natural convection is that there is no need in the formulation considered here to use any...
Thermal and Hydrodynamic Analyses of Shell and Tube Heat Exchangers in Different Flow Regimes Using Semi-Full-Scale Simulation Approaches
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud (Supervisor)
Abstract
One main problem in many numerical simulations is the lack of sufficient infrastructure data to precisely model and analyze the flow through complex geometries. Since experimental procedures are generally very expensive; and sometimes impossible, it becomes necessary to find alternative ways such as numerical approaches to predict the flow behavior through complex geometries. The heat exchangers can be categorized as geometries with complex configuration and apparently expensive to solve numerically. They are widely used in different industries including the aerospace. The restrictions in design and implementation of aviation’s heat exchangers have promoted the related companies to converge...
Numerical Simulation of Incompressible Turbulent Flow with the Artificial Compressibility-Based Incompressible Smoothed Particle Hydrodynamics
, M.Sc. Thesis Sharif University of Technology ; Hejranfar, Kazem (Supervisor)
Abstract
In the present study, an incompressible smoothed particle hydrodynamics based on the artificial compressibility method is applied for simulating the incompressible turbulent flows. The Reynolds-averaged incompressible Navier–Stokes equations using the artificial compressibility method in the Eulerian reference frame are written in the Lagrangian reference frame to provide an appropriate incompressible SPH algorithm for the turbulent flow computations. Here, the k-L_m turbulence model, which is a simplified k-ϵ turbulence model, is used and formulated in the Lagrangian reference frame. The SPH formulation implemented here is based on an implicit dual-time stepping scheme to be capable of...
Development of an Incompressible Smoothed Particle Hydrodynamics Method based on Vorticity-stream Function Formulation
, M.Sc. Thesis Sharif University of Technology ; Hejranfar, Kazem (Supervisor)
Abstract
In the present study, an incompressible smoothed particle hydrodynamics method based on vorticity-stream function (VSF-SPH) formulation is developed and assessed for simulating steady and unsteady incompressible flows. The vorticity-stream function formulation in the Eulerian reference frame is written in a Lagrangian reference frame to provide an appropriate incompressible SPH algorithm. The advantage of the proposed smoothed particle hydrodynamics method based on the vorticity-stream function (VSF-SPH) formulation over the weakly compressible SPH (WCSPH) is that the VSF-SPH method is a truly incompressible SPH algorithm and it does not involve any approximate enforcement of the...
Prediction of Droplet size and Velocity Distribution by using Maximum Entropy Method
, M.Sc. Thesis Sharif University of Technology ; Kebriaee, Azadeh (Supervisor)Central Difference Finite Volume Lattice Boltzmann Method for Simulation of Incompressible Electro-Magneto-Hydrodanamic Flows
, M.Sc. Thesis Sharif University of Technology ; 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...
Computational Simulation of High Density Ratio Drop Deformation and Breakup, Using Lattice Boltzmann Method
, M.Sc. Thesis Sharif University of Technology ; Taeibi Rahni, Mohammad (Supervisor) ; Karbaschi, Mohsen (Supervisor)
Abstract
Deformation and breakup of drops are the basisof many interfacial flow studies and appear in a number of industrial applications, e.g., spray painting, spray combustion, emulsion, foam, sedimentation, and rain. Following their formation, drops may enter a region where hydrodynamicforces are large enough to cause their significant deformation and breakup. When a drop breaks apart into a multitude of small fragments due to disruptive hydrodynamicforces, the process is termed secondary atomization or breakup. Due to many engineering and scientific applications of multiphase and multi-component flows, they have been the main topic of many researchers for many years. Particularly, interfacial...
Two-Dimensional Computational Simulation of Fluid-Solid Interaction in Tearing of a Membrane between two liquids with Different Molecular Properties and Pressures, Using SPH Method
, M.Sc. Thesis Sharif University of Technology ; Taeibi Rahni, Mohammad (Supervisor) ; Javadi, Khodayar (Supervisor)
Abstract
Smoothed particle hydrodynamics (SPH) is a meshfree method, based on Lagrangian formulation of Navier-Stokes equations, in which fluid is discretized to particles. This method is suitable and gives much better results for problems in which other methods have severe difficulties, (e.g., tracking of particles, moving boundaries, and problems with large deformations and, physical discontinuity). No need to follow a regular geometric structure in solution process and simple adaptation and coupling with methods such as finite element, are the positive characteristics of this numerical method. In this work, a systematic study of the processes, which are part of a membrane failure in a...
The Study of Hydroelastic Behavior of Submerged Slender Bodies Considering Sloshing in Tanks
, M.Sc. Thesis Sharif University of Technology ; Haddadpour, Hassan (Supervisor)
Abstract
In the present work, dynamic behavior of submerged slender bodies under external hydrodynamic forces with internal sloshing tanks is studied. The main application of this thesis is in submarines. For this purpose slender body theory is used for hydrodyanamics of body and unsteady hydrodynamics is used for the vehicle control fins. In submarines there are some water tanks that control the buoyancy, so that sloshing can be importatnt. An equivalent mechanical model is developed for simulating the dynamics of sloshing tanks. Assuming that a submarine is a slender body, elastic deformation of submarine body can affect dynamics of the whole system. Elastic behavior of the main body is simulated...
Numerical Modeling of Liquid Jet Breakup Using SPH Method
, M.Sc. Thesis Sharif University of Technology ; Morad , Mohammad Reza (Supervisor) ; Omidvar, Pourya (Supervisor)
Abstract
Smoothed Particle Hydrodynamics (SPH) is a numerical Lagrangian meshless method which has numerous applications in astrophysics, hydrodynamics, free-surface flows, jets and sprays formation. Atomization of continuum liquid to fine droplets or in other words, liquid breakup processes are emerged in many engineering applications such as fuel sprays inside the combustion chamber of internal combustion engines that sizes of produced sprays significantly influence the engine’s efficiency. This research is accomplished to investigate the one-phase and two-phase flows of liquid jet breakup. For this aim, an open source code called SPHysics which solves the flow field by SPH method is utilized. This...
Development of a Three-Dimensional Numerical Hydrodynamic Model of Lake Urmia Using Satellite Data Integration, Field Data, and Data Assimilation
, M.Sc. Thesis Sharif University of Technology ; Safaie Nematabadi, Ammar (Supervisor)
Abstract
The aim of this research is to use data assimilation in hydrodynamic modeling of Lake Urmia, which is known as one of the world's hypersaline lakes. In other words, it is the first time that the development of a numerical model for Lake Urmia has been accompanied by data assimilation. In recent years, Lake Urmia has experienced unfavorable climatic conditions, resulting in a decline of over 8 meters in its water level over the past 20 years. Hydrodynamic analysis of the lake can play a crucial role in major management decisions for restoration of the lake ecosystem. In this project, the three-dimensional FVCOM model was used to perform numerical modeling, and efforts were made to improve...
Development of an Improved Wet/Drying Algorithm for Hydrodynamic Models to Ppredict Water Salinity in a Hypersaline Lake: the case of Lake Urmia
, M.Sc. Thesis Sharif University of Technology ; Safaie, Ammar (Supervisor)
Abstract
Considering the significant impact of salinity and temperature on the life of aquatic ecosystems, the growth of plants and animals, and the health of people; it is necessary to predict the spatiotemporal distribution of these qualitative characteristics in aquatic environments by using precise algorithms through hydrodynamic models. This research presents an improved algorithm for calculating qualitative characteristics of aquatic environments, such as salinity, during the wet/drying processes. The developed algorithm in this study has been incorporated into FVCOM which is a three-dimensional hydrodynamic model. The current algorithm governing the FVCOM model is not capable of accurately...
Development of a Hydrodynamic and Water Quality Model of Lake Urmia
, M.Sc. Thesis Sharif University of Technology ; Safaie, Ammar (Supervisor)
Abstract
Due to anthropogenic activities and climate change, Lake Urmia, one of the largest hypersaline lakes, is exposed to desiccating. The increase in salinity in this lake up to more than 400 p.s.u has endangered the ecology of this lake. In this study, a three-dimensional, unstructured grid and finite volume model FVCOM has been developed to investigate Lake Urmia's hydrodynamics, salinity, and water temperature over the year 2016. Some of the model inputs were lake bathymetry, meteorological data (including air temperature and pressure, wind speed and direction, short-wave and longwave radiation), precipitation, evaporation, river flux, salinity, and temperature. The model was calibrated...