Loading...
Search for:
newtonian
0.01 seconds
Total 130 records
Parallel Simulation of Generalized Newtonian Flows Using Smoothed Particle Hydrodynamics
, M.Sc. Thesis Sharif University of Technology ; Taghizade Manzari, Mehrdad (Supervisor)
Abstract
Smoothed Particle Hydrodynamics(SPH) is the oldest Lagrangian method for solving fluid equations. Fluid is approximated with particles that represent a control mass and carry physical properties su as mass, temprature and . . . Simpler formulation relative to other methods like finite volume and finite element, no need for surface traing and ease of adding new physics are benefits of this method. In this method it is necessary to find neighboring particles that are closer than smoothing lenght (h) for ea particle. is is a time consuming operation causing SPH to be a computationaly expensive method. First simulation of Power-law fluids is considered. It has been observed that using of...
Simulation of Competitive Flow in the Coronary Arteries Bypass
,
M.Sc. Thesis
Sharif University of Technology
;
Firoozabadi, Bahar
(Supervisor)
Abstract
Atherosclerosis is one of the most important factors for mortality and morbidity in the world. Coronary artery bypass graft (CABG) is applied for treatment of this disease which in this surgery, the patient vessels, such as internal thoracic artery and saphenous vein, are harvested and grafted to the coronary arteries. The graft success and its performance in short and long-term are depended on the much factors e.g. the severity of stenosis in the coronary artery. It should be noted that the low level of stenosis in the coronary artery causes the creation of undesirable phenomenon of competitive flow in the grafts after the surgery which this phenomenon has been reported as a cause of graft...
The Study of the Effect of Surfactant on the Liquid Drop Motion In Fluid
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Co-Supervisor)
Abstract
The drop motion in fluid and the mass transfer is one of the most interesting and favorite topics that has attracted the attention of many researchers. Knowing the functions of the factors affecting the deformation and the process of mass transfer and the effects of the addition of the surfactant, improve the efficiency of the related industrial processes.In this regard, the present study examines how the shape and speed of a moving Newtonian drop in a Newtonian fluid, the mass transfer of soluble material from inside the drop to the surrounding fluid and also the study of the effect of surfactant on the dynamics of moving droplet is studied numerically. During the drop movement, the...
Drag Reduction Using Geometrically Structured Surfaces for Non-newtonian Multi-phase Fluids
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
With the advancement of the industry, microscale devices use due to its unique characteristics. On the other hand, it is essential to find ways to reduce drag inside microchannels because of The importance of energy. One of the methods is to optimize the contact surface using structured geometric surfaces. These hydrophobic surfaces reduce drag by trapping the air in roughness and creating a two-phase flow. The purpose of this project is to reduce the drag within the microchannel using structured geometric surfaces for non-Newtonian and multiphase flows. In most previous studies, with simplification, Newtonian and two-phase flows have been investigated. While most industrial fluids show...
Observational Tests of MOdified Gravity (MOG)and Non-Local Gravity with Galaxies’ Dynamic
, Ph.D. Dissertation Sharif University of Technology ; Rahvar, Sohrab (Supervisor) ; Moffat, John (Co-Advisor)
Abstract
Dark matter is one of the biggest unsolved problems in physics and cosmology. Almost 85 percent of the gravitational matter is not luminous and it’s properties is unknown. In recent decades variety of investigations regarding dark matter has been done which we will mention in the beginning part of this thesis. We continue testing MOdified gravity (MOG), Non-Local-Gravity (NLG) and MOdified Newtonian Dynamics (MOND) in a different scale by using the rotation curves of dwarf galaxies. In addition we compare MOG, MOND and NLG together to see which one better fit observed data. In another investigation that is reported in this thesis, we fit the observed acceleration data of galaxy cluster Abell...
Numerical Investigation on Oil/Water Separation through Coalescence in Membrane Pores
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
Oil/water separation is an important field, not only for scientific research, but also for environmental, economic, and social issues. On the one hand, oily wastewater, resulting from industries such as steel, aluminum, food, textile, leather, petrochemical and metal finishing, has become the most common pollutant all over the world. On the other hand, frequent oil spill accidents are of great concern since the discharge can lead not only to serious environmental pollution, but also a great loss of energy.
In crude oil removing water is necessary due to reducing corrosion, increasing thermal values of fuels obtained from crude oil, preventing catalists from destruction by water and...
In crude oil removing water is necessary due to reducing corrosion, increasing thermal values of fuels obtained from crude oil, preventing catalists from destruction by water and...
Experimental and Theoretical Investigation of Ascending Accelerated Motion of Single Bubble in Quiescent Newtonian and Non-newtonian Liquids
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Supervisor)
Abstract
The gas-liquid interaction is one of the most important and common phenomenons in chemical, biochemical and mineral industries which is generally observed as liquid in a gas stream (droplet) or gas in a liquid stream (bubble). Although bubbles produced in the industrial applications are in the form of a group of bubbles, understanding the hydrodynamics of a single bubble in a quiescent liquid provides a starting point for studying bubble groups. It should be noted that changes in the velocity and drag coefficient of the bubbles in various fluids are essential parameters for designing gas-liquid systems. In the present research, in order to examine the effect of system parameters and...
Simulation of Non-newtonian Flow of Drilling Fluid Around the Drill String with the Olga Software
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
Because of the importance of simulations in the oil industry, there are different software applications designed for this purpose. The purpose of the simulation in the oil industry is to reduce operational errors during the operation and to achieve the most ideal mode of operation. However, in the simulation of multiphase fluid flow because of the special circumstance, simulation plays an important role in the oil industry. OLGA multiphase flow simulation software is a strong simulation software for water, oil, Gas wells, wellhead facilities, refineries and pipelines and it is capable of simulating pipelines under various dynamic conditions. Simulation of drilling hydraulic parameters is...
Numerical Simulation of Heat Transfer on Topographically Structured Surfaces
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
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...
Experimental Study of a Single Bubble Formation and Its Deformation in Shear-thinning Fluids
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Firoozabadi, Bahar (Supervisor)
Abstract
Bubble formation and bubble rising are widely used in many industrial processes such as bubble columns, extraction, fermentation, foaming and polymerization. Although many of these processes are faced with a series of bubbles, this study may help us better understand the hydrodynamics of single bubble formation and bubble rising and provides a deep insight into the modeling of a series of bubbles. Bubble velocity and drag coefficient in various fluids are the major parameters for designing the liquid-gas systems. These parameters are a function of the bubble size. In this study, single bubble formation is theoretically modelled in order to predict the size of the bubble at the moment of...
Simulation of Blood Flow in Deformable Arteries using SPH
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
Since coronary artery diseases are increasing every day, simulation of blood flow in blood vessels and their stenosis is one of the most important topics nowadays. Many efforts have been made to achieve numerical simulations using different methods such as Finite-Difference. In this thesis, an SPH method is used to simulate pulsatile blood flow in arteries. The weakly compressible algorithm consists of two steps of prediction and correction. In the prediction step, the velocity field is integrated forward in time without enforcing incompressibility. The correction step consists of enforcing incompressibility by solving the pressure Poisson equation which creates a trade-off between the...
Numerical Fluid–Structure Interaction and non-Newtonian Simulation of Blood Flow in a Compliant Carotid Bifurcation
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Saidi, Mohammad Saeid (Co-Advisor)
Abstract
Researchers have done a lot of studies about the use of CFS in blood flow modeling in order to improve the supplementary devices or find mechanical factors which cause artery to be diseased. Blood is a complex rheological fluid, blood flow is a pulastile flow, and blood flow field interacts with the deformable vessel wall. Thus, blood flow modeling like other biological phenomena has its own complexities such as anisotropy, vsicoelasticity, and nonlinearity in stress-strain relationship of vessel wall. To explore the role of hemodynamics in the initiation and progression of stenosis in carotid artery bifurcation, a 3D Computational Fluid Dynamics (CFD) technique is applied. The effect of...
Simulating Structure Formation in Modified Newtonian Dynamics
, M.Sc. Thesis Sharif University of Technology ; Rahvar, Sohrab (Supervisor)
Abstract
We simulated the structure formation in the context of Modified Newtonian Dynamics with the spherical collapse model. We supposed a spherical region with mass of galactic order, positive density contrast and uniform distribution of matter as the initial condition and investigated the evolution of its internal regions, containing different amounts of matter. We began the simulation when the region was in Newtonian regime. The overdense region, which expands with cosmic fluid in Newtonian regime, gradually enters MONDian regime and gets separated from the background due to its stronger central acceleration; then it collapses and virializes after some swings. The density distribution of the...
Experimental Investigation on the Accelerated Motion of Newtonian and Non-Newtonian Liquid Drops
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Supervisor)
Abstract
Motion of liquid drops into another fluid is of central importance in a variety of most commonly used industries. Vast applications of emulsions in food and drug industries as well as using of drops in liquid-liquid extraction processes and direct contact heat exchangers are examples in which dynamics of motion of drops play a significant role in operation and efficiency.
In present study, we consider the accelerated motion of Newtonian and non-Newtonian liquid drops experimentally. In order to find the effect of bulk fluid on the motion of drops, air and water are used as bulk fluid. The experiments have been done on Water, Ethanol, Ethyl acetate, n-Hexane and Toluene as Newtonian and...
In present study, we consider the accelerated motion of Newtonian and non-Newtonian liquid drops experimentally. In order to find the effect of bulk fluid on the motion of drops, air and water are used as bulk fluid. The experiments have been done on Water, Ethanol, Ethyl acetate, n-Hexane and Toluene as Newtonian and...
Numerical Investigation of Instabilities of Flow in Micro-fluid
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
This research concerns investigating the behavior of two-phase flow in the inlet and outlet of the microchannels.Both the droplet based and the continuous microfluidics are considered. For the continuous system whenthe minor fluid enters the microchannel, due to ratio of viscosity of two fluids, viscous folding occurs.Viscous folding phenomena is similar to the buckling phenomena in solids.This means that the viscosity of the fluid, which is applied to two sides of the fluid layer, causes folding the fluid layer and changing the shape of it. For the study we employ a VOF based numerical routine. In order to verify numerical results, the grid and the time step independenciesare checked. In...
Simulation of Blood Flow Subjected to Magnetic Field
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor) ; Shafie, Mohammad Behshad (Supervisor)
Abstract
Considering the fact that there is a blood flow inside the vessels it is possible that blood flow is always associated with fouling and this may decrease the blood flow when a blood vessel is injured, the cells of your blood bond together to form a blood clot. The blood clot helps you stop bleeding. Blood clots are made of a combination of blood cells, platelets (small sticky cells that speed up the clot-making process), and fibrin (protein that forms a thread-like mesh to trap cells). Doctors call this kind of blood clot a “thrombus.” We study the effects of different parameters on the deposition of Nanoparticles on the surface of a bump in the blood vessels by the magnetic field. The...
Study on Viscoelastic Fluid Flow in Channels with Dead End and Valuation in Micro Model
, Ph.D. Dissertation Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor)
Abstract
It is about half century passed from the invention and application of the polymer flooding. Although there are successful reports from the using polymer flooding, but there are problems that in some cases this process fails. For more insight on the problems and in order to improve
the efficiency of this process the conceptual understanding of the process is required. More conceptual understanding from this process, requires investigation in pore scale. In the presenting investigation, the flow of Newtonian and non-Newtonian fluids in the single phase and two phase form and in pore scale are simulated using finite volume method. Because, the finite volume method is used in very...
the efficiency of this process the conceptual understanding of the process is required. More conceptual understanding from this process, requires investigation in pore scale. In the presenting investigation, the flow of Newtonian and non-Newtonian fluids in the single phase and two phase form and in pore scale are simulated using finite volume method. Because, the finite volume method is used in very...
Molecular Dynamics Simulation of Electroosmotic Flow in Nano scales
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud (Supervisor)
Abstract
Due to important applications and benefits of mass transfer in engineering and especially in nano-scales engineering, nano-science researchers have focused on this field. Considerably, in classical fluid dynamics applications, the fluid can be transported using differential pressure gradient. But the classical methods require moving components, which are usually expensive and not applicable in nano-sizes. To avoid these problems in nano-size transportation, we can use electro-osmotic process to perform mass transfer in low transfer rates. In electro-osmotic process, we can move electrolyte solvent with the aid of an external electrical field. Due to importance of this process in...
Fabrication of Superhydrophobic Surfaces to Decrease Pressure Drop through the Galvanized Pipe and Study about Feasibility of the Fabricated Surface to Use for Non-newtonian Fluid
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor) ; Nouri boroojerdi, Ali (Supervisor)
Abstract
Nowdays, one of the most important concerns for scientists is increasing CO2 emmisions and global warming. To overcome this problem, a large number of studies have been carried out to improve energy system performance and reducing the overall energy consumption. One solution to this problem is using the superhydrophobic surfaces with contact angle larger than 150°.In this study, we try to reduce the pressure drop through the galvanized pipes. So, by reducing the pressure drop, power required for pumps can be reduced. To this end, two different coatings by silica nano-particles which were modified with first hydrophobic agent are used. In first coating which is named as PS coating, stearic...
Experimental Study of Droplet Formation in Surfactant Solution
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Co-Advisor)
Abstract
Surfactants are materials that reduces surface tension, and this property has provided a wide range of applications for them. Most of the surfactants reduce surface tensions at the interface of two fluids. The pharmaceutical and food industries, detergents, cosmetics, agricultural pesticides, dye production and oil extraction are among these applications.In this study, the formation of droplets in the presence of three types of surfactants SDS, CTAB and Tween 20 has been investigated. To evaluate the droplet behavior in the presence of specific surfactants, various parameters such as formation time of the droplet, the diameter and length of the droplet formed, the diameter and length of the...