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Complementary-Label Adversarial Domain Adaptation Fault Diagnosis Network under Time-Varying Rotational Speed and Weakly-Supervised Conditions
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作者 Siyuan Liu Jinying Huang +2 位作者 Jiancheng Ma Licheng Jing Yuxuan Wang 《Computers, Materials & Continua》 SCIE EI 2024年第4期761-777,共17页
Recent research in cross-domain intelligence fault diagnosis of machinery still has some problems,such as relatively ideal speed conditions and sample conditions.In engineering practice,the rotational speed of the mac... Recent research in cross-domain intelligence fault diagnosis of machinery still has some problems,such as relatively ideal speed conditions and sample conditions.In engineering practice,the rotational speed of the machine is often transient and time-varying,which makes the sample annotation increasingly expensive.Meanwhile,the number of samples collected from different health states is often unbalanced.To deal with the above challenges,a complementary-label(CL)adversarial domain adaptation fault diagnosis network(CLADAN)is proposed under time-varying rotational speed and weakly-supervised conditions.In the weakly supervised learning condition,machine prior information is used for sample annotation via cost-friendly complementary label learning.A diagnosticmodel learning strategywith discretized category probabilities is designed to avoidmulti-peak distribution of prediction results.In adversarial training process,we developed virtual adversarial regularization(VAR)strategy,which further enhances the robustness of the model by adding adversarial perturbations in the target domain.Comparative experiments on two case studies validated the superior performance of the proposed method. 展开更多
关键词 Time-varying rotational speed weakly-supervised fault diagnosis domain adaptation
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AN EFFICIENT METHOD FOR SOLVING THE MIXED DIRECT-INVERSE PROBLEM OF THE TRANSONIC ROTATIONAL FLOW IN PLANE CASCADES
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作者 Liu Qiusheng Shen Mengyu Ren Yuxin Qinghua University 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 1989年第4期323-331,共9页
The method in [1] has been extended to the case of rotational flow in this paper. A new method for dealing with the shock wave is presented. This method has the advantages of both the shock-fitting and the shock captu... The method in [1] has been extended to the case of rotational flow in this paper. A new method for dealing with the shock wave is presented. This method has the advantages of both the shock-fitting and the shock capturing methods. The direct problem and the mixed direct-inverse prob- lem of the rotational flow in a transonic plane cascade at both design and off design conditions are solved, and the results show that the present method has rapid convergence rate and high accuracy even for the flow with moderately strong shocks. The calculations have been carried out on the DPS-8 computer, and for the direct problem, only 50-80 iterations are needed, and 50-80 seconds of CPU time are required. 展开更多
关键词 transonic flow cascade flow the rotational flow TURBOMACHINERY the mixed direct-inverse problem.
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Preheating-assisted solid-state friction stir repair of Al-Mg-Si alloy plate at different rotational speeds
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作者 Hui Wang Yidi Li +3 位作者 Ming Zhang Wei Gong Ruilin Lai Yunping Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期725-736,共12页
Additive friction stir deposition(AFSD)is a novel structural repair and manufacturing technology has become a research hotspot at home and abroad in the past five years.In this work,the microstructural evolution and m... Additive friction stir deposition(AFSD)is a novel structural repair and manufacturing technology has become a research hotspot at home and abroad in the past five years.In this work,the microstructural evolution and mechanical performance of the Al-Mg-Si alloy plate repaired by the preheating-assisted AFSD process were investigated.To evaluate the tool rotation speed and substrate preheating for repair quality,the AFSD technique was used to additively repair 5 mm depth blind holes on 6061 aluminum alloy substrates.The results showed that preheat-assisted AFSD repair significantly improved joint bonding and joint strength compared to the control non-preheat substrate condition.Moreover,increasing rotation speed was also beneficial to improve the metallurgical bonding of the interface and avoid volume defects.Under preheating conditions,the UTS and elongation were positively correlated with rotation speed.Under the process parameters of preheated substrate and tool rotation speed of 1000 r/min,defect-free specimens could be obtained accompanied by tensile fracture occurring in the substrate rather than the repaired zone.The UTS and elongation reached the maximum values of 164.2MPa and 13.4%,which are equivalent to 99.4%and 140%of the heated substrate,respectively. 展开更多
关键词 additive friction stir deposition structural repair tool rotation speed Al alloy
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Dual-Fields Rotational Total Skin Electron Therapy: Investigation and Implementation
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作者 M. Ming Xu Iris Rusu Richard P. Garza 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2024年第1期1-15,共15页
Purpose: To present a protocol of a dual-field rotational (DFR) total skin electron therapy (TSET) and to provide an assessment of clinical implementation, dosimetry properties, and skin dose evaluation. Methods and M... Purpose: To present a protocol of a dual-field rotational (DFR) total skin electron therapy (TSET) and to provide an assessment of clinical implementation, dosimetry properties, and skin dose evaluation. Methods and Materials: The DFR-TSET combined the Stanford 6-field and McGill rotational methods. Dual 6 MeV electron beams in high dose total skin electron mode were used for DFR-TSET on a commercial linac. Beam profiles and dosimetric properties were measured using solid phantoms. The dose rate at expanded source-to-surface distance (SSD) was a combination of static rate and rotational rate. In vivo dosimetry of patient skin was performed on patients’ skin using film, metal oxide semiconductor field-effect transistors (MOSFET), and optically stimulated luminescent dosimeters (OSLD). Results: Dual field rotational total skin electron therapy exhibited good (≤±10%) uniformity in the beam profiles in the vertical direction at an extended SSD of 332 cm with a gantry angulation of ±20˚ deviated from the horizontal direction. In-vivo measurements confirmed acceptable uniformity of the patients’ total body surfaces and revealed anatomically self-blocked or shielded areas where underdosing occurred. Conclusions: The clinical implementation of DFR-TSET effectively utilizes the special mode on a linac. This technique provides short beam-on times, uniform dose distribution, large treatment field, and reduced dose of x-ray contamination to the patients. In-vivo measurements indicate satisfactory delivery and dose uniformity of the prescribed dose. Electron boost fields are recommended at normal SSDs to address underdosed areas. 展开更多
关键词 Total Skin Electron Therapy Stanford 6 Field McGill rotation Therapy In-Vivo Dosimetry
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Rotational flow of Oldroyd-B nanofluid subject to Cattaneo-Christov double diffusion theory 被引量:2
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作者 A.HAFEEZ M.KHAN +1 位作者 A.AHMED J.AHMED 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第7期1083-1094,共12页
A nanofluid is composed of a base fluid component and nanoparticles, in which the nanoparticles are dispersed in the base fluid. The addition of nanoparticles into a base fluid can remarkably improve the thermal condu... A nanofluid is composed of a base fluid component and nanoparticles, in which the nanoparticles are dispersed in the base fluid. The addition of nanoparticles into a base fluid can remarkably improve the thermal conductivity of the nanofluid, and such an increment of thermal conductivity can play an important role in improving the heat transfer rate of the base fluid. Further, the dynamics of non-Newtonian fluids along with nanoparticles is quite interesting with numerous industrial applications. The present predominately predictive modeling studies the flow of the viscoelastic Oldroyd-B fluid over a rotating disk in the presence of nanoparticles. A progressive amendment in the heat and concentration equations is made by exploiting the Cattaneo-Christov heat and mass flux expressions. The characteristic of the Lorentz force due to the magnetic field applied normal to the disk is studied. The Buongiorno model together with the Cattaneo-Christov theory is implemented in the Oldroyd-B nanofluid flow to investigate the heat and mass transport mechanism. This theory predicts the characteristics of the fluid thermal and solutal relaxation time on the boundary layer flow. The von K′arm′an similarity functions are utilized to convert the partial differential equations(PDEs) into ordinary differential equations(ODEs). A homotopic approach for obtaining the analytical solutions to the governing nonlinear problem is carried out. The graphical results are obtained for the velocity field, temperature, and concentration distributions. Comparisons are made for a limiting case between the numerical and analytical solutions, and the results are found in good agreement. The results reveal that the thermal and solutal relaxation time parameters diminish the temperature and concentration distributions, respectively. The axial flow decreases in the downward direction for higher values of the retardation time parameter. The impact of the thermophoresis parameter boosts the temperature distribution. 展开更多
关键词 Oldroyd-B nanofluid rotating disk magnetohydrodynamic(MHD) Cattaneo-Christov theory analytical solution
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Effects of multiple shapes for steady flow with transformer oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks
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作者 M.RAHMAN M.TURKYILMAZOGLU Z.MUSHTAQ 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第2期373-388,共16页
In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating disks.The steady flow of hybrid nanofluids with transformer oil as the bas... In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating disks.The steady flow of hybrid nanofluids with transformer oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is considered.Several shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are studied.Every shape exists in the same volume of a nanoparticle.The leading equations(partial differential equations(PDEs))are transformed to the nonlinear ordinary differential equations(ODEs)with the help of similarity transformations.The system of equations takes the form of ODEs depending on the boundary conditions,whose solutions are computed numerically by the bvp4c MATLAB solver.The outputs are compared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation parameter,while it is decreased by the stretching values because of the lower disk.For the reaction rate parameter,the concentration boundary layer becomes shorter,and the activation energy component increases the rate at which mass transfers come to the higher disk but have the opposite effect on the bottom disk.The ranges of various parameters taken into account are Pr=6.2,Re=2,M=1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1. 展开更多
关键词 transformer oil Brinkman number skin friction coefficient double rotating disk Nusselt number Sherwood number
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Experimental Study on Flow past A Rotationally Oscillating Cylinder
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作者 GAO Yang-yang YIN Chang-shan +2 位作者 YANG Kang ZHAO Xi-zeng TAN Soon Keat 《China Ocean Engineering》 SCIE EI CSCD 2017年第4期495-503,共9页
A series of experiments was carried out to study the flow behaviour behind a rotationally oscillating cylinder at a low Reynolds number (Re=300) placed in a recirculation water channel. A stepper motor was used to r... A series of experiments was carried out to study the flow behaviour behind a rotationally oscillating cylinder at a low Reynolds number (Re=300) placed in a recirculation water channel. A stepper motor was used to rotate the cylinder clockwise- and- counterclockwise about its longitudinal axis at selected frequencies. The particle image velocimetry (PIV) technique was used to capture the flow field behind a rotationally oscillating cylinder. Instantaneous and time-averaged flow fields such as the vorticity contours, streamline topologies and velocity distributions were analyzed. The effects of four rotation angle and frequency ratios Fr (Fr=fn/fv, the ratio of the forcing frequency fn to the natural vortex shedding frequency fv) on the wake in the lee of a rotationally oscillating cylinder were also examined. The significant wake modification was observed when the cylinder undergoes clockwise-and-counterclockwise motion with amplitude of π, especially in the range of 0.6≤Fr≤1.0. 展开更多
关键词 rotational oscillation cylinder PIV frequency ratio wake flow pattern time-averaged flow field
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Rotational Flow in a Narrow Annular Gap Based on Lattice Boltzmann Method 被引量:1
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作者 WANG Yimiao ZHANG Jingyang ZHU Guiping 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第3期427-436,共10页
For comprehensive characteristics of flow in a gas bearing,lattice Boltzmann method(LBM)is applied for study of the two-dimensional flow between two eccentric cylinders with the inner one rotating at a high speed.The ... For comprehensive characteristics of flow in a gas bearing,lattice Boltzmann method(LBM)is applied for study of the two-dimensional flow between two eccentric cylinders with the inner one rotating at a high speed.The flow pattern and circumferential pressure distribution are discussed based on critical issues such as eccentricity ranging from 0.2 to 0.9,clearance ratio varying from 0.005 to 0.01 and rotating speed in the range of 3×104—1.8×105 r/min.The analysis and discussion on the circumferential pressure distribution affirmed the quasilinear relation between the extremum pressure and rotating speed.Furthermore,a high eccentricity and small clearance ratio contributes most to the fluctuation of the circumferential pressure distribution.The flow pattern inside the channel exhibits separation vortex under a large eccentricity.The conclusions drawn in this work give rise to prediction of the flow pattern in the gas bearing which is beneficial for evaluating the performance of as well as instructing the design and development. 展开更多
关键词 narrow annular eccentric rotating cylinders gas bearing lattice Boltzmann method(LBM)
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Theoretical research on rotational dispersion coefficient of fiber in turbulent shear flow of fiber suspension
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作者 高振宇 林建忠 李俊 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第3期289-296,共8页
The rotational dispersion coefficient of the fiber in the turbulent shear flow of fiber suspension was studied theoretically. The function of correlation moment between the different fluctuating velocity gradients of ... The rotational dispersion coefficient of the fiber in the turbulent shear flow of fiber suspension was studied theoretically. The function of correlation moment between the different fluctuating velocity gradients of the flow was built firstly. Then the expres- sion, dependent on the characteristic length, time, velocity and a dimensionless parameter related to the effect of wall, of rotational dispersion coefficient is derived. The derived expression of rotational dispersion coefficient can be employed to the inhomogeneous and non-isotropic turbulent flows. Furthermore it can be expanded to three-dimensional turbulent flows and serves the theoretical basis for solving the turbulent flow of fiber suspension. 展开更多
关键词 fiber suspension turbulent shear flow rotational dispersion coefficient EXPRESSION
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Improved Units of Measure in Rotational Mechanics
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作者 Richard James Petti 《World Journal of Mechanics》 2024年第1期1-7,共7页
The SI system of units in rotational mechanics yields correct numerical results, but it produces physically incorrect units of measure in many cases. SI units also violate the principle of general covariance—the gene... The SI system of units in rotational mechanics yields correct numerical results, but it produces physically incorrect units of measure in many cases. SI units also violate the principle of general covariance—the general rule for defining continuous coordinates and units in mathematics and mathematical physics. After 30+ years of wrestling with these problems, the ultimate authority on units of measure has declared that Newton–meter and Joule are not equivalent in rotational mechanics, as they are in the rest of physics. This article proposes a simple modification to SI units called “Nonstandard International units” (“NI units”) until a better name is agreed upon. NI units yield correct numerical results and physically correct units of measure, and they satisfy the principle of general covariance. The main obstacle to the adoption of NI units is the consensus among users that the radius of rotation should have the unit meter because the radius can be measured with a ruler. NI units assigned to radius should have units meter/radian because the radius is a conversion factor between angular size and circumferential length, as in arclength = rθ. To manage the social consensus behind SI units, the author recommends retaining SI units as they are, and informing users who want correct units that NI units solve the technical problems of SI units. 展开更多
关键词 rotational Mechanics Angular Unit TORQUE Moment of Inertia Angular Momentum General Covariance
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Analysis of flow response to fluctuation of rotational speed in a radial impeller
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作者 XIAO Jun ZHAO Yuanyang SHU Yue 《排灌机械工程学报》 EI CSCD 北大核心 2016年第8期693-702,共10页
By discretizing the convection terms with AUSM+-up scheme in the rotating coordinate system,a finite volume analysis code based on multi-block structured grids was developed independently so as to realize the numerica... By discretizing the convection terms with AUSM+-up scheme in the rotating coordinate system,a finite volume analysis code based on multi-block structured grids was developed independently so as to realize the numerical solving of internal flow fields of turbomachineries.Taking an unshrouded radial impeller with the working fluid of water vapour as the research object,the flow response to the fluctuation of rotational speed was calculated.By comparing the surface pressure profiles and velocity contours calculated by the code and commercial software respectively,the accuracy of flow solver was verified.The analysis of flow response data indicates that,as the working condition shifts closer towards the surge boundary,the response of flow parameters such as mass flow and aerodynamic torque will be more nonsynchronous with the fluctuation of rotational speed,and also the influence of density variation on mass flow variation will be smaller.Moreover,the transient variation region of working condition performance will deviate farther away from the steady performance curve as the working condition approaches the surge boundary.Compared to the working conditions with small mass flows,the distribution characteristics of pressure difference load on the blade surface vary little under large mass flow conditions.The reduction of fluctuation amplitude of rotational speed exerts no influence on abating the hysteresis of flow response. 展开更多
关键词 flow response AUSM+-up scheme fluctuation of rotating speed density variation pressure difference load
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Self-similarity of spanwise rotational motions’population trends in decelerating open-channel flow
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作者 Peng Zhang Yanchong Duan +4 位作者 Qiang Zhong Danxun Li Shengfa Yang Jiang Hu Wenjie Li 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2022年第3期213-219,共7页
Decelerating open-channel flow is a type of flow that gradually moves forward with decreasing velocity and increasing water depth.Although all flow parameters change along the streamwise direction,previous studies hav... Decelerating open-channel flow is a type of flow that gradually moves forward with decreasing velocity and increasing water depth.Although all flow parameters change along the streamwise direction,previous studies have revealed that these parameters’vertical distributions at different sections can be universally described with a single profile when being nondimensionalised by appropriate scales.This study focuses on the population trends of spanwise rotational motions at various sections along the main flow direction by particle imaging velocimetry(PIV)measurement.The wall-normal population distributions of density,radius,swirling strength,and convection velocity of the prograde and retrograde motions show similar trends in uniform open-channel flows.The dimensionless representation is invariant along the main flow direction.This study’s results indicate the self-similar characteristic of population trends of spanwise rotational motions prevails in decelerating open-channel flow. 展开更多
关键词 SELF-SIMILARITY Population trends Spanwise rotational motions Decelerating open-channel flow Equilibrium flow
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Retrospective Case Series on The Enduring Rotational Stability of The AcrySof IQ Toric Intraocular Lens in Cataract Patients Suffering from Myopia
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作者 Jie Luo Yang Liu +2 位作者 Bing Wang Lei Li Junyu Yang 《Journal of Clinical and Nursing Research》 2024年第3期207-214,共8页
Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case se... Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case series involving 78 patients.A total of 120 eyes with an axial length(AL)ranging from 24-30 mm and corneal astigmatism≥1.50 D underwent implantation of AcrySof IQ Toric IOL guided by the version navigation system.The eyes were divided into two groups based on AL.Group A included 60 eyes with high myopia(AL≥26 mm),while Group B consisted of eyes with low to moderate myopia(24 mm≤AL<26 mm).Data on the preoperative AL were collected.Measurements were taken for residual astigmatism,the best corrected visual acuity(BCDVA),corneal astigmatism,and IOL rotation occurring between 24-and 48-months post-surgery.The percentage of eyes with an IOL rotation of under 5°and 10°was analyzed.Results:The mean length of follow-up times was recorded as 34.27±4.98,and the average rotation was 2.73±1.29°.Group A exhibited a slightly higher average rotation of 2.87±1.31°,compared to the rotation of 2.59±1.27°observed in Group B.At both the 24-36 month and 26-48 month post-operation marks,the degree of IOL rotation did not show a statistically significant difference between the two groups,with none of the patients experiencing a rotation exceeding 10°(P>0.05).The percentage of rotation degrees under 5°was recorded as 98.22%.After the procedure,the BCDVA was 0.1322±0.03 LogMAR.There was a substantial increase in theχvalue after the operation as compared to the pre-operativeχ^(2) value(χ^(2)=76.79).The standard deviation of preoperative corneal astigmatism was statistically significant(P<0.05)at 2.17±1.08 D.Following the surgical procedure,the remaining astigmatism was measured at 0.41±0.26 D.The data showed a notable gap in statistical significance(t=4.281,P<0.05).Conclusion:The AcrySof Toric IOL was a reliable solution for managing corneal astigmatism in cataract patients with myopia,demonstrating excellent long-term rotational stability. 展开更多
关键词 ASTIGMATISM Long-term MYOPIA rotational stability
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The Rotationally Symmetric Flow of Micropolar Fluids in the Presence of an Infinite Rotating Disk
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作者 Atif Nazir Sajjad Hussain Mohammad Shafique 《Applied Mathematics》 2015年第2期430-439,共10页
The rotationally symmetric flow of a micropolar fluid in the presence of an infinite rotating disk has been studied numerically. The equations of motion are reduced to a system of ordinary differential equations, whic... The rotationally symmetric flow of a micropolar fluid in the presence of an infinite rotating disk has been studied numerically. The equations of motion are reduced to a system of ordinary differential equations, which in turn are solved numerically using SOR method and Simpson’s (1/3) rule. The results are calculated for different values of the parameter s (the ratio of angular velocities of disc and fluid) and the suction parameter a. Moreover, three different sets of the values of non-dimensional material constants related to micropolar behavior of the fluid have been chosen arbitrarily. The calculations have been carried out using three different grid sizes to check the accuracy of the results. The research concludes that the micropolar fluids flow resembles with that of Newtonian fluids when the material constants become close to zero. The comparison of these results is presented for possible values of the parameter s. 展开更多
关键词 MICROPOLAR FLUIDS rotatING DISK and Numerical Study
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Liquid Flow Characteristics inside Impeller Rotational Region of an Unbaffled Vessel Agitated with an Unsteadily Angularly Oscillating Impeller
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作者 Masanori Yoshida Keisuke Mikazuki +1 位作者 Kazuaki Yamagiwa Shuichi Tezura 《Journal of Chemistry and Chemical Engineering》 2011年第4期348-354,共7页
Characteristics of the liquid flow were studied in the impeller region for an unbaffied vessel agitated with an angularly oscillating impeller whose rotation proceeds while periodically reversing its direction at the ... Characteristics of the liquid flow were studied in the impeller region for an unbaffied vessel agitated with an angularly oscillating impeller whose rotation proceeds while periodically reversing its direction at the set angle, namely, rotating unsteadily with sinusoidal variation of the set amplitude. Measurement of the velocity of the liquid flow was performed, abreast of that of the torque of the shaft attached with the impeller. A disk turbine impeller with six flat blades was used in angular oscillation mode at the different amplitudes. The power characteristics were analyzed with the power number during one cycle of the angular oscillation consisting of a process for the impeller to stop and to reverse and that to rotate with a certain acceleration-deceleration in a uniform orientation. The power number in the process for the impeller to rotate exhibited slightly lower values compared with that of the identical design of impeller used in unidirectional rotation mode in a fully baffled vessel, being higher values in its process to stop and to reverse. Under such an operating condition in the amplitude, a time series of images was analyzed by particle tracking velocimetry (PTV) to characterize the fluctuation components of the velocities of the circumferential and radial flows inside the impeller rotational region. The impeller in its rotation process produced flows having a relatively large turbulence, independent of the amplitude condition. For the radial flow relating to the discharge flow, which contributes to transport of the turbulence throughout the vessel, operation at higher amplitude was clarified to be successful. 展开更多
关键词 Unbaffled agitated vessel unsteadily rotating impeller angular oscillation liquid flow impeller power
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Drag and Lift Force Acting on a Rotational Spherical Particle in a Logarithmic Boundary Flow
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作者 XU Wei-jiang CHE De-fu XU Tong-mo 《International Journal of Plant Engineering and Management》 2006年第2期111-118,共8页
The drag and lift forces acting on a rotational spherical particle in a logarithmic boundary flow are numerically studied. The effects of the drag velocity and rotational speed of the sphere on the drag force are exam... The drag and lift forces acting on a rotational spherical particle in a logarithmic boundary flow are numerically studied. The effects of the drag velocity and rotational speed of the sphere on the drag force are examined for the particle Reynolds number from 50 to 300 and for the dimensionless rotational angular speed of 0≤Ω≤1.0. The influence of dimensionless roughness height Z0 of the wall is also evaluated for z0 ≤ 10. The results show that the drag forces on a sphere both in a logarithmic flow and in a uniform unsheared flow increase with the increase of the drag velocity. For 50≤Rep≤300, -↑CD increases with decreased roughness height z0. The time-averaged drag coefficient is also significantly affected by rotational speed of the sphere and roughness height zo. The lift coefficient -↑CL increases with increased rotational speed and decreases with increased roughness height. 展开更多
关键词 rotational sphere drag coefficient lift coefficient VORTEX roughness height
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Co-rotational Oldroyd Fluid B Model for Spinning Flow of Liquid Crystalline Polymer
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作者 付强 《Journal of Southwest Jiaotong University(English Edition)》 2003年第2期152-156,共5页
The relationship between the extensional viscosity and material parameters was studied through the analytical formulas of stress and extensional viscosity. The differential equations were solved to obtain the relation... The relationship between the extensional viscosity and material parameters was studied through the analytical formulas of stress and extensional viscosity. The differential equations were solved to obtain the relationship between extensional viscosity and strain rates. The results obtained qualitatively agree with the experimental results. The study makes it practicable to simulate the rheologic behaviors of spinning flow of liquid crystalline polymer using co-rotational Oldroyd fluid B model. 展开更多
关键词 liquid crystalline polymer co-rotational Oldroyd fluid B model co-rotational convected derivative
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EXPERIMENTAL STUDY ON COHERENT VORTEX STRUCTURES IN DIFFERENTIALLY ROTATING QUASI TWO DIMENSIONAL ZONAL FLOW
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作者 何钰泉 梁宝社 刘书声 《Transactions of Tianjin University》 EI CAS 1998年第2期86-89,共4页
An experimental system for forming a rotating paraboloid shaped shallow water with a free surface was conducted to study coherent vortex structures in a differentially rotating quasi two dimensional zonal flow.Flow... An experimental system for forming a rotating paraboloid shaped shallow water with a free surface was conducted to study coherent vortex structures in a differentially rotating quasi two dimensional zonal flow.Flow visualization and laser light scattering techniques were used to obtain the information of spatial flow patterns.Experimental results show that the coexistence of Coriolis effect and strong shear in latitudinal zones may lead to formation of coherent vortices.Power spectra analysis and photographs which were taken in a reference frame rotating with the observed vortices also justified the emergence,drift and evolution of persistent vortices on the large scale.Locked vortex state manifests the cyclone and anticyclone asymmetry. 展开更多
关键词 coherent structure rotating shallow water shear flow
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Effects of Rotational Isomerism and Bond Length Alternation on Optical Spectra of FTC Chromophore in Solution
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作者 赵珂 韩广超 +1 位作者 张立立 贾海洪 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第1期75-81,I0004,共8页
Rotational isomerism effects on the optical spectra of a push-pull nonlinear optical chro-mophore 2-dicyanomethylen-3-cyano-4-f2-[E-(4-N,N-di(2-acetoxyethyl)-amino)-phenylene-(3,4-dibutyl)-thien-5]-E-vinylg-5,5-... Rotational isomerism effects on the optical spectra of a push-pull nonlinear optical chro-mophore 2-dicyanomethylen-3-cyano-4-f2-[E-(4-N,N-di(2-acetoxyethyl)-amino)-phenylene-(3,4-dibutyl)-thien-5]-E-vinylg-5,5-dimethyl-2,5-dihydrofuran (FTC) in a few solvents have been studied using the time-dependent density functional theory in combination with the polarizable continuum model. It is shown that the maximum absorption peaks of the ro-tamers have difference of nearly 30 nm both in vacuum and in solutions. The population of the rotamers changes a lot in different solvents. Based on the geometries optimized by Hartree-Fock method, the Maxwell-Boltzmann averaged absorption has been calculated and the maximum absorption peak is in good agreement with experiment. It indicates that the bond length alternation can have an important effect on the optical spectra. 展开更多
关键词 rotational isomerism Bond length alternation One-photon absorption Po-larizable continuum model
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Differential Interference Angle of Collision-induced Rotational Energy Transfer in Na_2(A^1∑_u^+,v=8-b^3∏_(0u),v=14)-Na System
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作者 李健 李永庆 +1 位作者 王伟丽 马凤才 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第6期469-472,共4页
Here wc report calculation of the differential interference angles (including b≤p gild b≥p ) for singlet-triplet mixed states of Na2(A^1∑u^+,ν=8-b^3∏0u,ν=14) system in collision with Na, in order to study t... Here wc report calculation of the differential interference angles (including b≤p gild b≥p ) for singlet-triplet mixed states of Na2(A^1∑u^+,ν=8-b^3∏0u,ν=14) system in collision with Na, in order to study the collision- induced quantum interference on rotational energy transfer in an atom-diatom system. The calculation is based on the first-order Born approximation of time-dependent perturbation theory, and the anisotropic Lennard-Jones intcraction potentials are also employed, The relationships between differential interference angle and impact parameter, including collision diameter and velocity, are obtained, 展开更多
关键词 rotational energy transfer Collision induced quantum interference Interference angle
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