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Synthetic Jet Control on the Propulsion Behavior of a Foil in Plunge-pitch Motion

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Journal of Bionic Engineering 2020年第2期17卷 303-314页

作者： Yadong Li guoqing zhou Jie Wu Liaoning General Aviation Academy Shenyang Aerospace UniversityShenyang 110136China College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The Synthetic Jet(S J)control on the propulsion behavior of a foil in plunge-pitch motion is examined in this work by numerical *** elliptic foil with ratio of 8 performs the plunge and pitch motions synchronously.A pair of SJs with the same frequency and strength is integrated into the upper and lower surfaces of the *** a result,the local flow field around the foil could be obviously modified by the *** the Reynolds number of 200,the effects of the inclined angle between the jet direction and the chord line,the phase angle between the SJs and the flapping motion as well as the location of SJ on the propulsion performance are systematically *** with the pure plunging and pitching foil,it is indicated that the enhancement of mean thrust and propulsive efficiency can be obtained by the SJs with suitable working *** on the numerical analysis,it is found that the jet flow on the foil surfaces,which changes the local pressure distribution to increase the pressure difference between upper and lower surfaces,can benefit the propulsion behavior of the flapping foil.

关键词： propulsion behavior plunge-pitch motion elliptic foil synthetic jet

Infrared radiation method for measuring ice segregation temperature of artificially frozen soils

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International Journal of Mining Science and Technology 2012年第1期22卷 35-40页

作者： zhou guoqing Zhang Qi Xu Zhiwei zhou Yang State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining&TechnologyXuzhou 221008China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

In order to study the evolution of the freezing fringe and final lenses of frost susceptible soils and advance the understanding of frost heave and mechanism of frost heave control, we used an open one-dimensional frost heave test system of infrared radiation technology, instead of a traditional thermistor method. Temperatures of the freezing fringe and segregated ice were measured in a non-contact mode. The results show that accurate and precise temperatures of ice segregation can be obtained by infrared thermal imaging systems. A self-developed inversion program inverted the temperature field of frozen soils. Based on our analysis of temperature variation in segregated ice and our study of the relationship between temperature and rate of ice segregation in cooling and warming processes during intermittent freezing, the mechanism of decreasing frost heave of frozen soils by controlling the growth of final lenses with an intermittent freezing mode, can be explained properly.

关键词： One-dimensional freezing Final lens Ice segregation temperature measurement Infrared radiation method

Bearing capacity of surface circular footings on granular material under low gravity fields

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第3期13卷 612-625页

作者： Pin-Qiang Mo guoqing zhou Feng Gao Ruilin Li State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil EngineeringChina University of Mining and TechnologyXuzhou221116China School of Civil Engineering Central South UniversityChangsha410075China

Low gravity fields have been simulated through magnetic acceleration to conduct experimental study on bearing capacity of circular footings on a type of crushable planetary regolith simulant,which has comparable density and particle size distribution of lunar *** loadesettlement responses of surface spread footings are obtained by investigating the relative density,footing size and gravity *** the hyperbolic asymptote method,normalised foundation stiffness and ultimate bearing capacity are obtained by curve fitting and predicted by power functions using multivariate nonlinear *** results show that the nonlinear gravity effect is not negligible,related to stress condition,soil dilatancy and mobilised friction angle.A cone penetration test(CPT)-based method for prediction of bearing capacity is proposed with correlations between ultimate bearing capacity of footings and shallow penetration stiffness of CPTs,avoiding the uncertainties of soil property *** of allowable bearing capacity and footing influence zone in consideration of footing size and gravity effects could therefore improve the design of shallow foundations on the Moon and Mars,and provide new understandings and potential implications to the bearing capacity of shallow foundations on crushable granular material in both terrestrial and extraterrestrial geotechnical engineering.

关键词： Low gravity fields Bearing capacity Shallow foundation Planetary regolith simulant

Fractal analysis of thermal conduction of loose coal

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Mining Science and Technology 2010年第6期20卷 831-834,838页

作者： WANG Yijiang zhou guoqing WEI Yazhi zhou Yang School of Mechanics & Civil Engineering China University of Mining & Technology Xuzhou 221116 China State Key Laboratory of Geomechanics & Deep Underground Engineering China University of Mining & Technology Xuzhou 221008 China

For deep mining engineering, heat transfer of coal mass is a vital factor in the thermal environment of coal mines. In order to study the thermal conduction mechanism, we obtained gray images of coal mass microstructure by scanning samples with a digital microscope. With the use of Matlab, these gray images were transformed into binary images, which were then transformed into a corresponding matrix consisting only of the values 0 and 1. According to the calculation method of box-counting dimension, we calculated the fractal dimension of the loose coal to be approximately 1.86. The thermal conductivity expressions of loose coal were derived based on the simulation method of thermal resistance. We calculated the thermal conductivity of loose coal by using a fractal model and compared the calculated values with our experimental data. The results show that the test data show an encourag-ing agreement with the calculated values. Hence fractal theory is a feasible method for studying thermal conductivity of loose coal.

关键词： loose coal thermal conductivity fractal theory box-counting dimension

Uncertainties of thermal boundaries and soil properties on permafrost table of frozen ground in Qinghai-Tibet Plateau

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第3期13卷 671-681页

作者： Tao Wang Erxing Peng Lijiang Xia guoqing zhou Jianzhou Wang State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil EngineeringChina University of Mining and TechnologyXuzhou221116China State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu730000China School of Food Engineering Ludong UniversityYantai264025China

In the permafrost regions of the Qinghai-Tibet Plateau(QTP),the permafrost table has a significant effect on the stability of geotechnical *** thermal boundaries and soil properties are the key factors affecting the permafrost *** geological environments and human activities can lead to the uncertainties of thermal boundaries and soil *** this paper,an array of field experiments and Monte Carlo(MC)simulations of thermal boundaries and soil properties are carried *** coefficient of variation(COV),scale of fluctuation(SOF),and autocorrelation distance(ACD)of uncertainties of thermal boundaries and soil properties are investigated.A stochastic analysis method of the probabilistic permafrost table is then proposed,and the statistical properties of permafrost table on the QTP are computed by self-compiled *** proposed stochastic analysis method is verified with the calculated and measured temperature *** to the relationship between ACD and SOF for the five theoretical autocorrelation functions(ACFs),the effects of ACF,COV,and ACD of soil properties and the COV of thermal boundaries on the permafrost tables are *** results show that the effects of different ACFs of soil properties on the standard deviation(SD)of permafrost table depth are not *** SD of permafrost table depth increases with time,and the larger the COVs of thermal boundaries and soil properties,the deeper the SD of permafrost table;the longer the ACD of soil properties,the shallower the SD of permafrost *** study can provide a reference for the stability analysis of geotechnical engineering on the QTP considering the uncertainties of thermal boundaries and soil properties.

关键词： Frozen soil Spatial variability Thermal boundary Soil properties Probabilistic permafrost table

Fine-Grained Classification of Remote Sensing Ship Images Based on Improved VAN

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Computers, Materials & Continua 2023年第11期77卷 1985-2007页

作者： guoqing zhou Liang Huang Qiao Sun College of Electronic Engineering Naval University of EngineeringWuhan430033China

The remote sensing ships’fine-grained classification technology makes it possible to identify certain ship types in remote sensing images,and it has broad application prospects in civil and military ***,the current model does not examine the properties of ship targets in remote sensing images with mixed multi-granularity features and a complicated *** is still an opportunity for future enhancement of the classification *** solve the challenges brought by the above characteristics,this paper proposes a Metaformer and Residual fusion network based on Visual Attention Network(VAN-MR)for fine-grained classification *** the complex background of remote sensing images,the VAN-MR model adopts the parallel structure of large kernel attention and spatial attention to enhance the model’s feature extraction ability of interest targets and improve the classification performance of remote sensing ship *** the problem of multi-grained feature mixing in remote sensing images,the VAN-MR model uses a Metaformer structure and a parallel network of residual modules to extract ship *** parallel network has different depths,considering both high-level and lowlevel semantic *** model achieves better classification performance in remote sensing ship images with multi-granularity ***,the model achieves 88.73%and 94.56%accuracy on the public fine-grained ship collection-23(FGSC-23)and FGSCR-42 datasets,respectively,while the parameter size is only 53.47 M,the floating point operations is 9.9 *** experimental results show that the classification effect of VAN-MR is superior to that of traditional CNNs model and visual model with Transformer structure under the same parameter quantity.

关键词： Fine-grained classification metaformer remote sensing residual ship image

An analytical study of unsteady heat transfer in the rock surrounding a deep airway

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International Journal of Mining Science and Technology 2012年第3期22卷 411-415页

作者： Wang Yijiang zhou guoqing Wu Lei zhou Yang Lu Yong School of Mechanics & Civil Engineering China University of Mining & Technology Xuzhou 221116 China State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining & Technology Xuzhou 221008China

The heat transfer between an airway and the air flowing though it is an unsteady problem. The governing equation of unsteady heat transfer was solved using the method of separation of variables. The solution is an infinite series including Bessel functions. The theoretical solution was analyzed by solving for the positive roots of the transcendental equation by iteration. The dimensionless surface temperature of the sur- rounding rock is only affected by the Bi number but not by the thermo-physical coefficients of the rock. The dimensionless coefficient of heat transfer, k, decreases with the Fo number similarly to the influence of the Bi number on k. A formula for determining the fully developed stage (FDS) suitable for unsteady heat transfer in the airway is proposed. The FDS from theoretical analysis occurs with Fo from 1.6 to 2. The ratio of excess temperature in the surrounding rock is independent of the initial conditions and only dependent on the Bi number and the relative position in the airway, at the FDS. The calculation error is large when using just the first term from the complete series when Fo is from 2 to 12. Five terms give a solution approximately equal to that found using the complete series. The first term could replace the complete series only when Fo is greater than 12. The FDS plays an important role in predication of the temperature field of the surrounding rock and in simplified calculations.

关键词： Deep airway Surrounding rock Unsteady heat transfer Fully developed stage

Empirical formulae for electric double-layer repulsion between two arbitrarily inclined clay particles

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第6期10卷 1183-1189页

作者： Xiangyu Shang Juming Lu Lianfei Kuang Chen Yang guoqing zhou State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology School of Mechanics and Civil Engineering China University of Mining and Technology China Railway Engineering Equipment Group Co. Ltd.

To understand the mesoscopic mechanism of clayey soil in view of macroscopic behavior, it is essential to quantitatively calculate the electric double-layer repulsion between arbitrarily inclined clay ***, suitable calculation methods with high efficiency and accuracy are still rare at present in literature. Based on a great number of numerical calculations of the repulsion between two inclined platy clay particles, explicit empirical formulae for estimating electric double-layer repulsion between clay particles are put forward. Comparison between the empirical solutions and corresponding numerical results shows that the proposed formulae have a reasonable accuracy, and application of the presented formula is easy and efficient.

关键词： Clay particles Electric double-layer repulsion Numerical analysis Empirical formula

Coefficient of earth pressure at rest for normal,consolidated soils

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Mining Science and Technology 2010年第3期20卷 406-410页

作者： ZHAO Xiaodong zhou guoqing TIAN Qiuhong KUANG Lianfei State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining & Technology Xuzhou 221008 China School of Architecture & Civil Engineering China University of Mining & Technology Xuzhou 221008 China Jiuzhou College of Vocation & Technology Xuzhou 221116 China

In this study consecutive consolidated isotropically drained triaxial tests for the coefficient of earth pressure at rest(K_0) were carried out to investigate its rules of evolution as well as its strength characteristics for normal,consolidated saturated silt under high *** tests results indicate that:1) for normal,consolidated saturated silt,K_0 values increase as the consolidation stress increases at high pressure levels,while the nonlinear characteristics of K_0 are inconspicuous compared to cohesive soils;2) the Jaky and Roscoe equations,used to calculate K_0,are only suitable for certain soils,but cannot represent these values for normal, consolidated saturated silt due to the variation in bilinear strength at high pressure;and 3) there are close relations between the nonlinear characteristics of K_0 and the void ratio,measured in the *** share the same functional form while under pressure. Based on our experimental results,we developed an empirical linear model to interpret the rules of nonlinear variation for the coefficient of earth pressure at rest.

关键词： normal consolidated soils high pressure coefficient of earth pressure at rest nonlinear void ratio