Sharif Digital Repository

Highlights: The objective of this work is to investigate the effects of the surfactants on the oil extraction from the dead ends through the numerical simulations and experimental evidences. The volume of fluid approach in the frame of the finite volume method has been used for numerical simulations in 2-D domain and experimental flooding tests have been done using a glassy micro-model. The effects of the water-oil, water-wall and oil-wall interfacial tensions have been investigated numerically and some results are compared to experimental flooding results. Simulations have been done in the cases of water-wet, neutralized-wet and oil-wet micro-models also. The numerical results show that in... 

Smoothed particle hydrodynamics (SPH) was applied to simulate the free falling of cylindrical bodies in three types of fluids including Newtonian, generalized-Newtonian and viscoelastic fluids. Renormalized derivation schemes were used because of their consistency in combination with the latest version of no slip boundary condition to improve the handling of moving fluid-structure interactions (FSIs). Verification of the method was performed through comparing the results of some benchmark examples for both single and two phase flows with the literature. The effects of some parameters such as the viscosity of the Newtonian fluid, the n index of the power-law fluid and the relaxation time of... 

This research deals with the numerical simulation of two viscoelastic uids ow in an open capillary of a reservoir. Oldroyd-B and Leonov models have been used to describe the rheological behavior of polymer solutions. The finite volume method on a structured and collocated grid has been used for discretization of the governing equations. The discrete elastic viscous stress splitting technique has also been used. The steady state, isothermal and incompressible uids past through a two dimensional micropore have been considered. The numerical method has been validated through the comparison of numerical results by the analytical solutions of Oldroyd-B uid ow through a planar channel. The effects... 

This paper presents an offline path planning method in 3D space for a surveillance aerial vehicle. In this method, the aerial vehicle is supposed to visit particular points on the path, and the collision between the vehicle and the fixed obstacles in the environment must be avoided. In order to accomplish the mission, first, the path is generated using B-splines. Then, the feasibility of tracking the designed path for the vehicle is considered by analyzing the vehicle's dynamic constraints, such as limitations on deflections of control surfaces. The analysis is supported by a simulation. Potential extension of the proposed analysis to multiple aerial vehicles has been also discussed at the... 

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... 

In this paper, a fuzzy based controller is developed in order to control the braking action of the rear axle of a series hybrid city bus. The controller's target is to recapture the kinetic energy of the bus as much as possible during braking, while still maintaining its stability. The bus under study Is one of the Iran-Khodro Company's productions called O457 which is currently undergoing a procedure of hybridization. The hybrid type used is a series hybrid configuration in which an internal combustion engine and a battery pack supply Its electric traction motors in order to propel the bus. The implemented fuzzy controller takes the bus speed, batteries SOC level and the brake-pedal... 

Water and energy are the major factors in the new United Nations Sustainable Development Goals. Sustainable conversion and management in the secure supply of increasing demand for water and electricity is a challenging concern. It is recently complicated due to economic development, population growth, resource depletion, and climate change, which requires a simultaneous progressive planning. Since energy and water systems are instinctively interdependent and mutually interacted (known as nexus), this paper employed an integrated solution-based method. A bottom-up optimization model is developed considering Water-Energy-Emission Nexus approach for both power and water sectors. The model... 

In this study the extrudate swell of polymer solutions is estimated using the microstructure of polymer molecules. When a flexible polymer chain goes through a narrow die shear stress exerting on the chain will cause the polymer chain to be stretched along the flow direction. After emerging from die all external stresses vanish immediately and the chains tend to recover their previous state due to elastic recovery. This phenomenon will results in a gradual increase in extrudate diameter and this is used as the key idea for estimating swell ratio. A Giesekus based conformational model was used in order to predict polymer chains microstructure everywhere in the domain. The resulting PDE set... 

In this study, the flow of a fiber filled viscoelastic matrix through planar contractions is investigated. It was found that by adding fiber to the matrix vortex, the intensity increases. Fiber orientation along "x" and "y" axes was studied too. It was found that fiber orientation could be used for determining the flow regime through the contraction geometry. The rigidity condition of fibers, which needs the trace of the orientation tensor to be unity everywhere in the domain, is correct except near walls and the reentrant corner, which is slightly less than one. In these regions, the stress magnitude is higher, which results in more numerical errors, and which further leads to some error in... 

Tortuosity and cementation factor are two critical parameters that significantly affect estimates of reservoir properties. Tortuosity factor can be used to estimate permeability using the Carman-Kozeny equation and is an important parameter for formation resistivity factor calculation using a modified version of Archie's formula. It is also used to predict water saturation of reservoir rocks. Tortuosity as an input parameter in Biot's equation can be used to estimate velocity dispersion. In this work, based on the Generalized Archie Equation Curve Fitting (GAECF), tortuosity and cementation factor are determined for selected intervals in a carbonate reservoir. Formation resistivity factor... 

Hybridization of conventional vehicles is considered an important step to achieve high fuel economy and low emissions. In this study, principle considerations involved in a hybridizing process are discussed and consequently, a sequential approach for designing hybrid components for both series and parallel configurations has been introduced. The so called approach has then been applied to one of the productions of Iran-Khodro Company called SAMAND. Having designed the hybrid components, the conventional SAMAND and its series and parallel hybrid configurations were defined and evaluated using the ADvanced VehIcle SimulatOR (ADVISOR) software. It is observed that compared to the conventional... 

Contraction flow is one of important geometries in fluid flow both in Newtonian and non-Newtonian fluids. In this study, flow of a viscoelastic fluid through a planar 4:1 contraction with rounded corners was investigated. Six different rounding ratios (RR =0, 0.125, 0.25, 0.375, 0.438, 0.475, 0.488) was examined using the linear PTT constitutive equation at creeping flow and isothermal condition. Then the resulting PDE set including continuity, momentum, and PTT constitutive equations were implemented to the OpenFOAM software. The results clearly show vortex deterioration with increasing rounding diameter, so that when rounding corner exceeds a critical value, the vortex disappears... 

This paper presents an application of the analytical hierarchy process and fuzzy analytical hierarchy process methods for selecting the best wastewater treatment process. The analytical hierarchy process is one of the best ways for deciding among the complex criteria structure in different levels, and the fuzzy analytical hierarchy process is a synthetic extension of the classical method when the fuzziness of the decision makers are considered. After reviewing aerobic treatment processes operated in Iran's industrial estates and determining the main criteria used for treatment process evaluation, they are arranged in a hierarchy structure. Selection of the best wastewater treatment process... 

This paper presents an application of the analytical hierarchy process and fuzzy analytical hierarchy process methods for selecting the best wastewater treatment process. The analytical hierarchy process is one of the best ways for deciding among the complex criteria structure in different levels, and the fuzzy analytical hierarchy process is a synthetic extension of the classical method when the fuzziness of the decision makers are considered. After reviewing aerobic treatment processes operated in Iran's industrial estates and determining the main criteria used for treatment process evaluation, they are arranged in a hierarchy structure. Selection of the best wastewater treatment process...