Loading...
Search for:
hydraulics
0.015 seconds
Total 337 records
Experimental Study of Geotextile's Drainage and Filtration Properties in Dams under Different Hydraulic Gradients and Boundary Conditions
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
Geotextiles are one of the most widely used materials in filtration and drainage applications. Since geotextiles are exposed to different stresses and hydraulic gradients, thier hydraulic behavior in real situations is of great importance. In this study, filtration and drainage of several nonwoven needle-punched geotextiles with different properties and unit masses per area of 200g/m2, 400g/m2, 500g/m2 and 800g/m2 under various confined stresses and hydraulic gradients are investigated. To get to these aims, permittivity and transmissivity apparatuses were designed and built in the course of this investigation. Then samples which were emerged for at least 24 hours were tested under different...
Experimental Study on Sediment Non-uniformity Effects on Local Scour Due to Hydraulic Jump Using Buried Plates
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mahmood (Supervisor)
Abstract
Local scour downstream of sluice gates in the erosive bed is one of the main concerns of hydraulic engineers, since it can cause serious damage to the structure. One of the ways to overcome this problem is the use of apron, or non-erosive bed. In order to shorten the apron or decrease the effect of the turbulence flow, different measures can be used. These approaches can be divided into two main branches, "Energy dissipating" and "bed reinforcement" measures. This study has investigated the scour phenomenon under the different conditions of the bed material gradation and bed reinforcement using vertical buried plates. The effect of sediment non-uniformity, unlike uniform sediment, has a...
Study of the Effects of Geo-mechanical and Hydro-mechanical Parameters on Hydraulic Fracturing Characteristics in Oil Reservoirs by Numerical Modeling
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
Increasing the permeability of hydrocarbon reservoirs by creating artificial cracks that are induced by injection of fluids under high pressures is called Hydraulic Fracturing operation. This method is widely used in petroleum reservoir engineering. For design of Hydraulic Fracture operations, a number of methods have been developed. KGD and PKN are the first and most used methods in this area and despite the development of advanced softwares in recent years, these methods are still popular and are used in a number of softwares. KGD is commonly used for induced fractures where the height of fracture is greater than its length, and PKN is normally used where the length of the fracture is...
Numerical Evaluation of the Influence of Hydro-Mechanical Factors on the Conventional Methods of Hydraulic Fracture Analysis in Oil Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
The exploitation of oil and gas has been changed dramatically since the advent of hydraulic fracturing. Hydraulic fracture is one of the enhanced oil recovery methods in which high-pressure injecting fluid is pumped into the well to overcome the lowest in-situ stress and rock resistance to create cracks in the deep-rock formations. It is estimated that the benefits of the mentioned method lead to a net economic profit of $48 billion per year in the world’s oil and gas industry.While there are various analytical models for predicting hydraulic fracture characteristics, KGD and PKN are amongst the most popular Models. The conditions of plane strain in two-dimensional space are taken into...
A Semi-Emperical Model for Small Starin Shear Modulus of Unsaturated Low Plasticity Soils
, M.Sc. Thesis Sharif University of Technology ; Khosravi, Ali (Supervisor)
Abstract
The shear modulus of soils is a key material quantity which is frequently used in the evaluation of wave propagation through soil layers in dynamic response analyses for many geotechnical systems. The shear modulus, G, is defined as the slope of the shear stress-strain hysteresis loop and is significantly influenced by the shear strain amplitude induced in a soil specimen. Of particular interest in geotechnical engineering, the value of shear modulus for strains less than 10-6 defined as the small strain shear modulus, Gmax. The early experimental studies on the shear modulus of water-saturated or dry soil showed that shear modulus is highly dependent on mean effective sress, p´, and void...
Effect of DEM Resolution on Hydraulic Modeling of Flood Inundation Area: Case Study of Gorganrood River, Northeast of Iran
, M.Sc. Thesis Sharif University of Technology ; Ataie Ashtiani, Behzad (Supervisor)
Abstract
Digital Elevation Models (DEM) is a crucial element of hydraulic models, including floods. Due to the lack of high-precision topographic data, including ground-based mapping hydraulic modeling is challenging. In recent years, remote sensing data, extensively used by many researchers in hydraulic modeling due to global coverage and free access. One of the most critical questions in hydraulic modeling is the efficiency of these DEMs in flood simulation. This research focused on using remote-sensing-based DEMs, such as SRTM-30m and 90m, ASTER-30m, and ALOS-12.5m DEMs, on the performance of the HEC-RAS-2D model in the Gorganrood river.The results showed that ALOS and SRTM-30m DEMs' accuracy and...
Impact of Stress on Permeability of Packed Hydraulic Fracture
, M.Sc. Thesis Sharif University of Technology ; Shad, Saeed (Supervisor) ; Fatemi, Mobeen ($item.subfieldsMap.e)
Abstract
Given the broad role of oil and gas playing in the world economy, finding the hydrocarbon reservoir that economically is affordable is quite significant. Some of the unconventional oil and gas reservoirs are important from the economic point of view since they produce insufficient hydrocarbon due to either low permeability or damage during drilling and production. Hydraulic fracturing is one of the most significant methods for improving the productivity of wells and reservoirs. Hydraulic fracturing acts by affecting on reservoir rock physic. In the current century, this approach has an essential effect in enhancing the permeability and production of reservoirs by creating, extending and...
Effects of Microstructure and Salinity Concentration on Hydraulic Conductivity of Silty Clay Soils
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
Various contaminants and their leachate, when they penetrate into the soil, cause changes in soil microstructure, this change in microstructure leads to changes in soil permeability and volume. In this study, first, the effects of soil microstructure change on the hydraulic conductivity of saturated soil were investigated using the change in initial saturation degree during compaction for compacted samples and the change in sample construction in reconstituted samples. Also, the simultaneous effect of changing the initial microstructure and salt solution on the hydraulic conductivity of saturated silty clay soils using a three-axial permeability device with the ability to measure volume...
XFEM modeling of the effect of in-situ stresses on hydraulic fracture characteristics and comparison with KGD and PKN models
, Article Journal of Petroleum Exploration and Production Technology ; 2022 ; 21900558 (ISSN) ; Pak, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Increasing the permeability of hydrocarbon reservoirs by creating artificial cracks that are induced by injection of fluids under high pressure is called hydraulic fracturing (HF). This method is widely used in petroleum reservoir engineering. For design of Hydraulic Fracture operations, several analytical models have been developed. KGD and PKN are the first and most used analytical models in this area. Although number of advanced softwares are developed in recent years, KGD and PKN models are still popular and have even been used in a number of softwares. In both models the characteristics of the fracture namely: fracture length (L), fracture width (w), and fluid pressure at the crack...
Web page clustering using harmony search optimization
, Article IEEE Canadian Conference on Electrical and Computer Engineering, CCECE 2008, Niagara Falls, ON, 4 May 2008 through 7 May 2008 ; 2008 , Pages 1601-1604 ; 08407789 (ISSN) ; 9781424416431 (ISBN) ; Mahdavi, M ; Kangavari, M ; Safarkhani, B ; Sharif University of Technology
2008
Abstract
Clustering has become an increasingly important task in modern application domains. Targeting useful and relevant information on the World Wide Web is a topical and highly complicated research area. Clustering techniques have been applied to categorize documents on web and extracting knowledge from the web. In this paper we propose novel clustering algorithms based on Harmony Search (HS) optimization method that deals with web document clustering. By modeling clustering as an optimization problem, first, we propose a pure HS based clustering algorithm that finds near global optimal clusters within a reasonable time. Then we hybridize K-means and harmony clustering to achieve better...
Water hammer in a horizontal rectangular conduit containing air-water two-phase slug flow
, Article Journal of Hydraulic Engineering ; Volume 142, Issue 3 , 2016 ; 07339429 (ISSN) ; Borghei, S. M ; Kabiri Samani, A ; Sharif University of Technology
American Society of Civil Engineers (ASCE)
2016
Abstract
The study of water hammer in air-water, two-phase flows in hydraulic structures such as pressurized pipelines and tunnels, siphons, culverts, and junctions is of great importance for design purposes. Water hammer if combined with a periodic slug flow would lead to severe periodic transient pressure fluctuations inside the conduit. Laboratory experiments have been conducted to investigate waterhammer pressure inside a horizontal rectangular conduit carrying a two-phase, air-water slug flow. Tests were performed in an experimental apparatus comprising a 6.8-m-long transparent pipeline 0.06 m wide and 0.1 m high. By rapidly closing a control gate at the end of the conduit, propagating pressure...
Validation and inter-comparison of models for landslide tsunami generation
, Article Ocean Modelling ; Volume 170 , 2022 ; 14635003 (ISSN) ; Grilli, S. T ; Horrillo, J ; Liu, P.L.-F ; Nicolsky, D ; Abadie, S ; Ataie-Ashtiani, B ; Castro, M.J ; Clous, L ; Escalante, C ; Fine, I ; González-Vida, J.M ; Løvholt, F ; Lynett, P ; Ma, G ; Macías, J ; Ortega, S ; Shi, F ; Yavari Ramshe, S ; Zhang, C ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The Mapping and Modeling Subcommittee of the US National Tsunami Hazard Mitigation Program convened a workshop in January 2017 to evaluate the present state of numerical models for the simulation of tsunamis generated by submarine or subaerial landslides. A range of benchmark tests were provided to participants, with three tests emphasized: (i) a laboratory submarine solid slide in a 2D horizontal tank, (ii) a laboratory submarine granular slide in a 1D flume, and (iii) a field case based on submarine slides which occurred in Port Valdez, AK during the 1964 Alaska earthquake. Nine landslide tsunami models configured with 21 different combinations of physical options were benchmarked,...
Unidirectional transport of water through an asymmetrically charged rotating carbon nanotube
, Article Journal of Physical Chemistry C ; Volume 121, Issue 42 , 2017 , Pages 23649-23658 ; 19327447 (ISSN) ; Moosavi, A ; Sharif University of Technology
Abstract
Achieving a high speed, unidirectional water flow through carbon nanotubes (CNTs) is a key factor in designing novel nanofluidic devices. In this study, utilizing molecular dynamics (MD) simulations, we propose a novel nanoscale water pump for directed water transportation using charged rotating CNTs. Two basic conditions for stable water flow, including thermodynamic nonequilibrium and spatial asymmetry, are provided by introducing partial charges on carbon atoms of the channel with asymmetric patterns and its rotation, respectively. We demonstrate that the performance of the water pump is proportional to the gradient of a linear charge distribution and angular velocity of the rotation. Our...
Uncertainty analysis for seawater intrusion in fractured coastal aquifers: Effects of fracture location, aperture, density and hydrodynamic parameters
, Article Journal of Hydrology ; Volume 571 , 2019 , Pages 159-177 ; 00221694 (ISSN) ; Fahs, M ; Ataie Ashtiani, B ; Belfort, B ; Simmons, C. T ; Younes, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this study we use polynomial chaos expansion (PCE) to perform uncertainty analysis for seawater intrusion (SWI) in fractured coastal aquifers (FCAs) which is simulated using the coupled discrete fracture network (DFN) and variable-density flow (VDF) models. The DFN-VDF model requires detailed discontinuous analysis of the fractures. In real field applications, these characteristics are usually uncertain which may have a major effect on the predictive capability of the model. Thus, we perform global sensitivity analysis (GSA) to provide a preliminary assessment on how these uncertainties can affect the model outputs. As our conceptual model, we consider fractured configurations of the...
Two-dimensional model for lateral intake flows
, Article Proceedings of the Institution of Civil Engineers: Water Management ; Volume 158, Issue 4 , 2005 , Pages 141-150 ; 17417589 (ISSN) ; Taher Shamsi, A ; Sadeghi Bagheney, M ; Mohamadian, A ; Sharif University of Technology
ICE Publishing
2005
Abstract
This paper gives details of the refinement and application of a two-dimensional horizontal model for rivers. An explicit finite-difference algorithm was used for solving the governing differential equations, which includes the conservation of mass and momentum to predict hydrodynamic parameters. The model includes different turbulence closure models - that is, constant eddy viscosity, Prandtl simple mixing length and Smagorinsky methods. An experimental programme was designed and carried out in a laboratory flume to measure the length of eddy produced at the entrance of the intake. Model predictions have been compared with experimental results for a lateral intake. The effect of different...
Tuneable vibration absorber design to suppress vibrations: An application in boring manufacturing process
, Article Journal of Sound and Vibration ; Volume 318, Issue 1-2 , 2008 , Pages 93-108 ; 0022460X (ISSN) ; Bakhtiari Nejad, F ; Movahhedy, M. R ; Sharif University of Technology
2008
Abstract
Dynamic vibration absorbers are used to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges, etc. Tuneable vibration absorbers (TVA) are also used as semi-active controllers. In this paper, the application of a TVA for suppression of chatter vibrations in the boring manufacturing process is presented. The boring bar is modeled as a cantilever Euler-Bernoulli beam and the TVA is composed of mass, spring and dashpot elements. In addition, the effect of spring mass is considered in this analysis. After formulation of the problem, the optimum specifications of the absorber such as spring stiffness, absorber...
Truck scheduling in cross-docking warehouse including multiple dock doors
, Article Proceedings of International Conference on Computers and Industrial Engineering, CIE ; Volume 2 , October , 2013 , Pages 746-758 ; 21648689 (ISSN) ; 9781629934372 (ISBN) ; Darvishan, J. A ; Sharif University of Technology
Curran Associates Inc
2013
Abstract
Cross-docking is a new logistic technique that brings considerable benefits such as low inventory level, customer satisfaction, etc. To achieve these benefits, coordination between transportation facilities is quite important. This paper studies both inbound and outbound scheduling problem and assignment of products from inbound truck to outbound trucks in a cross-docking warehouse including multiple receiving and shipping dock doors. To do so, an MILP model is developed, which is NP-hard. Thus, a GA algorithm is developed and has been strengthened with two proposed neighborhood search to tackle the developed problem in medium and large size instances. Finally, numerical results of three...
Treatment of olive mill wastewater by rotating biological contactor reactor
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Nazemi, A ; Sharif University of Technology
2006
Abstract
The removal performance of total poly phenols and orthodiphenols (o-diphenols) content in olive mill waste (OMW) was investigated with a three stages cross flow laboratory scale rotating biological contactor (RBC) in the present study. Due to high COD and other pollutant existed in the original OMW, before biological treatment of OMW by the RBC system, physico-chemical treatment was effected for COD and other pollutant reduction. Inoculation of RBC was effected by sludge from olive oil factory, and microbial acclimation was continued to 49 days and the system was adapted to about 300ppm of OMW poly phenols and o-diphenols. In biological treatment, effect of operating parameters such as...
Toward a comprehensive microextraction/determination unit: A chip silicon rubber polyaniline-based system and its direct coupling with gas chromatography and mass spectrometry
, Article Journal of Separation Science ; Volume 39, Issue 21 , 2016 , Pages 4227-4233 ; 16159306 (ISSN) ; Allahdadlalouni, M ; Zamani, C ; Sharif University of Technology
Wiley-VCH Verlag
2016
Abstract
An inexpensive silicon rubber-based chip was constructed by fabricating a triangle-shaped microcanal with a 135 μm width and 234 μm depth by laser ablation technique. The fabricated groove was sealed by a thin glass cover while two pieces of stainless-steel tubing were connected to each side of the canal. Then, a thin polyaniline film was synthesized on the walls of the canal by chemical oxidation using a syringe pump to deliver the relevant reagents. The microfluidic system was eventually connected to a gas chromatography-mass spectrometry. To evaluate the capability of the constructed microfluidic system, it was implemented to the analysis of submilliliter volumes of environmental samples...
Three-dimensional modeling of density current in a straight channel
, Article Journal of Hydraulic Engineering ; Volume 135, Issue 5 , 2009 , Pages 393-402 ; 07339429 (ISSN) ; Afshin, H ; Aram, E ; Sharif University of Technology
2009
Abstract
Dense underflows are continuous currents that move downslope due to their density being heavier than that of the ambient water. In this work, a steady density current with a uniform velocity and concentration from a narrow sluice gate enters into a wide channel of lighter ambient fluid and moves forward downslope. Experiments varying inlet velocity and concentration and hence inlet Richardson numbers were conducted. Numerical simulations were also performed with a low-Reynolds number k-ε model. The results of numerical simulation agree well with the experimental data. © 2009 ASCE