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مرکز اطلاعات علمی SID1
اسکوپوس
مرکز اطلاعات علمی SID
ریسرچگیت
strs
Author(s): 

AHMADI B. | SAZEGAR H.

Issue Info: 
  • Year: 

    2017
  • Volume: 

    7
  • Issue: 

    3
  • Pages: 

    344-352
Measures: 
  • Citations: 

    0
  • Views: 

    905
  • Downloads: 

    332
Abstract: 

Background & Objective: Inflammation is an undesirable condition resulted from the effect of Arachidonic Acid metabolites especially prostaglandins. With regard to the side-effects of chemical anti-inflammatory medicines, this study was done aiming at examining the effect of 3D music on the extent of inflammation.Materials & Methods: In this experimental study, 20 male Wistar rats (200-250 g) were randomly divided into 4 groups of 5 each, including healthy control group, inflammatory control group, inflammatory recipient of 50 ml of carrageenan1%, treated inflammatory with 2 mg per kg body weight dexamethasone and treated inflammatory with Three-dimensional music player (8h). Finally, CRP blood test and weight difference between the injected right foot and the left foot were measured. One-way analysis of variance (ANOVA) was used to analyze the data through SPSS software.There was a significant mean difference between groups, using Tukey test at (p<0.05).Results: CRP levels in treated groups by dexamethasone (10.6±3.24mg/l), and music (16±9.95mg/l), compared to the control group (37.8±5.24mg/l), were significantly decreased, which this decrease was more discernable in treated groups that received dexamethasone. The weight difference between the left and right foot in the treatment group (0.016±0.007g), (0.044±0.044g) compared to the control group (0.154±0.056g), was significantly decreased.Conclusion: Dexamethasone can remove inflammation and Three-dimensional music can reduce inflammation less than dexamethasone in the inflammatory animals.

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Issue Info: 
  • Year: 

    2000
  • Volume: 

    12
  • Issue: 

    1
  • Pages: 

    13-28
Measures: 
  • Citations: 

    0
  • Views: 

    907
  • Downloads: 

    119
Abstract: 

The main purpose of this paper is to study numerically the flow-field of an incompressible viscous flow in a curved pipe (1800) with two straight pipes attached to both ends. In order to extend the capabilities of the finite volume method, a boundary (body) fitted coordinate (BFC) method is used. Transformation of the partial differential equations to algebraic relations is based on the finite-volume method with collocated variables arrangement. For solving the obtained algebraic relations the TDMA in periodic state is used. To approximate the convective. fluxes, the differencing scheme of Van Leer is used and SIMPLEC handles the linkage between velocities and pressures. For verification of the code, a test case of flow in a (1800) curved pipe at Reynolds number of 242 is performed and the good agreement between the present results with the numerical and experimental data is obtained. This study showed that by adding two straight pipes at the ends of a curved (1800) pipe, the strength of the secondary flow in the curved zone is reduced.  

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Issue Info: 
  • Year: 

    2019
  • Volume: 

    20
  • Issue: 

    75
  • Pages: 

    101-116
Measures: 
  • Citations: 

    0
  • Views: 

    243
  • Downloads: 

    137
Abstract: 

Intake Modules are structures that deliver relatively constant discharge irrespective of water surface fluctuations. One of these modules is baffle sluice modules for which various theoretical methods have been proposed so far for determining their dimensions. Determining the best theoretical approach requires experimental studies. In this regard experimentations have been carried out only for low capacities. Therefore, numerical methods can be used to identify design criteria of baffle modules in higher capacities. But because of the scale effect on experimental models such as weir, the use of these models in higher capacities requires time and cost. Also, considering the type of design of the baffle modules, determination of the sensitivity of baffle height in determining the share of flow over the baffles and the rate of discharge of each duct is very important, which is not feasible in Experimental models. In this research aims to evaluate the application of Three-dimensional numerical models in simulation of flow in baffle modules for reproduction of observational data, determination of the share of flow over the baffles, the rate of discharge of each parallel duct and the use of stage-discharge equations. The result of flow-3D software indicated that very good concurrence exists between the numerical model output and the observed data for low discharge and this software is applicable to determination of design criteria for the modules for high capacities, determination of the share of flow over the baffles, the rate of discharge of each parallel duct and the use of stage-discharge equations. This indicated the capability of such mean to substitute experimental test or to decrease their use for special cases with an average error of about 1. 7% for 14 l/s, 3. 97% for 10 l/s, 5. 22% for 7 l/s and 7. 94% for 4 l/s.

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گارگاه ها آموزشی
Author(s): 

DIKBAS F.

Journal: 

SCIENTIA IRANICA

Issue Info: 
  • Year: 

    2016
  • Volume: 

    23
  • Issue: 

    1 (TRANSACTIONS A: CIVIL ENGINEERING)
  • Pages: 

    45-53
Measures: 
  • Citations: 

    0
  • Views: 

    47869
  • Downloads: 

    33110
Abstract: 

Imputation of missing data is a critical part of accurate data analysis and modeling. This paper presents 3D imputation as a new data-driven methodology to estimate missing values in time series data. The method is based on the assumption that all the observed data in a time series are related with each other and with data of the some other series. The available data is placed in a Three-dimensional space so that the increasing or decreasing relationships between the observed data are appropriately represented. For the estimation of each missing value, the method searches and determines the best possible group of estimator data within the data space. Di erent data groups are found and used for the estimations of each individual group of missing data. The method is validated by removing and estimating all the observed monthly flow data of Saraykoy station on Buyuk Menderes River in Turkey. Data of the downstream Burhaniye station constituted the second data layer in the model. High correlation values were obtained for all years between observations and estimations and the missing data of Saraykoy station was also estimated by using the proposed method.

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Issue Info: 
  • Year: 

    2020
  • Volume: 

    6
  • Issue: 

    3
  • Pages: 

    531-542
Measures: 
  • Citations: 

    0
  • Views: 

    31381
  • Downloads: 

    36905
Abstract: 

This study presents the computational analysis of Three dimensional Casson and Carreau nanofluid flow concerning the convective conditions. To do so, the flow equations are modified to nonlinear system of ODEs after using appropriate self-similarity functions. The solution for the modified system is evaluated by numerical techniques. The results show the impacts of involving variables on flow characteristics and the outcomes of the friction factors are evaluated as well. In this study, the outcomes to local Nusselt number and Sherwood numbers are evaluated. Favourable comparison is performed with previously available outcomes. The achieved results are similar to solutions obtained by other researchers. The results are presented for flow characteristics in the case of Casson and Carreau fluids. Velocities are reduced for the growing values of permeability and velocity slip parameters in case of Casson and Carreau nanofluids. Temperature field enhances with the hike in the estimations of thermophoresis parameter and the thermal Biot number in case of Casson and Carreau nanofluids. Enhancing values of velocity slip parameter results in decrease in the skin friction coefficients and the rate of heat transfer, and rise in the rate of mass transfer in case of Casson and Carreau nanofluids.

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Issue Info: 
  • Year: 

    2002
  • Volume: 

    27
  • Issue: 

    27
  • Pages: 

    57-65
Measures: 
  • Citations: 

    0
  • Views: 

    1070
  • Downloads: 

    290
Abstract: 

Francis turbines are one of the most popular turbines used in hydraulic power plants. In this paper, several relations are introduced to determine the approximate shape of the turbine runner and then the fluid flows inside the runner as well as the draft tube are numerically simulated. First, an approximate shape for the runner passage (i.e. hub and shroud profiles) is determined which is based on experimental data and then using the provided data for H, Q and N the runner blades are designed. flow simulations are based on the 3D Solution of the Navier-Stokes equations for incompressible turbulent flows. A commercially a vailable CDF code is used for the numerical simulation. The numerical results for flows inside the turbine runner and the tube indicate the capability of the code for such flow simulations and show that such utilities could be used to numerically investigate complicated phenomena such as cavitation and separation inside turbomachines. In addition, these CFD codes could be used in shape optimization for turbine blades.

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strs
Journal: 

JOURNAL OF HYDRAULICS

Issue Info: 
  • Year: 

    2022
  • Volume: 

    17
  • Issue: 

    2
  • Pages: 

    71-86
Measures: 
  • Citations: 

    0
  • Views: 

    56
  • Downloads: 

    128
Abstract: 

Introduction: Channel bends are sometimes unavoidable due to the project conditions or the land topography. However, oblique cross waves are a distinct feature of supercritical flow in bends. These waves continue for a long distance downstream and increase the height of water considerably. Initially, the complex behavior of supercritical flow in bends was studied by hydraulic models in a laboratory. Later on, numerical models were found inexpensive tools to investigate flow patterns and explain features that may not even be possible to measure. In this article, supercritical flow in a rectangular horizontal channel of 90º bend is studied with different ratios of radius to channel width (rc/b) using two-and Threedimensional numerical models. Water surface profiles are then compared with the data that were obtained from our experimental bend models. It is proved that Three-dimensional models are more successful in predicting the flow profile, peak, and location of waves at the outer wall bend. Methodology: In this study, flow3D package was used for the Three-dimensional simulation of flow patterns. This software had a wide variety of applications and capabilities. The user could enter information to select different models to provide a range of flow phenomena. flow3D integrated the Navier-Stokes equations (N-S) with finite volume method (FVM), with different mesh configurations, suitable for complex geometries. The k-ε turbulence model was used to close the N-S partial differential equations. The volume of fluid (VOF) method was used to model the free surface boundary. Additional boundary conditions for supercritical flow in bends was selected as constant depth and velocity at the inflow section and no-slip or zero velocity conditions at the floor and solid walls. The Roe2D model was used for the simulation of two-dimensional shallow water equations. This model was able to capture discontinuities such as shock waves in supercritical flow. A triangular mesh was used for the space discretization, and a minmod slope limiter was implemented to control oscillations. Experiments were performed in the curved channel of the hydraulic laboratory of Ferdowsi University of Mashhad. This rectangular channel was horizontal, 40 cm in width, and the walls and floor were made of transparent plexiglass sheets. A straight channel, 1. 8 m length, was installed before the bend to ensure flow development length. At the end of this channel there was the 90º channel bend with internal and external radii of 40 and 80 cm, respectively. The channel width could be changed by adding interior walls; thereby, the ratio of rc/b might be changed accordingly. Results and Discussion: Several experiments were run in the curved channels with widths of 15, 20, 30, and 40 cm and different radius of curvature to channel width (rc/b). The flow rate and water depth were measured, and thereby the approach Froude number Fro was calculated. New experimental equations were obtained to calculate the maximum flow depth and the location of the first wave crest along the outer wall in the terms of the approach Froud number and the geometric specification of the bend. For each experiment, the corresponding two-and Three-dimensional computer models were performed, too. The Three-dimensional model could properly estimate the behavior of the supercritical flow, including the depth and position of wave crest at the outer wall of the bend. As Fro increased or rc/b decreased, the wave peak increased and moved downstream. However, the twodimensional model had acceptable accuracy only for low values of Fr0 < 3. The assumption of hydrostatic pressure in depth-averaged 2D models was not applicable to supercritical bend flows. For flows with low Fro, the vertical acceleration might be ignored; however, as Fro increased, it became significant within the bend, and its negligence led to large errors in computations. In flows with high Fro, the maximum vertical acceleration occurred at the beginning of the bend (minimum depth point), and the minimum occurred at the wave crest. At high Fro, the vertical acceleration was downward, causing the hydrodynamic pressure to become less than the corresponding hydrostatic pressure. Conclusions: The Three-dimensional model of flow3D is a suitable tool for the simulation of high-velocity supercritical flows in bends in comparison with the two-dimensional depthaveraged model of shallow water equation of Roe2D. By examining the pressure distribution and vertical acceleration in the numerical models, it may be concluded that the basic assumption in the extraction of shallow water equations, namely the hydrostatic pressure distribution, is not admissible, especially at high Froude numbers. Moreover, the effects of vertical acceleration of water particles has a great effect on the estimation of wave crest depth and its position in the bend.

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Issue Info: 
  • Year: 

    2001
  • Volume: 

    11
  • Issue: 

    6
  • Pages: 

    25-34
Measures: 
  • Citations: 

    0
  • Views: 

    788
  • Downloads: 

    119
Abstract: 

The Three dimensional model of metal flow in the mould has been investigated using an electrical device. The results show that the flow pattern can not be repeated in a levelled mould. The flow pattern is highly affected dy the mould angel. This, results in an accurate prevention of metal flow in the mould.

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Issue Info: 
  • Year: 

    2018
  • Volume: 

    11
  • Issue: 

    6
  • Pages: 

    1599-1611
Measures: 
  • Citations: 

    0
  • Views: 

    30135
  • Downloads: 

    36505
Abstract: 

To date, the Smoothed Particle Hydrodynamics (SPH) method has been successfully applied to reproduce the hydrodynamics behind Three-dimensional flow-structure interactions. However, as soon as the effect of flow resistance becomes significant, the results obtained are not consistent with observations. This is the case for open channel flows (OCF), in which the water surface is largely influenced by the boundary friction. The roughness generated by the current boundary condition methodologies is solely numerical and cannot be associated to physical values of friction. In light of this challenge, the authors present a novel formulation for the friction boundary condition. The new implementation includes an additional shear stress at the boundaries to reproduce roughness effects, allowing for the adequate Three-dimensional simulation of open channel flows using the SPH method. Finally, in order to reduce the high computational cost, typical of the Lagrangian models, without interfering in the representativeness of the SPH simulations, a criterion to define the adequate fluid particle size is proposed.

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Issue Info: 
  • Year: 

    2020
  • Volume: 

    6
  • Issue: 

    4
  • Pages: 

    1012-1029
Measures: 
  • Citations: 

    0
  • Views: 

    5906
  • Downloads: 

    5174
Abstract: 

Numerous techniques in designing zones happen at high temperature and functions under high temperature are in a way that involves non-linear radiation. In weakly conducting fluids, however, the currents induced by an external magnetic field alone are too small, and an external electric field must be applied to achieve an efficient flow control. Gailitis and Lielausis, devised Riga plate to generate a crossed electric and magnetic fields which can produce a wall parallel Lorentz force in order to control the fluid flow. It acts as an efficient agent to reduce the skin friction. So, in this paper, we start the numerical investigation on the Threedimensional flow of nanofluids with the inclusion of non-linear radiation past a Riga plate. To this end, the numerical investigation is conducted on the Three-dimensional flow of nanofluids with the inclusion of nonlinear radiation past a Riga plate. Water (H2O) and Sodium Alginate (NaC6H9O7) are the base fluids, whereas Magnetite (Fe3O4) and Aluminium oxide (Al2O3) are the nanoparticles. The mathematical formulation for Sodium Alginate base fluid is separated through the Casson model. Suitable transformations on governing partial differential equations yield strong non-linear ordinary differential equations. Numerical solutions for the renewed system are constructed by fourth-order Runge-Kutta method with shooting technique. Various deductions for flow and heat transfer attributes are sketched and discussed for various physical parameters. Furthermore, the similarities with existing results were found for the physical quantities of interest. It was discovered, that the temperature ratio parameter and the radiation parameter enhance the rate of heat transport. Moreover, the NaC6H9O7-Al2O3 nanofluid improves the heat transfer rate. Likewise, H2O-Fe3O4 nanofluid stimulates the local skin friction coefficients.

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