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experimental-and-numerical-studies
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Experimental and numerical studies on resistance of a catamaran vessel with non-parallel demihulls
, Article Scientia Iranica ; Vol. 21, Issue. 3 , 2014 , pp. 600-608 ; ISSN: 2345-3605 ; Rad, M ; Hajilouy, A ; Sharif University of Technology
Abstract
In common catamaran vessels, demihulls are parallel to each other. In this paper, the total resistance of a catamaran vessel with non-parallel demihulls is investigated experimentally and numerically. Experiments are carried out at different Separation Ratios (S.R.), that is the ratio of fore to aft separation of the catamaran demihullsand also in two ratios of length to separation in amidships (L/Sm). The FLUENT solver, based on the Finite Volume Method (FVM), was used for numerical solution. Applying the VOF model, the free surface around the catamaran vessel and total resistance are calculated and compared with experimental results. Finally, the frictional resistance of the catamaran from...
The seismic performance of new detailing for RCS connections
, Article Journal of Constructional Steel Research ; Volume 91 , 2013 , Pages 76-88 ; 0143974X (ISSN) ; Attari, N. K. A ; Kazemi, M. T ; Sharif University of Technology
2013
Abstract
Over the past few decades considerable experimental and numerical studies have been conducted on the Reinforced Concrete columns to Steel beams (RCS) connections. Most of those researches have focused on studying the joint failure modes and ultimate joint strength of specimens utilizing strong beams and columns with weak joints. In this paper, two interior RCS connections were designed based on the Strong Column-Weak Beam (SCWB) criterion. Both specimens were tested under quasi-static reversed cyclic loading. The tested specimens were modeled by a finite element method, which verified with experimental results. Several models with different joint details were investigated using the verified...
Experimental and numerical study of the effect of pulsating flow on the turbocharger turbine performance parameters
, Article SAE Technical Papers ; Volume 2 , April , 2013 ; Boroomand, M ; Taeibi Rahni, M ; Sharif University of Technology
2013
Abstract
The pulsating flow in the exhaust gas of a SI engine causes an unsteady flow at the inlet to the turbocharger turbine. In a four cylinder four stroke engine, the pulse frequency varies between 20 and 200 Hz. Three dimensional pulsating flows in a vane-less turbocharger turbine of a 1.7 liters SI engine are simulated numerically and validated experimentally. Simulations are done for 720 degree engine cycle at three engine speeds. The results are shown the inlet pulsating flow has significant effects on several turbine parameters especially the inlet total pressure, the reduced mass flow rate and the efficiency. The results show a very good agreement between the three-dimensional unsteady...
Analysis of nanoparticles migration on natural convective heat transfer of nanofluids
, Article International Journal of Thermal Sciences ; Volume 68 , June , 2013 , Pages 79-93 ; 12900729 (ISSN) ; Yaghoubi, M ; Sharif University of Technology
2013
Abstract
Both experimental and numerical studies are unanimous for enhancing Nusselt number for forced convection of nanofluids with slight difference, but there is inconsistency for natural convection heat transfer of nanofluids. In this paper attempt is made to study the effects of nanoparticles migration on the natural convection behavior of nanofluids. For analysis, a mixture model is used by including important phenomena such as Brownian motion and thermophoresis effects. These two mechanisms are taken into account to compute the slip velocities between the base fluid and nanoparticles. The governing equations are solved numerically and good agreements are observed in comparison with...
Experimental and numerical study on heat transfer characteristics for methane/air flame impinging on a flat surface
, Article International Journal of Thermal Sciences ; Volume 110 , 2016 , Pages 229-240 ; 12900729 (ISSN) ; Momeni, A ; Ebrahimi Fordoei, E ; Ashjaee, M ; Sharif University of Technology
Elsevier Masson SAS
2016
Abstract
Heat flux from a premixed methane/air slot laminar flame jet impinging upward to a horizontal target plate is studied experimentally and numerically. Mach-Zehnder interferometer is used to obtain the overall temperature field. The flame jet is produced by a slot nozzle with length of L = 25 mm and width of W = 3 mm. The slot nozzle is parallel to the target plate which has the dimensions of 250 × 130 × 10 mm. The experimentally obtained heat flux distributions were compared for different firing rates and nozzle to plate spacing. A second peak in heat flux to the target surface (an off-center peak with respect to the axis of the nozzle) was observed for the shortest spacing and highest firing...
A comprehensive experimental and numerical study on redistribution of residual stresses by shot peening
, Article Materials and Design ; Volume 90 , 2016 , Pages 478-487 ; 02641275 (ISSN) ; Ghasemi, A ; Farrahi, G. H ; Sherafatnia, K ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Shot peening is one of the most effective surface strengthening treatment technologies in which compressive residual stresses are induced beneath the specimen surface. Effects of various factors on the distribution of residual stress profile induced by shot peening have been investigated by many researchers. However, initial residual stresses are one of the important factors which affect the shot peening residual stress.This study is aimed to present comprehensive numerical and experimental study on the effect of initial residual stresses on the shot peened specimen. Initial residual stresses were induced using a four-point bending rig and grinding. Incremental center hole drilling (ICHD)...
Experimental and numerical study of shear crack propagation in concrete specimens
, Article Computers and Concrete ; Volume 20, Issue 1 , 2017 , Pages 57-63 ; 15988198 (ISSN) ; Sarfarazi, V ; Bagher Shemirani, A ; Sharif University of Technology
Abstract
A coupled experimental-numerical study on shear fracture in concrete specimens with different geometries is carried out. The crack initiation, propagation and final breakage of concrete specimens are experimentally studied under compression loading. The load-strain and the strength of the specimens are experimentally measured, indicating decreasing effects of the shear behavior on the failure load of the specimen. The effects of specimen geometries on the shear fracturing path in the concrete specimens are also investigate. Numerical models using an indirect boundary element method are made to evaluate the crack propagation paths of concrete specimens. These numerical results are compared...
Experimental and numerical studies on ribbed bracing system
, Article Structural Design of Tall and Special Buildings ; Volume 27, Issue 13 , 2018 ; 15417794 (ISSN) ; Toufigh, V ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
Ribbed bracing system (RBS) is an innovative structural system designed to eliminate the buckling of braces and enhance the behavior of structures under seismic loads. In this study, a collaborative performance of 2 RBS devices bracing a frame was assessed numerically and experimentally. In the numerical phase, the collaboration of ribbed braces at various stages of reversal loading was elaborated mathematically and was used for representing the system using finite element modeling. In the next phase, the numerically observed behavior was validated experimentally by conducting cyclic quasistatic tests of the proposed configurations. Two alternative RBS configurations—called completely closed...
Experimental and numerical study on a novel ribbed bracing system
, Article Advances in Structural Engineering ; Volume 21, Issue 9 , 2018 , Pages 1349-1360 ; 13694332 (ISSN) ; Fallah, S ; Sahafipourfard, M. A ; Arzeytoon, A ; Toufigh, V ; Sharif University of Technology
SAGE Publications Inc
2018
Abstract
In this article, the ribbed bracing system is proposed and evaluated through experimental and numerical studies. Ribbed bracing system is composed of a supplemental part with ribbed interfaces that is attached to a brace member and allows for its free length reduction to prevent the development of compressional forces responsible for buckling of the brace. Ribbed bracing system provides two different mechanisms: completely closed ribbed bracing system and improved-centering ribbed bracing system which are validated, in this study, through design, fabrication, and testing of small-scale specimens subjected to cyclic quasi-static loading. As verified by the test results, in improved-centering...
An innovative infill wall utilizing light expanded clay aggregate: An experimental and numerical study
, Article Structural Design of Tall and Special Buildings ; Volume 29, Issue 15 , 2020 ; Khaloo, A ; Sharif University of Technology
John Wiley and Sons Ltd
2020
Abstract
Past earthquakes had shown vulnerability of infill walls especially under out of plane (OOP) loading. Although some new infill walls show a good OOP performance, generally, they do not have the right economic justification or have complexity in construction. Therefore, in this paper, an innovative economical infill wall is presented that is not complicated in construction. The proposed wall constructed by light expanded clay aggregate in especial shape that reinforced with side plates, top, and bottom rebars. Experimental and numerical studies were carried out to investigate its seismic performance. Experimental results showed a high continuity between blocks of wall due to its especial...
Experimental and numerical study of the gas-gas separation efficiency in a Ranque-Hilsch vortex tube
, Article Separation and Purification Technology ; Vol. 138, issue , Dec , 2014 , p. 177-185 ; Farhadi, F ; Sharif University of Technology
Abstract
A brass vortextube is used to carry out a series of experiments. The main objective of the present research is to investigate the separation performances of a vortex tube (VT) for a hydrocarbon mixture. Examination is also applied to study the effects of nozzle intakes number and cold fraction on the gas species separation at specific inlet pressure 236.37 kPa in a VT with two gas mixtures (LPG as a hydrocarbon mixture and LPG-N2). A two-dimensional computational fluid dynamic (CFD) model simulation of a VT is presented. CFD code after validation is also applied to investigate the role of cold fraction and nozzle intakes number on the gas species separation. The highly rotating flow field...
Mixed-convection flow of Al2O3-H2O nanofluid in a channel partially filled with porous metal foam: Experimental and numerical study
, Article Experimental Thermal and Fluid Science ; Vol. 53 , February , 2014 , pp. 49-56 ; ISSN: 08941777 ; Molaei Dehkordi, A ; Sharif University of Technology
Abstract
Mixed-convection flow of nanofluids inside a vertical rectangular channel partially filled with open-cell metal foam and subject to a constant wall-heat flux was investigated experimentally and numerically. Al2O3-water nanofluids with different concentrations were prepared and their stability was examined using UV-Vis spectroscopy. Dynamic light scattering method was used to determine particle size distribution of the nanofluid feedstock. The outlet temperature and pressure drop were measured for different nanofluid flow rates (i.e., Reynolds number values). In the numerical section, a two-dimensional volume-averaged form of the governing equations was used. The velocity and temperature...
Multidimensional modeling of the stenosed carotid artery: A novel CAD approach accompanied by an extensive lumped model
, Article Acta Mechanica Sinica/Lixue Xuebao ; Vol. 30, issue. 2 , 2014 , p. 259-273 ; Mahdinia, M ; Firoozabadi, B ; Amirkhosravi, M ; Ahmadi, G ; Saidi, M. S ; Sharif University of Technology
Abstract
This study describes a multidimensional 3D/lumped parameter (LP) model which contains appropriate inflow/outflow boundary conditions in order to model the entire human arterial trees. A new extensive LP model of the entire arterial network (48 arteries) was developed including the effect of vessel diameter tapering and the parameterization of resistance, conductor and inductor variables. A computer aided-design (CAD) algorithm was proposed to efficiently handle the coupling of two or more 3D models with the LP model, and substantially lessen the coupling processing time. Realistic boundary conditions and Navier-Stokes equations in healthy and stenosed models of carotid artery bifurcation...
Experimental and numerical study on choosing proper pulse shapers for testing concrete specimens by split hopkinson pressure bar apparatus
, Article Construction and Building Materials ; Volume 125 , 2016 , Pages 326-336 ; 09500618 (ISSN) ; Naghdabadi, R ; Ashrafi, M. J ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Dynamic behavior of concrete specimens is investigated experimentally and numerically by split Hopkinson pressure bar (SHPB) tests. In order to accurately determine dynamic properties of brittle materials such as concrete, specimens should be subjected to particular pulse loading that can be generated by using pulse shapers. Choosing proper pulse shaper dimensions helps to obtain dynamic stress equilibrium, achieve constant strain rate and minimize pulse oscillation in the concrete specimens. To this end, SHPB tests are performed for concrete specimens and effective parameters on shaping pulses such as striker bar velocity, diameter and thickness of the pulse shaper are studied...
Multi-directional response of unreinforced masonry walls: experimental and computational investigations
, Article Earthquake Engineering and Structural Dynamics ; Volume 45, Issue 9 , 2016 , Pages 1427-1449 ; 00988847 (ISSN) ; Aref, A. J ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
This paper describes the results of an experimental and numerical study that focused on multi-directional behavior of unreinforced masonry walls and established the requisite of the related proposed design equations. The tests were conducted following several sets of multi-directional loading combinations imposed on the top plane of the wall along with considering monotonic and cyclic quasi-static loading protocols. Various boundary conditions, representing possible wall–roof connections, were also considered for different walls to investigate the influence of rotation of the top plane of the wall on the failure modes. The results of the tests were recorded with a host of high precision data...
Experimental and numerical study on the effect of aluminum foil wrapping on penetration resistance of ceramic tiles
, Article Scientia Iranica ; Volume 24, Issue 3 , 2017 , Pages 1126-1135 ; 10263098 (ISSN) ; Naghdabadi, R ; Arghavani, J ; Sharif University of Technology
Abstract
In this work, energy absorption of ceramic tiles wrapped by aluminum foil on its impact face is experimentally and numerically studied. Penetration tests as well as numerical simulations are employed to obtain Ballistic Limit Velocity (BLV) of the tiles. Experimental and numerical results yield BLV of bare tiles as 145 ± 2 and 141.5 m/s, respectively. For the wrapped tiles, these values are increased to 168 ± 2 and 162 m/s, respectively. Therefore, 13% increase in BLV of the ceramic tiles is obtained by just 2.4% increase in its weight. Moreover, it is shown that energy absorption of the wrapped tiles is at least 11% greater than that of the bare ones. Based on the results, the increase in...
How to improve the thermal performance of pulsating heat pipes: A review on working fluid
, Article Renewable and Sustainable Energy Reviews ; Volume 91 , 2018 , Pages 630-638 ; 13640321 (ISSN) ; Ahmadi, M. H ; Ghasempour, R ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Pulsating Heat Pipes (PHPs) are cooling devices that are compact in size and have an ability to transfer heat in low temperature differences. Working fluids strongly affect the thermal performance of PHPs. In this paper, effects of some thermophysical parameters relating to working fluids, such as boiling point, latent heat of vaporization, surface tension, thermal conductivity and dynamic viscosity, are presented based on experimental and numerical studies done in recent years. Addition of nanoparticles to fluids, or making nanofuild, is a new method of improving thermophysical properties of fluids. Recently, many studies are carried out on thermophysical properties of nano-fuild. Results...
Influence of diagonal stiffeners on the response of steel plate shear walls (SPSWs) considering crack propagation
, Article Bulletin of Earthquake Engineering ; Volume 17, Issue 9 , 2019 , Pages 5291-5312 ; 1570761X (ISSN) ; Foroutani, M ; Ghamari, A ; Sharif University of Technology
Springer Netherlands
2019
Abstract
Steel plate shear walls (SPSWs) have shown a desirable performance in experimental studies and past earthquakes. The advantages of the SPSW and its good performance against lateral loads persuade designers to utilize the system in their practical projects. Some important aspects of the SPSW have remained unknown in spite of valuable experimental and numerical studies. One of these unknown characteristics is the effect of cracks on the SPSW behavior. Several experimental studies have reported fracture in SPSW due to crack propagation during testing, but the experimental studies have not investigated the crack effect. Due to low thickness of steel plate and inherence of crack, the crack...
A combined experimental and numerical study of the effect of surface roughness on nanoindentation
, Article International Journal of Applied Mechanics ; Volume 11, Issue 7 , 2019 ; 17588251 (ISSN) ; Chamani, M ; Baghani, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2019
Abstract
Gold and copper thin films are widely used in microelectromechanical system (MEMS) and nanoelectromechanical system (NEMS) devices. Nanoindentation has been developed in mechanical characterization of thin films in recent years. Several researchers have examined the effect of surface roughness on nanoindentation results. It is proved that the surface roughness has great importance in nanoindentation of thin films. In this paper, the surface topography of thin films is simulated using the extracted data from the atomic force microscopy (AFM) images. Nanoindentation on a rough surface is simulated using a three-dimensional finite-element model. The results are compared with the results of...
Impact of trim on added resistance of KRISO container ship (KCS) in head waves: An experimental and numerical study
, Article Ocean Engineering ; Volume 211 , 2020 ; Khorasanchi, M ; Day, S ; Turan, O ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this study, added resistance and motion responses of KRISO Container Ship (KCS) were evaluated experimentally and numerically in six different trim angles. A series of towing tank experiments were performed for six different trim angles at design speed in calm water and regular head waves. The ship motions and added resistance were measured for several wavelength conditions considering short and long wave ranges with wave steepness of 1/60. Next, computations of the towed model in calm water and waves were performed using Unsteady Reynolds-Averaged Navier-Stokes (URANS) CFD and 3-D potential methods. Effects of trim angles on added resistance were analysed and results concerning the...