Search for: fluid-mechanics
Total 60 records
Simulation of elasto-plastic deformations in composites by flow rules, Article Indian Journal of Science and Technology ; Vol. 7, issue. 2 , 2014 , pp. 180-184 ; ISSN: 09746846 ; Fazaeli, D ; Daneshmand, S ; Shafaghatian, N ; Sharif University of Technology
In this paper, a novel model is proposed to predict stress behavior in the fibrous polymer composites under an applied tensile axial loading. Tangential stress is obtained by simulating between polymeric matrix flow (polyester) and fluid flow. In the other words, creep behavior of the petrochemical material or polymeric resin (matrix) is modeled using fluid flow theory. Furthermore, behavior of the shear stress is predicted by suitable mathematical functions. Finally, important relation is extracted by combining the solid and fluid mechanics formulations
A note on the resonant interaction between a surface wave and two interfacial waves, Article Journal of Fluid Mechanics ; Volume 491 , 2003 , Pages 1-9 ; 00221120 (ISSN) ; Lawrence, G. A ; Seymour, B ; Sharif University of Technology
Cambridge University Press 2003
Hill & Foda (1998) and Jamali (1998) have presented theoretical and experimental studies of the resonant interaction between a surface wave and two oblique interfacial waves. Despite many similarities between the findings there is one seemingly major difference. Hill & Foda's (1998) analysis indicated that there are only narrow bands of frequency, density ratio and direction angle within which growth is possible. On the other hand, Jamali (1998) predicted and observed wave growth over wide ranges of frequency and direction angle, and for all the density ratios that he investigated. We show that Hill & Foda's (1998) second-order representation of the dynamic interfacial boundary condition is...
Theoretical-experimental investigation of Co emission from an oil refinery incinerator, Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM ; Vol. 1C, issue , 2014 ; Abrar, B ; Yazdi, M. K ; Zeinali, M ; Schneider, G. E ; Sharif University of Technology
In this paper, we investigate the CO emission from an oil refinery gas incinerator both theoretically and experimentally. At the beginning of this research, our collected data from this incinerator showed that the CO contamination would be far exceeding the permissible environmental standards at the stack exhaust. Therefore, we decided to perform a combined theoretical-experimental study to find a reasonable solution to reduce the CO pollution suitably. Our theoretical study showed that a reliable solution would be to increase the incinerator operating temperature. However, we needed to collect some data from this incinerator to examine if our achieved analytical solution would work...
Experimental study and modeling of gravity drainage during WAG process in fractured carbonate rocks, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 27, Issue 3 , October , 2008 , Pages 103-113 ; 10219986 (ISSN) ; Badakhshan, A ; Taghikhani, V ; Rashtchian, D ; Gotbi, C ; Sajadian, V. A ; Sharif University of Technology
The experimental study and modeling of gravity drainage during Water Alternative Gas Injection, WAG process, in carbonate rock for one of the Iranian off-shore reservoir at lab-scale were carried out. The mechanism of gravity drainage during the WAG process, and its contribution to the oil recovery in the fractured carbonate reservoirs were also studied. In the WAG process alternatively gas is injected during the process and gravity drainage could be happened. Changes in the block dimensions, rock properties, oil properties, gas properties, and fractures properties and their effect on the amount of oil recovered during the gravity drainage mechanism were studied. It would be worth mentioning...
Analytical solution for contact problem between a tilted wedge and half-plane under partial slip condition, Article Materials and Design ; Volume 29, Issue 7 , 2008 , Pages 1291-1299 ; 02613069 (ISSN) ; Naderi, D ; Sharafbafi, F ; Sharif University of Technology
Elsevier Ltd 2008
Elastic contact problem of a tilted shallow wedge with a half-plane is considered. The problem is solved analytically in either full slip or partial slip conditions. Closed-form expression is given for the Muskhelishvili's potential function of the contact. In the partial slip condition, the locations of the stick and slip zones were given explicitly in terms of the applied external loads and coefficient of friction. The results have been compared with finite elements modelling results. © 2007 Elsevier Ltd. All rights reserved
Calculation of thermodynamic properties of simple fluids using a new derived pair correlation function, Article Fluid Phase Equilibria ; Volume 254, Issue 1-2 , 2007 , Pages 138-143 ; 03783812 (ISSN) ; Parsafar, G. A ; Najafi, B ; Sharif University of Technology
Based on a new derived radial distribution function (RDF) for potentials with a hard-core we have presented in this paper a method to apply the derived RDF for calculating thermodynamic properties of real fluids up to moderate densities. In order to use the derived RDF for real fluids, one of the potential parameters is chosen in such a way that the RDF behaves more like that for a real fluid. Hence we have been able to calculate all thermodynamic properties of a simple fluid analytically. We have then applied our procedure to a Lennard-Jones fluid and compared the results with simulation data. The agreement is good up to moderate densities, i.e. ρ* ≤ 0.6, which lies in the liquid range of...
Comparison of interface capturing methods in two phase flow, Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 29, Issue 6 , 2005 , Pages 539-548 ; 03601307 (ISSN) ; Jahanbakhsh, E ; Seif, M. S ; Sharif University of Technology
In two phase flow investigation, there is a need for robust methods capable of predicting interfaces, in addition to treating the traditional governing equations of fluid mechanics (Navier-Stokes Eqs.). Such methods in a finite volume approach can be classified into two typical categories called interface tracking and interface capturing methods. According to their abilities, interface capturing methods are of more interest in free surface modeling, especially when complex interface topologies such as wave breaking are included. These methods solve a scalar transport equation in order to find the distribution of two phases all over the computational domain. That is, all properties of the...
Numerical analysis of coherent structures in bidirectional swirl combustion chamber, Article Computational Thermal Sciences ; Volume 8, Issue 3 , 2016 , Pages 265-289 ; 19402503 (ISSN) ; Keshavarz, P. M ; Saidi, M. H ; Sharif University of Technology
Begell House Inc
Analysis and identification of vortex structures and their formation, particularly in swirl flows, have received widespread interest among researchers in the field of fluid mechanics. Due to the importance of vortex structures and their applications in combustion chambers, a special type of combustion chamber, which is called a “bidirectional swirl combustor,” has been investigated in this work. The dependence of vortex structures on the combustion chamber geometry and fuel injection location in cold flow, the effect of hot flow on coherent structures, and the difference between vortex structures in hot and cold flows have been studied as well. A common characteristic which is in combustion...
Discharge capacity of conventional side weirs in supercritical conditions, Article 4th European Congress of the International Association of Hydroenvironment engineering and Research, IAHR 2016, 27 July 2016 through 29 July 2016 ; 2016 , Pages 658-664 ; 9781138029774 (ISBN) ; Jalili Ghazizadeh, M. R ; Kabiri Samani, A ; Nekooie, M. A ; Sharif University of Technology
CRC Press/Balkema 2016
Side weirs are widely used for level control and flow regulation in hydraulic engineering applications such as irrigation, land drainage, and sewer systems. These hydraulic structures allow a part of the flow to spill laterally when the surface of the flow in the main channel rises above the weir crest. The supercritical flow over a side-weir is a typical case of spatially varied flow with decreasing discharge. This study is aimed at investigating the variations of specific energy along the side-weir using experimental results. Some diagrams have been presented in terms of dimensionless ratio of diverted discharge to total discharge. These diagrams which can be used in the design of side...
Developing consistent inlet thermal boundary condition in micro/nano scale channels with heat transfer, Article 1st ASME Micro/Nanoscale Heat Transfer International Conference, MNHT08, Tainan, 6 January 2008 through 9 January 2008 ; Volume Parts A and B , 2008 , Pages 691-700 ; 0791842924 (ISBN); 9780791842928 (ISBN) ; Vakilipour, S ; Sharif University of Technology
In this work, we present a more realistic inlet boundary condition to simulate compressible and incompressible flows through micro and nano channels considering consistent momentum and heat transfer specifications there. At solid walls, a constant wall temperature with suitable jump is applied as the wall thermal boundary condition; however, two types of thermal inlet boundary conditions are investigated at the inlet. We firstly examine the classical inlet boundary condition, which specifies a uniform temperature distribution right at the real inlet. Alternatively, we apply the same boundary condition but at a fictitious place far upstream of the real channel inlet. To validate our results,...
Exchange flow between a canopy and open water, Article Journal of Fluid Mechanics ; Volume 611 , 25 September , 2008 , Pages 237-254 ; 00221120 (ISSN) ; Zhang, X ; Nepf, H. M ; Sharif University of Technology
This paper theoretically and experimentally investigates the exchange flow due to temperature differences between open water and a canopy of aquatic plants. A numerical model is used to study the interfacial shape, frontal velocity and total volumetric exchange, and their dependence on a dimensionless vegetation drag parameter. The numerical predictions are consistent with the laboratory measurements. There is a short initial period in which the force balance is between buoyancy and inertia, followed by drag-dominated flow for which there is a balance between buoyancy and drag forces. After the initial stage, the gravity current propagating into the canopy takes a triangular shape whereas...
A perspective on electrostatics in gas-solid fluidized beds: Challenges and future research needs, Article 13th International Conference on Fluidized Bed Technology, CFB 2021, 10 May 2021 through 14 May 2021 ; 2021 , Pages 426-431 ; 9781771368506 (ISBN) ; Bi, X. T ; Grace, J. R ; Sharif University of Technology
GLAB Reactor and Fluidization Technologies 2021
This paper provides a perspective on the current knowledge and potential areas of future research related to electrostatics in fluidized beds. Aspects addressed include characterization techniques, interplay between electrostatics and hydrodynamics, charge control methods, applications of tribo-electrostatic fluidization systems, and computational simulations which account for electrostatic forces, as well as other forces. This is a complex research field involving fluid mechanics, powders, and electrical physics. © 2021 CFB 2021 - Proceedings of the 13th International Conference on Fluidized Bed Technology. All rights reserved
Air Pollution Modeling, Using AERMOD Model Coupled with OpenFOAM Software, M.Sc. Thesis Sharif University of Technology ; Tayyebi Rahni, Mohammad ; Rashidi, Yousef
Over the course of past decade, air pollution has been placed among the top issues chocking capital Tehran. Stationary source of air pollution is among the most important, but, less treated facors. On the year, 2014, Tehran’s air quality company addressed a number of projects in this very field could gain further governmental supports. This announcement could be a sign, showing the importance of this research. These researches in fact, have the potentioal to increase the authority’s decision making abilities in critical situations. As the models prognosticates future with acceptble accuracy, it leads to highly efficient dicissions. The results could also be used in demographic studies as...
Reacting turbulent flow simulation to improve the mixing process in an oil refinery incinerator, Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM ; Vol. 1C, issue , August , 2014 ; ISBN: 9780791846230 ; Abrar, B ; Barezban, M. B ; Faridvand, A ; Schneider, G. E ; Sharif University of Technology
Combustion emission is one of the most important issues in the design of industries. Todays' strict environmental standards have limited the productions of CO, NOx, SOx, and other hazardous pollutants from the related industries. In this work, we study a typical oil refinery incinerator, which is used to burn waste gases residue produced during bitumen production process. The waste gas mainly includes a mixture including N2, H2O-vapor, and O2 species. Additionally, there are significant amounts of CO species and CxHy droplets in the waste gas composition. The measurements show that the CO emission becomes so crucial in high flow rate of feeding waste gas to the incinerator. Here, we...
Numerical investigation of thermo fluid mechanics of differentially heated rotating tubes, Article Heat Transfer Engineering ; Volume 31, Issue 3 , 2010 , Pages 201-211 ; 01457632 (ISSN) ; Farhanieh, B ; Sharif University of Technology
Three-dimensional simulation of incompressible flow in rotating tubes for both laminar and turbulent flows has been performed using a finite-volume method for elliptic flows. The influence of Reynolds number on the velocity field and the effects of temperature gradient on temperature profiles have been presented by numerical simulations. Also the effects of velocity field, flow regime, and temperature distribution along the tube have been studied from different points of view. The results have been calculated for rotational Reynolds numbers ranging from 1000 to 320,000. The comparisons between numerically calculated velocity field and the Nusselt number have shown satisfactory agreement with...
Evaluation of seepage problem under a concrete dam with finite volume method, Article Proceedings of the 7th IASME / WSEAS International Conference on Fluid Mechanics and Aerodynamics, FMA '09, 20 August 2009 through 22 August 2009 ; 2009 , Pages 34-40 ; 9789604741069 (ISBN) ; Abdi Dezfuli, E ; Zebardast, A ; Sharif University of Technology
In most of countries, underground waters are the most important sources to provide drinking water. So it is necessary to make scheme and to do high protection of to achieve maximum beneficiary. Necessity of this management is going to be felt by developing these sources and human's interference. However, in the past overtopping phenomenon was the first reason of dam's destruction, but nowadays by increasing of spate design's period, the significant problem that researchers are interfere with, is seepage problem. The purpose of solving the underground problems is to procure height of water as a function of coordinate and time. In observation of practical industries, we can use the...
An experimental investigation of the reduced frequency effects into pressure coefficients of a plunging airfoil, Article 7th International Conference on Advances in Fluid Mechanics, AFM'08, The New Forest, 21 May 2008 through 23 May 2008 ; Volume 59 , 2008 , Pages 153-161 ; 17433533 (ISSN); 9781845641092 (ISBN) ; Ajalli, F ; Soltani, M. R ; WIT Transactions on Engineering Sciences ; Sharif University of Technology
Aerodynamic coefficients on a two dimensional plunging airfoil, in a low-speed wind tunnel are presented. Dynamic motion was produced by plunging the model over a range of reduced frequencies, and mean angles of attack. The Reynolds number in the present test was held fixed (Re = 1.5×10 5), and the reduced frequency was varied in an almost wide range. Surface static pressure distribution was measured on the upper and lower sides of the model, during the oscillating motion. It was found that reduced frequency had strong effects on the pressure distribution, near the leading edge of the airfoil. For mean equivalent angles of attack of 0, 5 degrees, hysteresis loops on the upper surface of the...
Details study of ambient wind effect on heat dissipation capacity of thermal-powerplant dry cooling-towers, Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM ; Volume 1A , August 3–7 , 2014 , pp. V01AT03A017 ; ISSN: 08888116 ; ISBN: 9780791846216 ; Behrouzifar, A ; Mirhashemi, A ; Salemkar, H ; Schneider, G. E ; Sharif University of Technology
Thermal powerplants report a reduction in their dry cooling tower performances due to surrounding wind drafts. Therefore, it is very important to consider the influence of wind velocity in cooling tower design; especially in geographical points with high wind conditions. In this regard, we use the computational fluid dynamics (CFD) tool and simulate a dry cooling tower in different wind velocities of 0, 5 and 10 m/s. To extend our calculations; we also consider the temperature variation of circulating water through the tower heat exchanger or deltas one-by-one. We show that some heat exchangers around the tower cannot reduce the circulating water temperature sufficiently. This causes an...
Experimental analysis of secondary gas injection strategies, Article Petroleum Science and Technology ; Volume 31, Issue 8 , 2013 , Pages 797-802 ; 10916466 (ISSN) ; Alizadeh, N ; Kharrat, R ; Ghazanfari, M. H ; Laki, A. S ; Sharif University of Technology
CO2 injection is a potentially viable method of enhanced oil recovery for medium oil reservoirs. The authors compare the effect of gas injection strategy (simultaneous water-alternating gas [SWAG], water-alternating gas [WAG], and continuous gas injection [CGI]) on recovery in immiscible, near-miscible, and miscible modes of injection. It has been proved that CGI is not the most efficient injection scenario in oil-wet reservoirs. Miscible and near-miscible core flood tests demonstrated high oil recoveries in all injection strategies due to high capillary numbers achieved as a result of miscibility. The fluid mechanics of floods were discussed using pressure drop data, different mechanics was...
Entropy minimization in turbine cascade using continuous adjoint formulation, Article Engineering Optimization ; Volume 48, Issue 2 , 2016 , Pages 213-230 ; 0305215X (ISSN) ; Mazaheri, K ; Sharif University of Technology
Taylor and Francis Ltd
A complete continuous adjoint formulation is presented here for the optimization of the turbulent flow entropy generation rate through a turbine cascade. The adjoint method allows one to have many design variables, but still afford to compute the objective function gradient. The new adjoint system can be applied to different structured and unstructured grids as well as mixed subsonic and supersonic flows. For turbulent flow simulation, the k-ω shear-stress transport turbulence model and Roe's flux function are used. To ensure all possible shape models, a mesh-point method is used for design parameters, and an implicit smoothing function is implemented to avoid the generation of non-smoothed...