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Experimental investigation of Reynolds stress complex eddy viscosity model for coherent structure dynamics 被引量:9
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作者 JIA YongXia TANG ZhanQi JIANG Nan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第7期1319-1327,共9页
Time sequence signals of streamwise and normal velocity components,as well as velocity strain rate,at different vertical locations in the turbulent boundary layer over a smooth flat plate in a wind tunnel have been fi... Time sequence signals of streamwise and normal velocity components,as well as velocity strain rate,at different vertical locations in the turbulent boundary layer over a smooth flat plate in a wind tunnel have been finely examined by the use of double-sensor hot-wire anemometry.The local module maximum for wavelet coefficient of longitudinal velocity component,as a detecting index,is employed to educe the ejection and sweep process of the coherent structure burst in the turbulent boundary layer from the random fluctuating background.The coherent waveforms of Reynolds stress residual contribution term for random fluctuations to coherent structure,as well as the velocity strain rate of coherent structure,are extracted by the conditional phase average technique.Based on the theoretical analysis of eddy viscosity coefficient in complex eddy viscosity model for coherent structure,the macro-relaxation effect between Reynolds stress residual contribution term of random fluctuations to coherent structure and the velocity strain rate of coherent structure is studied and the variations of the phase difference between them across the turbulent boundary layer are investigated experimentally.The rationality of complex eddy viscosity model for coherent structure is confirmed through the investigation. 展开更多
关键词 turbulent boundary layer coherent structure complex eddy viscosity model Reynolds stress phase difference
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Effect of the size and pressure on the modified viscosity of water in microchannels 被引量:6
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作者 Zhao-Miao Liu Yan Pang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第1期45-52,共8页
The phenomenon that flow resistances are higher in micro scale flow than in normal flow is clarified through the liquid viscosity. Based on the experimental results of deionized water flow in fused silica microtubes w... The phenomenon that flow resistances are higher in micro scale flow than in normal flow is clarified through the liquid viscosity. Based on the experimental results of deionized water flow in fused silica microtubes with the in- ner radii of 2.5 μm, 5μm, 7.5μm, and 10 μm, respectively, the relationship between water flow velocity and pressure gradient along the axis of tube is analyzed, which gradually becomes nonlinear as the radius of the microtube decreases. From the correlation, a viscosity model of water flow derived from the radius of microtube and the pressure gradient is pro- posed. The flow results modified by the viscosity model are in accordance with those of experiments, which are verified by numerical simulation software and the Hagen-Poiseuille equation. The experimental water flow velocity in a fused silica microtube with diameter of 5.03 μm, which has not been used in the fitting and derivation of the viscosity model, is proved to be comsistent with the viscosity model, showing a rather good match with a relative difference of 5.56%. 展开更多
关键词 MICROTUBE viscosity model Pressure gradientHagen-Poiseulle equation
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Rheological Behavior and Process Prediction of Low Viscosity Epoxy Resin for RTM 被引量:2
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作者 周洲 蒋炳炎 +2 位作者 CHEN Xingkai JIANG Fengze JIAN Yuping 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第5期1078-1082,共5页
The rheological behavior of a low epoxy resin system-SR8100/SD8734 for RTM in aviation industry was studied with viscosity experiments. The dual-Arrhenius rheological model and the improved engineering viscosity model... The rheological behavior of a low epoxy resin system-SR8100/SD8734 for RTM in aviation industry was studied with viscosity experiments. The dual-Arrhenius rheological model and the improved engineering viscosity model were introduced and compared with the experimental data. The results indicated that the viscosity in the earlier stage calculated by dual-Arrhenius model matched the experimental data. As rising to 400 m.Pas, the viscosity calculated by the improved engineering model was closer to the experimental data. The processing windows of the resin system for RTM were determined by combining the two models, which could predict the theological behavior of the resin system in a more credible way. 30-45 ℃ was the optimum processing temperature. 展开更多
关键词 resin transfer molding(RTM) rheological behavior epoxy resin system viscosity model
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Nonlinear turbulence models for predicting strong curvature effects
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作者 徐晶磊 马晖扬 黄宇宁 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第1期31-42,共12页
Prediction of the characteristics of turbulent flows with strong streamline curvature, such as flows in turbomachines, curved channel flows, flows around airfoils and buildings, is of great importance in engineering a... Prediction of the characteristics of turbulent flows with strong streamline curvature, such as flows in turbomachines, curved channel flows, flows around airfoils and buildings, is of great importance in engineering applications and poses a very practical challenge for turbulence modeling. In this paper, we analyze qualitatively the curvature effects on the structure of turbulence and conduct numerical simulations of a turbulent Uduct flow with a number of turbulence models in order to assess their overall performance. The models evaluated in this work are some typical linear eddy viscosity turbulence models, nonlinear eddy viscosity turbulence models (NLEVM) (quadratic and cubic), a quadratic explicit algebraic stress model (EASM) and a Reynolds stress model (RSM) developed based on the second-moment closure. Our numerical results show that a cubic NLEVM that performs considerably well in other benchmark turbulent flows, such as the Craft, Launder and Suga model and the Huang and Ma model, is able to capture the major features of the highly curved turbulent U-duct flow, including the damping of turbulence near the convex wall, the enhancement of turbulence near the concave wall, and the subsequent turbulent flow separation. The predictions of the cubic models are quite close to that of the RSM, in relatively good agreement with the experimental data, which suggests that these models may be employed to simulate the turbulent curved flows in engineering applications. 展开更多
关键词 curvature effect nonlinear eddy viscosity turbulence model Reynolds stressmodel
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Two dimensional analytical solution for a partially vegetated compound channel flow 被引量:5
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作者 槐文信 徐治钢 +1 位作者 杨中华 曾玉红 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第8期1077-1084,共8页
The theory of an eddy viscosity model is applied to the study of the flow in a compound channel which is partially vegetated. The governing equation is constituted by analyzing the longitudinal forces acting on the un... The theory of an eddy viscosity model is applied to the study of the flow in a compound channel which is partially vegetated. The governing equation is constituted by analyzing the longitudinal forces acting on the unit volume where the effect of the vegetation on the flow is considered as a drag force item, The compound channel is divided into 3 sub-regions in the transverse direction, and the coefficients in every region's differential equations were solved simultaneously. Thus, the analytical solution of the transverse distribution of the depth-averaged velocity for uniform flow in a partially vegetated compound channel was obtained. The results can be used to predict the transverse distribution of bed shear stress, which has an important effect on the transportation of sediment. By comparing the analytical results with the measured data, the analytical solution in this paper is shown to be sufficiently accurate to predict most hydraulic features for engineering design purposes. 展开更多
关键词 compound channel depth-averaged velocity drag force eddy viscosity model analytical solution VEGETATION
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Rheological Behaviors of Fresh Cement Pastes with Polycarboxylate Superplasticizer 被引量:6
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作者 张艳荣 孔祥明 +1 位作者 高亮 WANG Jiaxin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第2期286-299,共14页
The rheologicalbehaviors of fresh cement paste with polycarboxylate superplasticizer were systematically investigated.Influentialfactors including superplasticizer to cement ratio(Sp/C),water to cement ratio(w/c),... The rheologicalbehaviors of fresh cement paste with polycarboxylate superplasticizer were systematically investigated.Influentialfactors including superplasticizer to cement ratio(Sp/C),water to cement ratio(w/c),temperature,and time were discussed.Fresh cement pastes with Sp/Cs in the range of 0 to 2.0% and varied W/Cs from 0.25 to 0.5 were prepared and tested at 0,20 and 40 °C,respectively.Flowability and rheologicaltests on cement pastes were conducted to characterize the development of the rheologicalbehavior of fresh cement pastes over time.The exprimentalresults indicate that the initialflowability and flowability retention over shelf time increase with the growth in superplasticizer dosage due to the plasticizing effect and retardation effect of superplasticizer.Higher temperature usually leads to a sharper drop in initialflowability and flowability retention.However,for the cement paste with high Sp/C or w/c,the flowability is slightly affected by temperature.Yield stress and plastic viscosity show similar variation trends to the flowability under the abovementioned influentialfactors at low Sp/C.In the case of high Sp/C,yield stress and plastic viscosity start to decline over shelf time and the decreasing rate descends at elevated temperature.Moreover,two equations to roughly predict yield stress and plastic viscosity of the fresh cement pastes incorporating Sp/C,w/c,temperature and time are developed on the basis of the existing models,in which experimentalconstants can be extracted from a database created by the rheologicaltest results. 展开更多
关键词 cement paste flowability yield stress plastic viscosity model
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THE INVESTIGATION ON THE RHEOLOGICAL BEHAVIOR OF SEMI-SOLID ALUMINUM ALLOY DURING DIE CASTING 被引量:1
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作者 X.J. Yang and J.Liu School of Mechanic & Electronic Engineering, Nanchang University, Jiangxi 330029, China School of Mechanic & Electronic Engineering, Shanghai University, Shanghai 200072, China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2002年第6期511-516,共6页
Under the condition of die casting and reheating temperature of 570-580 degC, the rheological behavior of semi-solid aluminum alloy (A356) is pseudoplasticity at the shearrate of 2X10^-1X10^4s^(-1), and also shows dil... Under the condition of die casting and reheating temperature of 570-580 degC, the rheological behavior of semi-solid aluminum alloy (A356) is pseudoplasticity at the shearrate of 2X10^-1X10^4s^(-1), and also shows dilatancy at the rate over 10~6s^(-1). 展开更多
关键词 shear rate apparent viscosity viscosity model THIXOCASTING
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Multi-model coupling-based dynamic control system of ladle slag in argon blowing refining process 被引量:2
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作者 Guang-da Bao Ting Wu +2 位作者 Duo-gang Wang Xiao-bin Zhou Hai-chuan Wang 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2023年第5期926-936,共11页
Since the current slagging of argon blowing refining process is relatively fixed,which cannot adapt to the fluctuation of converter smelting process,it poses the problems of poor metallurgical property of refining sla... Since the current slagging of argon blowing refining process is relatively fixed,which cannot adapt to the fluctuation of converter smelting process,it poses the problems of poor metallurgical property of refining slag and a large amount of molten heel.An optimization system coupled with multiple models was proposed to dynamic control the ladle slagging in the argon blowing refining process.It can compile the optimal dynamic slagging scheme in real time under the guarantee of deoxidation performance and reasonable fluidity.The argon blowing refining slag composition range of CaO/Al_(2)O_(3)=1.3-1.7,CaO/SiO_(2)=6-12,w(MgO)=2%-6% was determined based on FeO activity and liquidus temperature by equilibrium thermodynamic calculation.In addition,it demonstrated better performance in the viscosity prediction task of the presented Visual Geometry Group 16-like one-dimensional convolutional neural network deep learning algorithm versus the Random Forest ensemble learning algorithm,as the adjusted coefficients of determination were 0.9712 and 0.9637,respectively.After the system was applied in operation,the argon blowing refining process was stable,and the steel yield was enhanced,which promoted the intelligent steelmaking level while achieving the cost reduction and efficiency improvement. 展开更多
关键词 Argon blowing refining process DEOXIDATION viscosity model Deep learning Intelligent steelmaking
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CHEMORHEOLOGY OF MODIFIED BISMALEINIDE RESIN SYSTEM
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作者 王伟 黄志雄 周祖福 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1996年第1期6-11,共6页
The chemorheology of bismaleimide (BMI) resin system comprised of 4,4'-bismaleimidodiphenyl-methane, 4,4'-diaminodiphenyl-methane, phenoltype epoxy resin, and carboxyl-terminated butadiene-acrylonitrile rubber... The chemorheology of bismaleimide (BMI) resin system comprised of 4,4'-bismaleimidodiphenyl-methane, 4,4'-diaminodiphenyl-methane, phenoltype epoxy resin, and carboxyl-terminated butadiene-acrylonitrile rubber was investigated. Thermal analysis techniques were employed to obtain Kinetic and network parameters which is necessary for the development of a phenomenological viscosity model based on a modified version of the Wiliams-Landel-Ferry (WLF) equation. The model predictions agreed well with experimental value of viscosity. 展开更多
关键词 BISMALEIMIDE CHEMORHEOLOGY kinetic parameters williams-Landel-Ferry (WLF) equation phenomenological viscosity model
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Conditions and Phase Shift of Fluid Resonance in Narrow Gaps of Bottom Mounted Caissons
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作者 ZHU Da-tong WANG Xing-gang LIU Qing-jun 《China Ocean Engineering》 SCIE EI CSCD 2017年第6期724-735,共12页
This paper studies the viscid and inviscid fluid resonance in gaps of bottom mounted caissons onthe basis of the plane wave hypothesis and full wave model, The theoretical analysis and the numerical results demonstrat... This paper studies the viscid and inviscid fluid resonance in gaps of bottom mounted caissons onthe basis of the plane wave hypothesis and full wave model, The theoretical analysis and the numerical results demonstrate that the condition for the appearance of fluid resonance in narrow gaps is kh=(2n+1)π (n=0, 1, 2, 3 ), rather than kh=nn (n=0, 1, 2, 3, ...); the transmission peaks in viscid fluid are related to the resonance peaks in the gaps. k and h stand for the wave number and the gap length. The combination of the plane wave hypothesis or the full wave model with the local viscosity model can accurately determine the heights and the locations of the resonance peaks. The upper bound for the appearance of fluid resonance in gaps is 2b/L〈l (2b, grating constant; L, wave length) and the lower bound is h/b〈~ l. The main reason for the phase shift of the resonance peaks is the inductive factors. The number of resonance peaks in the spectrum curve is dependent on the ratio of the gap length to the grating constant. The heights and the positions of the resonance peaks predicted by the present models agree well with the experimental data. 展开更多
关键词 gap resonance phase shift of resonance peak fluid local viscosity model plane wave hypothesis full wavemodel bottom mounted caissons
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Viscosity prediction on iron-bearing slags during pyrometallurgical recycling: structure-based modeling of CaO-‘FeO’-MgO-Al_(2)O_(3)-SiO_(2) system and its subsystems
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作者 Guang-zong Zhang Nan Wang +1 位作者 Min Chen Yan-qing Cheng 《Journal of Iron and Steel Research International》 SCIE EI CSCD 2021年第6期679-692,共14页
A structure-based modeling of the CaO-‘FeO’-MgO-Al_(2)O_(3)-SiO_(2) system and its subsystems was investigated based on iron extraction nickel slagaluminum dross.Parameters optimization in the present model indicate... A structure-based modeling of the CaO-‘FeO’-MgO-Al_(2)O_(3)-SiO_(2) system and its subsystems was investigated based on iron extraction nickel slagaluminum dross.Parameters optimization in the present model indicated that the coefficient of free O^(2-)in FeO,a_(O_(FeO)^(2-)),on the lengths of network linkage had the largest value and O_(FeO)^(2-)(free O^(2)-in FeO)had the largest mobility.The coefficients of bridging oxygen(a_(Si-O-Al) and a_(Al-O-Al))were lower than those of nonbridging oxygen and free oxygen(O^(2-)).Viscosity prediction for the CaO-‘FeO’-(8 wt.%)MgO-Al_(2)O_(3)-SiO_(2) system was conducted at a fixed slag basicity,which indicated that the predicted viscosity changed monotonously with the FeO content.However,the non-monotonous evolution with Al2O3 content reflected the amphoteric behavior of Al2O3.In addition,the performances of the present model in predicting viscosity binary(‘FeO’-SiO_(2))to quinary(CaO-‘FeO’-MgO-Al_(2)O_(3)-SiO_(2))system were analyzed and a comparison with the established models was made. 展开更多
关键词 Nickel slag viscosity model Slag structure Iron-bearing slag CaO-FeO-MgO-Al_(2)O_(3)-SiO_(2)system
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Wall Sticking of High Water-Cut, Highly Viscous and High Gel-Point Crude Oil Transported at Low Temperatures 被引量:20
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作者 Zheng Haimin Huang Qiyu +1 位作者 Wang Changhui Wang Xi 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2015年第4期20-29,共10页
Some crude oils with high water cut have the capability to flow below the oil gel point, while the oil particles adhere to the pipe wall in the form of paste, also called "wall sticking". Wall sticking is a ... Some crude oils with high water cut have the capability to flow below the oil gel point, while the oil particles adhere to the pipe wall in the form of paste, also called "wall sticking". Wall sticking is a serious problem during the pipeline transportation, leading to partial or total blockage of the pipeline and energy wastage. In this paper, a series of laboratory flow loop experiments were conducted to observe the wall sticking characteristics of crude oil with high water cut, high viscosity and high gel point at low transportation temperatures. The effects of shear stress and water cut on the wall sticking rate and occurrence temperature were investigated. Experimental results indicated that the wall sticking rate and occurrence temperature were lower under stronger shear stress and higher water cut conditions. A criterion of wall sticking occurrence temperature(WSOT) and a regression model of wall sticking rate were then established. Finally, the software was developed to calculate the pressure drop along the pipelines of crude oils with high water-cut. It was able to predict the wall sticking thickness of gelled oil and then calculate the pressure drop along the pipelines. A typical case study indicated that the prediction results obtained from the software were in agreement with actual measured values. 展开更多
关键词 wall sticking high viscosity high water cut flow loop regression model
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Calculation of tip vortex cavitation flows around three-dimensional hydrofoils and propellers using a nonlinear k-ε turbulence model 被引量:15
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作者 刘志辉 王本龙 +1 位作者 彭晓星 刘登成 《Journal of Hydrodynamics》 SCIE EI CSCD 2016年第2期227-237,共11页
Simulations of tip vortex wetted flows and cavitating flows are carried out by using a RANS model. Two types of turbule- nce models, with and without the Boussinesq turbulent-viscosity hypothesis, are adopted in compa... Simulations of tip vortex wetted flows and cavitating flows are carried out by using a RANS model. Two types of turbule- nce models, with and without the Boussinesq turbulent-viscosity hypothesis, are adopted in comparing with experimental results regarding the vorticity, the strain rate and the Reynolds shear stress distributions in the vortex region. The numerical results imply that the spatial phase shift between the mean strain rate and the Reynolds stresses can be accurately modeled by the nonlinear κ-ε turbulence model, the tip vortex cavitation region can only be predicted using the nonlinear κ-ε turbulence model. The mecha- nism of the over-dissipation due to the turbulence model is analyzed in terms of the turbulence production, which is one of the dominant source terms in the transport equations of energy. 展开更多
关键词 tip vortex tip vortex cavitation Boussinesq turbulence viscosity model nonlinear turbulence model OPENFOAM
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A NEW STABILIZED SUBGRID EDDY VISCOSITY METHOD BASED ON PRESSURE PROJECTION AND EXTRAPOLATED TRAPEZOIDAL RULE FOR THE TRANSIENT NAVIER-STOKES EQUATIONS 被引量:8
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作者 Minfu Feng Yanhong Bai +1 位作者 Yinnian He Yanmei Qin 《Journal of Computational Mathematics》 SCIE CSCD 2011年第4期415-440,共26页
We consider a new subgrid eddy viscosity method based on pressure projection and extrapolated trapezoidal rule for the transient Navier-Stokes equations by using lowest equal-order pair of finite elements. The scheme ... We consider a new subgrid eddy viscosity method based on pressure projection and extrapolated trapezoidal rule for the transient Navier-Stokes equations by using lowest equal-order pair of finite elements. The scheme stabilizes convection dominated problems and ameliorates the restrictive inf-sup compatibility stability. It has some attractive fea- tures including parameter free for the pressure stabilized term and calculations required for higher order derivatives. Moreover, it requires only the solutions of the linear system arising from an Oseen problem per time step and has second order temporal accuracy. The method achieves optimal accuracy with respect to solution regularity. 展开更多
关键词 Subgrid eddy viscosity model Pressure projection method Extrapolated trape-zoidal rule The transient Navier-Stokes equations.
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Discrete and continuum modeling of granular flow in silo discharge 被引量:6
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作者 Tian Tian Jinglin Su +3 位作者 Jinhui Zhan Shujun Geng Guangwen Xu Xiaoxing Liu 《Particuology》 SCIE EI CAS CSCD 2018年第1期127-138,共12页
Granular material discharge from a flat-bottomed silo has been simulated by using continuum modeling and a three-dimensional discrete-element method (DEM). The predictive abilities of three commonly used frictional ... Granular material discharge from a flat-bottomed silo has been simulated by using continuum modeling and a three-dimensional discrete-element method (DEM). The predictive abilities of three commonly used frictional viscosity models (Schaeffer, S-S, and μ(I)) were evaluated by comparing them with the DEM data. The funnel-flow pattern (type C) and the semi-mass-flow pattern (type B) that was predicted by DEM simulations can be represented when the Schaeffer orμ(I) model is used, whereas the S-S model gives a consistent type-B flow pattern. All three models over-estimate the discharge rate compared with the DEM. The profiles of the solids volume fraction and the vertical velocity above the outlet show that the larger discharge rates given by the Schaeffer and μ(I) model result from an over-estimation of volume fraction, whereas the deviation in the S-S model stems from the failure to predict a solid vertical velocity and a volume fraction. 展开更多
关键词 SILO Flow pattern Discharge rate Discrete-element model Frictional viscosity model
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An hybrid RANS/LES model for simulation of complex turbulent flow
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作者 魏群 陈红勋 马峥 《Journal of Hydrodynamics》 SCIE EI CSCD 2016年第5期811-820,共10页
A nonqinear eddy viscosity model (NLEVM) and a scalable hybrid Reynolds averaged Navier-Stokes/large eddy simula- tion (RANS/LES) strategy are developed to improve the capability of the eddy viscosity model (EVM... A nonqinear eddy viscosity model (NLEVM) and a scalable hybrid Reynolds averaged Navier-Stokes/large eddy simula- tion (RANS/LES) strategy are developed to improve the capability of the eddy viscosity model (EVM) to simulate complex flows featuring separations and unsteady motions. To study the performance of the NLEVM, numerical simulations around S809 airfoil are carried out and the results show that the NLEVM performs much better when a large separation occurs. Calculated results of the flow around a triangular cylinder show that the NLEVM can improve the precision of the flow fields to some extents, but the error is still considerable, and the small turbulence structures can not be clearly captured as the EVM. Whereas the scalable hybrid RANS/LES model based on the NLEVM is fairy effective on resolving the turbulent structures and can give more satisfactory predictions of the flow fields. 展开更多
关键词 turbulence model non-linear eddy viscosity model (NLEVM) hybrid Reynolds averaged Navier-Stokes/large eddysimulation (RANS/LES)
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Numerical simulation on flow of ice slurry in horizontal straight tube
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作者 Shengchun LIU Ming SONG +1 位作者 Ling HAO Pengxiao WANG 《Frontiers in Energy》 SCIE CSCD 2021年第1期201-207,共7页
Numerical simulation on flow of ice slurry in horizontal straight tubes was conducted in this paper to improve its transportation characteristics and application.This paper determined the influence of the diameter and... Numerical simulation on flow of ice slurry in horizontal straight tubes was conducted in this paper to improve its transportation characteristics and application.This paper determined the influence of the diameter and length of tubes,the ice packing factors(IPF)and the flow velocity of ice slurry on pressure loss by using numerical simulation,based on two-phase flow and the granular dynamic theory.Furthermore,it was found that the deviation between the simulation results and experimental data could be reduced from 20%to 5%by adjusting the viscosity which was reflected by velocity.This confirmed the reliability of the simulation model.Thus,two mathematical correlations between viscosity and flow velocity were developed eventually.It could also be concluded that future rheological model of ice slurry should be considered in three sections clarified by the flow velocity,which determined the fundamental difference from single-phase fluid. 展开更多
关键词 ice slurry horizontal tubes numerical simulation pressure drop viscosity model
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Computational Studies of Lobed Forced Mixer Flows
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作者 H.Hu S.C.M.Yu 《Journal of Thermal Science》 SCIE EI CAS CSCD 1998年第1期22-28,共7页
Full Navier-Stokes Analyses have been conducted for the flows behind the trailing edge of a lobed forced mixer. The governing equations are derived from the timedependent compressible Navier-Stokes equa tions and disc... Full Navier-Stokes Analyses have been conducted for the flows behind the trailing edge of a lobed forced mixer. The governing equations are derived from the timedependent compressible Navier-Stokes equa tions and discretized in the finite-difference form. A simple two-layer eddy viscosity model has also been used to account for the turbulence. Computed results are compared with some of the velocity measurements using a laserDoppler anemometer (Yu and Yip (1997)). In general, good agreement can be obtained in the streamwise mean velocity distribution but the decay of the streamwise circulation is underpredicted. Some suggestions to the discrepancy are proposed. 展开更多
关键词 lobed forced mixer flows eddy viscosity model velocity distribution
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A comprehensive physical insight about thermo physical aspects of Carreau fluid flow over a rotated disk of variable thickness by implementing finite difference approach
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作者 Sardar Bilal Imtiaz Ali Shah 《Propulsion and Power Research》 SCIE 2022年第1期143-153,共11页
Present communication is devoted to analyze thermal characteristics of Carreau liquid flowing on variably thickened non-uniformly rotating disk.Mathematical formulation is constructed in view of complex coupled partia... Present communication is devoted to analyze thermal characteristics of Carreau liquid flowing on variably thickened non-uniformly rotating disk.Mathematical formulation is constructed in view of complex coupled partial differential system.Afterwards,boundary layer approach is executed for comprehensive examination of under consideration phenomenon with in boundary layer region.Karman’s transformation is capitalized to convert the attained PDE’s into ordinary differential equations system.Solution of attained ODE’s system is solved numerically by implementing Keller-Box scheme.Influence of protuberant involved parameters on momentum and thermal distributions is illustrated through sketches.In addition,impact of flow concerning parameters on wall shear stress and thermal flux is also evaluated.The assurance of present finding is done by making agreement with published results and by restricting considered problem to Newtonian case.Here,we observed that radially and tangentially directed wall drag lessen with growing magnitude of power law exponent index.Moreover,the consequence of disk thickness parameter grows stresses along radial direction whereas opposite behavior is depicted in case of tangentially directed friction and heat flux factors. 展开更多
关键词 Carreau viscosity model Rotating disk Non-uniform thickness Keller-Box method
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