期刊文献+
共找到3,434篇文章
< 1 2 172 >
每页显示 20 50 100
ST-LSTM-SA:A New Ocean Sound Velocity Field Prediction Model Based on Deep Learning 被引量:1
1
作者 Hanxiao YUAN Yang LIU +3 位作者 Qiuhua TANG Jie LI Guanxu CHEN Wuxu CAI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第7期1364-1378,共15页
The scarcity of in-situ ocean observations poses a challenge for real-time information acquisition in the ocean.Among the crucial hydroacoustic environmental parameters,ocean sound velocity exhibits significant spatia... The scarcity of in-situ ocean observations poses a challenge for real-time information acquisition in the ocean.Among the crucial hydroacoustic environmental parameters,ocean sound velocity exhibits significant spatial and temporal variability and it is highly relevant to oceanic research.In this study,we propose a new data-driven approach,leveraging deep learning techniques,for the prediction of sound velocity fields(SVFs).Our novel spatiotemporal prediction model,STLSTM-SA,combines Spatiotemporal Long Short-Term Memory(ST-LSTM) with a self-attention mechanism to enable accurate and real-time prediction of SVFs.To circumvent the limited amount of observational data,we employ transfer learning by first training the model using reanalysis datasets,followed by fine-tuning it using in-situ analysis data to obtain the final prediction model.By utilizing the historical 12-month SVFs as input,our model predicts the SVFs for the subsequent three months.We compare the performance of five models:Artificial Neural Networks(ANN),Long ShortTerm Memory(LSTM),Convolutional LSTM(ConvLSTM),ST-LSTM,and our proposed ST-LSTM-SA model in a test experiment spanning 2019 to 2022.Our results demonstrate that the ST-LSTM-SA model significantly improves the prediction accuracy and stability of sound velocity in both temporal and spatial dimensions.The ST-LSTM-SA model not only accurately predicts the ocean sound velocity field(SVF),but also provides valuable insights for spatiotemporal prediction of other oceanic environmental variables. 展开更多
关键词 sound velocity field spatiotemporal prediction deep learning self-allention
下载PDF
Inverting the rock mass P-wave velocity field ahead of deep buried tunnel face while borehole drilling
2
作者 Liu Liu Shaojun Li +5 位作者 Minzong Zheng Dong Wang Minghao Chen Junbo Zhou Tingzhou Yan Zhenming Shi 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第5期681-697,共17页
Imaging the wave velocity field surrounding a borehole while drilling is a promising and urgently needed approach for extending the exploration range of the borehole point.This paper develops a drilling process detect... Imaging the wave velocity field surrounding a borehole while drilling is a promising and urgently needed approach for extending the exploration range of the borehole point.This paper develops a drilling process detection(DPD)system consisting of a multifunctional sensor and a pilot geophone installed at the top of the drilling rod,geophones at the tunnel face,a laser rangefinder,and an onsite computer.A weighted adjoint-state first arrival travel time tomography method is used to invert the P-wave velocity field of rock mass while borehole drilling.A field experiment in the ongoing construction of a deep buried tunnel in southwestern China demonstrated the DPD system and the tomography method.Time-frequency analysis of typical borehole drilling detection data shows that the impact drilling source is a pulse-like seismic exploration wavelet.A velocity field of the rock mass in a triangular area defined by the borehole trajectory and geophone receiving line can be obtained.Both the borehole core and optical image validate the inverted P-wave velocity field.A numerical simulation of a checkerboard benchmark model is used to test the tomography method.The rapid convergence of the misfits and consistent agreement between the inverted and observed travel times validate the P-wave velocity imaging. 展开更多
关键词 Deep buried tunnel Wave velocity field Borehole drilling Tomography Rock mass
下载PDF
Herrmann Method of Analyzing Structure Design Velocity Field
3
作者 邹文胜 左正兴 +2 位作者 冯慧华 廖日东 张红光 《Journal of Beijing Institute of Technology》 EI CAS 2001年第1期93-100,共8页
The shape optimization is studied by adopting the domain integrated method which is based on the calculus of variations during the shape design sensitivity analysis. A new method of improving the efficiency of the de... The shape optimization is studied by adopting the domain integrated method which is based on the calculus of variations during the shape design sensitivity analysis. A new method of improving the efficiency of the design velocity field analysis and the quality of the finite element method (FEM) mesh is put forward. The sensitivity analysis which is based on the calculus of variations is used in the shape optimization. The design velocity field is solved by Herrmann method. An example shows that both the quality of the FEM mesh and the efficiency of the computing of the design velocity field are improved by Herrmann method. So the effect and the efficiency of the shape optimization are guaranteed. If using sensitivity analysis which is based on the calculus of variations in the shape optimization, the sensitivity analysis can be a relatively independent module. The efficiency of computing the design velocity field and the quality of mesh will be improved by using Herrmann method. 展开更多
关键词 design velocity field shape optimization sensitivity analysis Herrmann methods
下载PDF
3D FEM simulation of flow velocity field for 5052 aluminum alloy multi-row sprocket in cold semi-precision forging process 被引量:1
4
作者 程旺军 池成忠 +3 位作者 王永祯 林鹏 赵日红 梁伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期926-935,共10页
Based on the design of the multi-row sprocket with a new tooth profile,a cold semi-precision forging process for manufacturing 5052 aluminum alloy multi-row sprocket was presented.Through simulating the forging proces... Based on the design of the multi-row sprocket with a new tooth profile,a cold semi-precision forging process for manufacturing 5052 aluminum alloy multi-row sprocket was presented.Through simulating the forging process of 5052 aluminum alloy sprocket billet with 3D rigid-viscoplastic FEM,both the distributions of flow velocity field in axial(U_Z),radial(U_R) and circumferential(U_θ) directions and the curves of velocity component in different deformation regions were respectively obtained.By comparison and analysis of the velocity varying curves,the velocity component relation conditions for filling the die cavity were clarified.It shows that when the die cavity is almost fully filled,the circumferential velocity U_θ increases sharply,implying that U_θplays a key role in fully filling the die cavity. 展开更多
关键词 multi-row sprocket cold semi-precision forging 5052 aluminum alloy flow velocity field 3D FEM
下载PDF
A Laboratory Modeling of the Velocity Field in the Convective Boundary Layer with the Particle Image Velocimetry Technique 被引量:5
5
作者 李萍阳 蒋维楣 +1 位作者 孙鉴泞 袁仁民 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2003年第4期631-637,共7页
Based on the research of the convective boundary layer (CBL) temperature field in a convective tank, this paper studies the characteristics of the CBL velocity field in the convective tank. Aluminium powder (400 order... Based on the research of the convective boundary layer (CBL) temperature field in a convective tank, this paper studies the characteristics of the CBL velocity field in the convective tank. Aluminium powder (400 orders) is used as a tracer particle in the application of the particle image velocimetry (PIV) technique. The experiment demonstrates: the velocity distribution in the mixed layer clearly possesses the characteristics of CBL thermals; the velocity distribution in the top zone of the mixed layer shows entrainment layer characteristics; the vertical distribution of turbulent characteristic variables is reasonable, which is similar to field observations and other tank results; the error analysis demonstrates the validity of aluminium powder, which implies the reliability of the results. 展开更多
关键词 velocity field convective boundary layer (CBL) convective water tank PIV technique
下载PDF
A Study of Lift Force and Instantaneous Velocity Field Around an Oscillating Circular Cylinder 被引量:2
6
作者 C.A.Greated 《China Ocean Engineering》 SCIE EI 1997年第4期419-430,共12页
Force measurements of oscillatory flow acting on a single circular cylinder have been carried out. The experiments were done by oscillating a circular cylinder in still water. Instantaneous forces and velocity fields ... Force measurements of oscillatory flow acting on a single circular cylinder have been carried out. The experiments were done by oscillating a circular cylinder in still water. Instantaneous forces and velocity fields around the cylinder were measured by Particle Image Velocimetry (PIV). The Keulegan-Carpenter number (KC) varied in the range from 5 to 20 and the viscous parameter beta = Re / KC was set at 500 (Re is Reynolds number). It was found that the strength and frequency of the lift force increased with KC number, the main frequency of the lift force being three times the frequency of the oscillatory flow at KC = 20. The movement and strength of the vortices around the cylinder are discussed for different KC numbers. 展开更多
关键词 particle image velocimetry oscillatory polo single circular cylinder force measurement lift force velocity field vortex pattern VORTICITY
下载PDF
Face stability of shield tunnels considering a kinematically admissible velocity field of soil arching 被引量:5
7
作者 Wei Li Chengping Zhang +2 位作者 Dingli Zhang Zijian Ye Zhibiao Tan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第2期505-526,共22页
Existing mechanism of simulating soil movement at tunnel face is generally based on the translational or rotational velocity field,which is,to some extent,different from the real soil movement in the arching zone.Nume... Existing mechanism of simulating soil movement at tunnel face is generally based on the translational or rotational velocity field,which is,to some extent,different from the real soil movement in the arching zone.Numerical simulations are carried out first to investigate the characteristics of the velocity distribution at tunnel face and above tunnel vault.Then a new kinematically admissible velocity field is proposed to improve the description of the soil movement according to the results of the numerical simulation.Based on the proposed velocity field,an improved failure mechanism is constructed adopting the spatial discretization technique,which takes into account soil arching effect and plastic deformation within soil mass.Finally,the critical face pressure and the proposed mechanism are compared with the results of the numerical simulation,existing analytical studies and experimental tests to verify the accuracy and improvement of the presented method.The proposed mechanism can serve as an alternative approach for the face stability analysis. 展开更多
关键词 Tunnel face stability velocity field Failure pattern Improved failure mechanism Critical face pressure
下载PDF
Particle Agglomeration in Bipolar Barb Agglomerator Under AC Electric Field 被引量:6
8
作者 黄超 马秀琴 +3 位作者 孙优善 王美艳 张长平 娄越雅 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第4期317-320,共4页
The development of an efficient technology for removing fine particles in flue gas is essential as the haze is becoming more and more serious.To improve agglomeration effectiveness of fine particles,a dual zone electr... The development of an efficient technology for removing fine particles in flue gas is essential as the haze is becoming more and more serious.To improve agglomeration effectiveness of fine particles,a dual zone electric agglomeration device consisting of a charging chamber and an agglomeration chamber with bipolar barb electrodes was developed.The bipolar barb electric agglomerator with a polar distance of 200 mm demonstrates good agglomeration effectiveness for particles with a size less than 8.0μm under applied AC electric field.An optimal condition for achieving better agglomeration effectiveness was found to be as follows:flue gas flow velocity of3.00 m/s,particle concentration of 2.00 g/m^3,output voltage of 35 kV and length of the barb of16 ram.In addition,4.0-6.0μm particles haste the best effectiveness with the variation of particle volume occupancy of-3.2. 展开更多
关键词 fine particles agglomeration bipolar barb AC electric field
下载PDF
Numerical simulation of temperature and velocity fields in plasma spray 被引量:2
9
作者 范群波 王鲁 王富耻 《Journal of Central South University of Technology》 EI 2007年第4期496-499,共4页
Based on the turbulence jet model, with respect to Ar-He mixture plasma gas injecting to ambient atmosphere, the temperature filed and velocity field under typical working conditions were investigated. Given the condi... Based on the turbulence jet model, with respect to Ar-He mixture plasma gas injecting to ambient atmosphere, the temperature filed and velocity field under typical working conditions were investigated. Given the conditions of I=900 A, FAr= 1.98 m^3/h, FEe=0.85 m^3/h, it is found that both the temperature and the velocity undergo a plateau region near the nozzle exit (0-10 mm) at the very first stage, then decrease abruptly from initial 13 543 K and 778.2 m/s to 4 000 K and 260.0 m/s, and finally decrease slowly again. Meanwhile, the radial temperature and radial velocity change relatively slow. The inner mechanism for such phenomena is due to the complex violent interaction between the high-temperature and high-velocity turbulent plasma jet and the ambient atmosphere. Compared with traditional methods, the initial working conditions can be directly related to the temperature and velocity fields of the plasma jet by deriving basic boundary conditions. 展开更多
关键词 plasma spray plasma jet temperature field velocity field
下载PDF
Effects of Surface Etch Hole Fault on the Velocity Field in Microchannel Reactors 被引量:2
10
作者 尤学一 李胜华 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第6期919-924,共6页
Microchannel reactors are commonly used in micro-chemical technology. The performance of microreactors is greatly affected by the velocity field in the microchannel. The flow field is disturbed by the cylindrical etch... Microchannel reactors are commonly used in micro-chemical technology. The performance of microreactors is greatly affected by the velocity field in the microchannel. The flow field is disturbed by the cylindrical etch holes caused by air dust on the microchannel surface during its processing procedure. In this approach, a two-dimensional computational fluid dynamics (CFD) model is put forward to study the effect of etch holes on flow field. The influenced area of single or two concave etch holes is studied for the case of laminar flow. The hole diameter, the Reynolds number and the distance between the center of holes are found to have influences on the flow field. Numerical results indicate that the effects of etch hole on the flow field should be evaluated and the way of choosing the economic class of cleanroom for microreactor manufacture is presented. 展开更多
关键词 MICROCHANNEL processing faults etch holes computational fluid dynamics velocity field
下载PDF
Experimental studies on flow visualization and velocity field of compression ramp with different incoming boundary layers 被引量:1
11
作者 武宇 易仕和 +2 位作者 何霖 陈植 朱杨柱 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第11期384-395,共12页
Experimental studies which focus on flow visualization and the velocity field of a supersonic laminar/turbulent flow over a compression ramp were carried out in a Mach 3.0 wind tunnel. Fine flow structures and velocit... Experimental studies which focus on flow visualization and the velocity field of a supersonic laminar/turbulent flow over a compression ramp were carried out in a Mach 3.0 wind tunnel. Fine flow structures and velocity field structures were obtained via NPLS (nanoparticle-tracer planar laser scattering) and PIV (particle image velocimetry) techniques, time- averaged flow structures were researched, and spatiotemporal evolutions of transient flow structures were analyzed. The flow visualization results indicated that when the ramp angles were 25~, a typical separation occurred in the laminar flow, some typical flow structures such as shock induced by the boundary layer, separation shock, reversed flow and reattachment shock were visible clearly. While a certain extent separation occurred in turbulent flow, the separation region was much smaller. When the ramp angles were 28~, laminar flow separated further, and the separation region expanded evidently, flow structures in the separation region were complex. While a typical separation occurred in turbulent flow, reversed flow structures were significant, flow structures in the separation region were relatively simple. The experimental results of velocity field were corresponding to flow visualization, and the velocity field structures of both compression ramp flows agreed with the flow structures well. There were three layered structures in the U component velocity, and the V component velocity appeared like an oblique "v". Some differences between these two compression ramp flows can be observed in the velocity profiles of the shear layer and the shearing intensity. 展开更多
关键词 compression ramp incoming boundary layer fine flow structure velocity field
下载PDF
Velocity Field and Variation of Wall Thickness During Tube Dieless Upsetting 被引量:1
12
作者 王忠堂 栾瑰馥 张士宏 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第2期218-222,共5页
Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (1+R_s)^(1/2) (Rs is sectional increase ratio of tube), the theoretical calculated results ... Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (1+R_s)^(1/2) (Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (to/tf) reduce. 展开更多
关键词 dieless upsetting TUBE wall thickness velocity field
下载PDF
Impact of a background velocity field on solidification growth of single-crystal nuclei using the PF-LBM 被引量:1
13
作者 Liang Wenqing Lei Gang +5 位作者 Xun Qining Shu Zhiyong Wang Tianxiang Qian Hua Zhao Dongliang Zheng Xiaohong 《Journal of Southeast University(English Edition)》 EI CAS 2022年第4期373-382,共10页
To promote/inhibit ice formation in the natural environment and industrial systems,the growth and evolution process of ice single-crystal nuclei were simulated using the phase field-lattice Boltzmann method(PF-LBM),an... To promote/inhibit ice formation in the natural environment and industrial systems,the growth and evolution process of ice single-crystal nuclei were simulated using the phase field-lattice Boltzmann method(PF-LBM),and the influence of a background flow field on the growth of single-crystal nucleus dendrites was also analyzed.The results show that the flow field makes dendrite growth asymmetric.The growth of dendrites is more developed on the upstream side than on the downstream side.The dendrite tip growth rate and tip radius are greater on the upstream side than on the downstream side.The solid phase ratio is greater with a background flow field than without one.The higher the flow velocity is,the more developed the dendrites on the upstream side,the faster the dendrites grow,and the higher the dendrite tip growth rate.The dendrites on the backflow side have a lower flow rate and a lower degree of supercooling than those on the upstream side,which inhibits the solidification process,the growth rate is slow,and the dendrites are underdeveloped. 展开更多
关键词 single-crystal nucleus coupled velocity field simulation lattice Boltzmann method
下载PDF
Magnetic and Velocity Fields in Flare Regions
14
作者 Li Wei 1(Beijing Astronomical Observatory, The Chinese Academy of Sciences, Beijing 100012,China) 2(National Astronomical Observatories, The Chinese Academy of Sciences, Beijing 100012, China) 《天文研究与技术》 CSCD 1999年第S1期175-181,共7页
This paper reviews observations of the solar magnetic and velocity fields in active regions where flares produce. Our study includes (1) the relationship among the magnetic fields, Doppler velocity fields and flares; ... This paper reviews observations of the solar magnetic and velocity fields in active regions where flares produce. Our study includes (1) the relationship among the magnetic fields, Doppler velocity fields and flares; (2) the relationship between magnetic shear and flares; (3) the relationship among electric currents, electric helicity and flares; (4) the evidence for non-potential magnetic field. 展开更多
关键词 Magnetic and velocity fields in Flare Regions
下载PDF
A Computation on Velocity Field of the Post-flare Loop System of August 17, 1989 被引量:1
15
作者 Gu Xiaoma 1,2 , Dun Jinping 1, Zhong Shuhua 1 1 (Yunnan Observatory, The Chinese Academy of Sciences, Kunming 650011, China) 2 (United Laboratory of Optical Astronomy, The Chinese Academy of Sciences) (e mail:ssg@public. km. yn. cn) 《天文研究与技术》 CSCD 1999年第S1期414-418,共5页
The observational line of sight velocity fields of a large post flare loop(PFL) system on August 17,1989 were derived based on “multi cloud model” (MCM) method from the Hβ spectral data obtained with the two dimens... The observational line of sight velocity fields of a large post flare loop(PFL) system on August 17,1989 were derived based on “multi cloud model” (MCM) method from the Hβ spectral data obtained with the two dimensional Multi Waveband Spectra Spectro Helio Graph (MW SSHG) at Yunnan Observatory. In order to explain the fundamental features of the velocity fields observed,an assumption and approximation to be taken into account that the matter within a loop system rises up from the loop foot to the loop top along the loop leg in a helical magnetic line under the combined action of solar gravity, magnetic stress and a gradient of atmospheric pressure in the loop system, and a theoretical velocity field of the loop system was calcuated with the aid of MHD theory. From a comparison of both velocity fields, it is found that the computed velocity field is basically similar with the observed one. It indicates that the assumption and approximation mentioned above are suitable basically. 展开更多
关键词 SUN POST FLARE LOOPS SUN velocity field
下载PDF
Establishment and analyses on the unified horizontal crustal velocity fields in the Chinese mainland 被引量:24
16
作者 李延兴 胡新康 +4 位作者 黄城 朱文耀 帅平 胡小工 张中伏 《地震学报》 CSCD 北大核心 2001年第5期453-459,共7页
The related data of GPS networks in the Chinese mainland and its peripheral areas collected from internet sites in the paper.And various data fusion methods are presented based on the collected GPS data.Thus the unifi... The related data of GPS networks in the Chinese mainland and its peripheral areas collected from internet sites in the paper.And various data fusion methods are presented based on the collected GPS data.Thus the unified horizontal crustal velocity fields can be established in Chinese mainland and its peripheral areas.The available data of 423 GPS sites are applied to the velocity fields and its area gets to 1.2×107.By analyzing the velocity fields ,the basic spatial distribution feature of the horizontal crustal motion in the Chinese mainland and its peripheral area can be obtained preliminarily.Meanwhile,the range of the velocity fields in the Chinese mainland affected by the collision force of India plate to Eurasia plate and the problem of principal direction of the force from India plate are discussed. 展开更多
关键词 GPS网 速度场融合 地壳水平运动 中国大陆 空间分布 全球定位系统
下载PDF
Simulation of Liquid Velocity Field in a Gas-Liquid Bubble Column
17
作者 张敏卿 范敏英 +1 位作者 余国琮 王树立 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1998年第4期28-36,共9页
A simplified turbulent model and a modified k-Σ two equation model are proposed todescribe the liquid velocity profiles in a bubble column taking into consideration of the effect of gasdrag force and gas hold-up.In t... A simplified turbulent model and a modified k-Σ two equation model are proposed todescribe the liquid velocity profiles in a bubble column taking into consideration of the effect of gasdrag force and gas hold-up.In the simplified mode1 the Reynolds equation of motion was adoptedand the turbulent viscosity was calculated from an empirical correlation which was deduced fromour experimental data.The calculated liquid velocity profiles were compared between the proposedmodel and the standard k-Σ two equation model as well as experimental data.The result shows thatthe proposed model simulates and predicts the liquid velocity field most satisfactorily and in goodagreement with the experimental measurement. 展开更多
关键词 BUBBLE COLUMN LIQUID velocity field TURBULENT model
下载PDF
NUMERICAL SIMULATION AND ANALYSIS ON THE VELOCITY FIELD IN BATH OF A ROUND ELECTRIC CLEANING FURNACE
18
作者 Zhou Ping Mei Chi +1 位作者 Zhou Shuiliang Wang Qianpu(Department of Applied Physics and Heat Engineering, Central SouthUniversity of Technology, Changsha 410083, China) 《Journal of Central South University》 SCIE EI CAS 1997年第1期54-57,共4页
The flowing behavior of liquid slag has an important effect on the heat efficiency, recovery ratio ofvaluable metals and life span of the electric cleaning furnace. The velocity procedure using "κ-ε" model... The flowing behavior of liquid slag has an important effect on the heat efficiency, recovery ratio ofvaluable metals and life span of the electric cleaning furnace. The velocity procedure using "κ-ε" model wasdeveloped under the cylindrical coordinate system. The procedure is used to calculate the velocity field ofmolten slag. The forces acting on molten slag were analyzed. The calculating method of electromagnetic forcewas described. The discrete equations, which were solved by using SIMPLE algorithm, were generated bymeans of interlace grids and control volume. The boundary layers near the solid wall were treated as wallfunction. The velocity distribution is obtained. The results show that the velocity of molten slag varies withdifferent horizontal sections. There are six eddies in the surface layer of molten slag. A large circle is formedin the sections below the electrodes, while the longitudinal section includes two large circles around the electrode. The influences of the features of the velocity field on the operation in the electric cleaning furnace arediscussed in detail. 展开更多
关键词 NUMERICAL simulation velocity field ELECTRIC FURNACE
下载PDF
An analytical model of hot rolling force for a thick plate by combining globally optimal approximation yield criterion and egg-circular velocity field
19
作者 Shun-hu Zhang Yi Zhang +1 位作者 Wen-hao Tian Yan Li 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2024年第3期647-659,共13页
For the sake of solving the problem that it is difficult to be integrated for the Mises specific plastic power due to its nonlinearity,a new linear criterion,named the globally optimal approximation criterion,is const... For the sake of solving the problem that it is difficult to be integrated for the Mises specific plastic power due to its nonlinearity,a new linear criterion,named the globally optimal approximation criterion,is constructed by the polygonal approximation to the Mises circle.The new criterion is proved to be the linear function of the principal stress componentsσ1,σ2 andσ3 and the trajectory of it on theπ-plane is a non-equiangular but equilateral dodecagon intersecting the Mises circle.The theoretical results of the current criterion described by the Lode stress parameters are in excellent accordance with the experimental results.Meanwhile,according to the trend that the metallic flow velocity between rollers aggrandizes gradually from the inlet to the outlet during the hot rolling of a thick plate,a biomimetic velocity field is proposed in which the horizontal velocity component fits the egg-circular curve distribution.The velocity field and its simulated results agree quite well.Subsequently,using the determined linear criterion,energy analysis of the constructed velocity field is utilized to obtain the interior deformation power,while the vector decomposition approach is utilized to obtain the frictional power and shear power.On this basis,the overall power is obtained and the analytical solutions are generated for the rolling torque,rolling force and the coefficient of the stress state under different egg curves by minimizing the neutral angle.Furthermore,the parameter optimization of the characteristic parameterρwhich affects the slope of the egg-circular curve is carried out and the best egg-circular curve which can minimize the energy consumption is determined.The best agreement between the theoretical and observed values of rolling force and rolling torque is under this curve,and the mean relative errors of the rolling torque and rolling force are no more than 2.93%,while the maximum error is no more than 8.35%. 展开更多
关键词 Yield criterion Plastic deformation Rolling force velocity field Analytical solution
原文传递
Research on Multi-Wave Pore Pressure Prediction Method Based on Three Field Velocity Fusion
20
作者 Junlin Zhang Huan Wan +2 位作者 Yu Zhang Yumei He Linlin Dan 《Journal of Geoscience and Environment Protection》 2024年第6期269-278,共10页
The optimization of velocity field is the core issue in reservoir seismic pressure prediction. For a long time, the seismic processing velocity analysis method has been used in the establishment of pressure prediction... The optimization of velocity field is the core issue in reservoir seismic pressure prediction. For a long time, the seismic processing velocity analysis method has been used in the establishment of pressure prediction velocity field, which has a long research period and low resolution and restricts the accuracy of seismic pressure prediction;This paper proposed for the first time the use of machine learning algorithms, based on the feasibility analysis of wellbore logging pressure prediction, to integrate the CVI velocity inversion field, velocity sensitive post stack attribute field, and AVO P-wave and S-wave velocity reflectivity to obtain high-precision seismic P and S wave velocities. On this basis, high-resolution formation pore pressure and other parameters prediction based on multi waves is carried out. The pressure prediction accuracy is improved by more than 50% compared to the P-wave resolution of pore pressure prediction using only root mean square velocity. Practice has proven that the research method has certain reference significance for reservoir pore pressure prediction. 展开更多
关键词 velocity field RESOLUTION Machine Learning AVO Inversion Pore Pressure
下载PDF
上一页 1 2 172 下一页 到第
使用帮助 返回顶部