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Copyright of Acta Scientiarum Naturalium Universitatis Sunyatseni / Zhongshan Daxue Xuebao is the property of Sun-Yat-Sen University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Smart Rail Transit is the property of Smart Rail Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Xi'an Jiaotong University is the property of Editorial Office of Journal of Xi'an Jiaotong University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The problem of tailplane stall after aircraft icing( ice-contaminated tailplane stall) has posed a serious threat to flight safety. In order to research on the sensitivity of ice-contaminated tailplane stall thoroughly and establish an optimized flight test state matrix, flow field display technology has been applied for the first time in China to ice-contaminated tailplane stall flight test of an aircraft. Based on the flow field characteristics and load response during flight test, the tailplane stall characteristics and stall margin of the aircraft were studied. In addition, the tailplane stall characteristics of the aircraft with different ice types, flap defections and center of gravity were analyzed, and an optimized flight test state matrix was established. The results indicate that using flow field display technology can intuitively and effectively determine the sensitivity of ice-contaminated tailplane stall and the critical flight test state,which is of great significance for optimizing aircraft aerodynamic design and improving flight test efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Propagation of shock waves generated by explosions is one of the important research topics in safety engineering. Thus, shock wave attenuation using filters has been investigated. In this study, the flow in the vicinity of a filter installed in air and water was visualized by the Schlieren method using a shock tube with a square section. In air, the shock wave was weakened by the filter. However, the filter was greatly deformed by the flow behind the shock wave. In water, no shock wave propagated behind the filter. Slight deformation was noted on the filter in water due to the flow that passed through the filter. Moreover, the flow speed behind the filter was suppressed as the number of cells in the filter was increased. [ABSTRACT FROM AUTHOR]

AIM: To investigate the mechanism of DL-buthionine-(S, R)-sulfoximine (DL-BSO) leading to ferroptosis of colon cancer cells. METHODS: (1) Human colon cancer HCT-116 and SW480 cells were treated with different concentrations of DL-BSO, and the cell viability was detected by CCK-8 assay. (2) The cells were treated with DL-BSO at experimental concentration, and divided into control group and DL-BSO group. The cell migration ability was detected by Transwell and scratch assays, and the expression levels of the target proteins were detected by Western blot. (3) The cells were pretreated with necrostatin-1(Nec-1) or ferrostatin-1(Fer-1), intervened with DL-BSO at experimental concentration, and divided into control group, DL-BSO group, inhibitor group and DL-BSO combined inhibitor group. The cell viability was detected by CCK-8 assay, and the iron ion concentration was detected by colorimetry. The gluthione (GSH) level was determined by commercially available kits, and the glutathione peroxidase 4(GPX4) and cystine/glutamate antiporter (xCT) expression levels were detected by Western blot. The level of reactive oxygen species (ROS) was detected by lipid peroxidation sensor C11-BODIPY-591 fluorescence visualization and flow cytometry. RESULTS: After DL-BSO intervention, cell viability was significantly reduced, and the optimal concentration and treatment time of DL-BSO were measured at 300 µmol/L and 36 h, respectively. Cell lateral and longitudinal migration ability was also reduced. The expression of GPX4 and xCT, key proteins of ferroptosis, was down-regulated. The ROS level and iron ion concentration were increased, and GSH concentration was decreased. The effects of DL-BSO were counteracted by Fer-1 rather than Nec-1. CONCLUSION: Treatment with DL-BSO causes death of colon cancer cells through the ferroptosis pathway and diminish their invasion and migration ability. [ABSTRACT FROM AUTHOR]

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gas-liquid two-phase flow is a very complicated flow phenomenon that involves the interaction between gas and liquid phases. Recently, an accurate simulation technique of two-phase flow has been developed. However, the validation of the simulated results is insufficient due to less experimental data. It is especially difficult to measure interfacial behavior with significant spatio-temporal fluctuation. To understand such phenomena, measurement methods with high spatial and temporal resolutions are required. Neutron imaging is a powerful tool for two-phase flow visualization. It can be applied to flow measurement in an opaque channel and has applicability to the heated condition. In this study, two-phase flow in the narrow rectangular channel was visualized by high-speed neutron imaging. The dynamics of the interfacial structure of air-water flow were investigated from the neutron transmission images, and the liquid film behavior was observed qualitatively. [ABSTRACT FROM AUTHOR]

Flow visualization is an important branch of scientific computational visualization.It mainly visualizes the simulation calculation results of computational fluid dynamics,and provides researchers with visually intuitive graphical images to facilitate researchers' analysis.The known techniques for flow visualization include geometric-based methods:such as streamline,particle tracking methods;and texture-based methods:LIC,spot noise and IBFV.Streamline visualization is an important and commonly used geometric visualization method for flow field visualization.In the study of streamline visualization,the placement of streamline is the focus of the entire streamline visualization,and the number and position of streamline affect the entire visualization effect.When too many streamlines are placed,it will cause visual clutter,and too little cause the flow field information to be incompletely expressed and cannot be transmitted to domain experts.In order to achieve accurate display of scientific data,streamline visualization has generated two important research directions:placement of seed points and reduction of streamline.This article introduces the related research of seed point placement method and streamline reduction method,summarizes some problems and solutions adopted in 2D and 3D flow fields,and proposes the need for streamline visualization in view of the growing scientific data in the future.

Fertilization equipment is one of the important components of low-pressure irrigation systems. A Venturi injector is widely used in the agricultural irrigation system, due to its simple structure, low price, and convenient use. The non-axisymmetric Venturi injector normally presents a better fertilizer absorption performance than the axisymmetric one. There are many studies on the response relationship between the fertilizer absorption performance and structural parameters of the Venturi injector. But, only a few studies are focused on the response relationship between the vortex characteristics and structural parameters. Therefore, this study aims to explore the influence mechanism of vortex on the non-axisymmetric Venturi injector in the low-pressure irrigation system, in order to improve the fertilizer absorption performance. An analysis was made to compare the vortex characteristics, fertilizer absorption performance, and the response relationship between fertilizer absorption performance and vortex characteristics of non-axisymmetric Venturi injectors with arc diffusion section and non-axisymmetric Venturi injectors with linear diffusion section. A test platform was developed to evaluate the fertilizer absorption performance. The fertilizer inlet of the non-axisymmetric Venturi injector was set as the atmospheric pressure, where the outlet was 0.04 MPa, and the water inlet was controlled between 0.07 and 0.25 MPa. A pressure gradient was taken for each 0.02 MPa to carry out the experimental test of fertilizer absorption performance. At the same time, the computational fluid dynamics software was selected to carry out the vortex analysis and visualization of the flow field. The mathematical modeling, meshing and simulation of Venturi injectors were carried out to compare with the physical test. The Tecplot post-processing software was used to analyze the numerical simulation, where the spline curve was used to locate the vortex. The results show that the diffusion section of the non-axisymmetric Venturi injector as an arc structure was conducive to reducing the vortex area, and the local energy loss in the vortex area, in order to improve the energy conversion efficiency of the non-axisymmetric Venturi injector. The vortex area and intensity decreased by 28.41%-42.37%, and 6.64%-35.65%, respectively, in the non-axisymmetric Venturi injector with the arc diffusion section under the same difference between inlet and outlet pressure. Once the outlet pressure was 0.04 MPa, the rate of fertilizer absorbed by the non-axisymmetric Venturi injector with the linear diffusion section increased gradually with the increase of inlet and outlet pressure difference, and finally tended to be stable. However, when the non-axisymmetric Venturi injector with the arc diffusion reached the maximum amount of fertilizer absorption, the amount of fertilizer absorption decreased with the increase of inlet and outlet pressure difference. The non-axisymmetric Venturi injector with the arc diffusion section presented a 50.64%-103.22% and 48.15%-98.25% increase in the amount and efficiency of fertilizer absorption, respectively, compared with the linear diffusion section. There was a gradually reduced increase in the amount of fertilizer absorption and its efficiency with the increase of the inlet and outlet pressure difference. The vortex region presented a significant effect on the fertilizer absorption performance of the non-axisymmetric Venturi injector (P≤0.05). The center point of the vortex region was gradually downward and backward with the increase of inlet and outlet pressure difference. When the inlet and outlet pressure difference was 0.03 MPa, the distance between the vortex boundary and the throat of the non-axisymmetric Venturi injector with the linear diffusion section was 0, indicating that the direct impact of the vortex on the formation of negative pressure in the throat. The vortex in the non-axisymmetric Venturi injector in the arc diffusion section was far away from the throat, without a direct effect on the formation of negative pressure in the throat. However, there was a gradually decreased distance between the vortex boundary and the throat of the non-axisymmetric Venturi injector in the arc diffusion section. The influence of the vortex on the throat increased gradually with the increase of the inlet and outlet pressure difference. A decrease in the area or intensity of the vortex area and an increase in the distance from the vortex boundary to the throat can greatly contribute to the better performance of fertilizer absorption in the non-axisymmetric Venturi injector. The finding can provide a strong reference for the structural design of non-axisymmetric Venturi injectors. [ABSTRACT FROM AUTHOR]

This paper focuses on the consistency of the logistics characteristics of a plateau railway and BIM-GIS technology in logistics system design and key data, and discusses the realization of intelligent logistics management system architecture. By using the method of comparative analysis, this paper summarizes the characteristics and applications of BIM and GIS technology, and analyzes the advantages of BIM-GIS collaborative integration application in the field of plateau railway logistics. Based on the analysis of the logistics characteristics of a plateau railway and logistics coordination model, this paper proposes a systematic concept for logistics from visualization to information flow and monitoring integration. Through system thinking method, the logistics execution system, warehouse management system, logistics integrated information system, key data module of the Internet of Things data value center are created. On this basis, the network architecture and software architecture of the logistics system are realized, and the feasibility of the development of plateau railway logistics management system based on BIM-GIS technology is demonstrated. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Nail breakage of proximal femoral nail anti-rotation is one of the severe implant failure that must be revised. At present, the biomechanical causes for the nail breakage are mostly inferred from metal fatigue; however, there is still no direct research or method to prove the mechanical mechanism of nail breakage. Therefore, to construct a finite element model of proximal femoral nail anti-rotation in treating intertrochanteric fracture and to realize the visualization of nail breakage are of great significance in studying the failure mechanism. OBJECTIVE: To simulate biomechanical process of the nail breakage of proximal femoral nail anti-rotation in treating intertrochanteric fracture. METHODS: Femoral CT data of a hip fracture patient, who was hospitalized in Department of Traumatic Orthopedics, First Affiliated Hospital of Guangzhou University of Chinese Medicine, were imported into Mimics 19.0 and polished in Geomagic Studio software to reconstruct a three-dimensional finite element model of proximal femur. The proximal femoral nail anti-rotation model was created in SolidWorks based on the specification and matched with the polished femoral model according to the surgical protocol. The proximal femoral nail anti-rotation intramedullary nail was fixed to the proximal femur, and the assembly model of the femur and proximal femoral nail anti-rotation intramedullary nail was established. The component including proximal femoral nail anti-rotation and proximal femur was meshed as tetrahedron and constructed as AO-31A1.3 type fracture (2018 version) in Hypermesh software. After material contents (including critical fatigue parameter of implants and biomechanical material parameter of femur), loading, boundary condition and friction coefficient were completed, the K file was finally solved in LS-DYNA. RESULTS AND CONCLUSION: (1) Crack first appeared on the weakness on the blade hole of nail. (2) The maximal Von Mises stress of nail reached 412 MPa before breakage. During the crack propagation, stress concentrated at the intersection between nail and helical blade, locking bolt and nail. Stress distributed around the head-neck part and the insertion point of the great trochanter on femur. The maximal Von Mises stress of femur during the nail breakage was 248.3 MPa. (3) The tip of helical blade and the femoral head varus in the coronal plane, and being the most displaced parts. (4) The validation results suggest that this model can effectively simulate the nail breakage of proximal femoral nail anti-rotation in treating intertrochanteric fracture. The weak part of nail was the critical area of stress concentration and destruction. [ABSTRACT FROM AUTHOR]

High speed helicopter with coaxial rigid rotor is one of the most promising configurations for the next generation helicopter. Wind tunnel experiment is an important way in helicopter aerodynamics research and in the development of a new helicopter. The current status of wind tunnel tests on coaxial rigid rotor is examined in this paper. A brief history of the developed test facilities is given. The review is followed by the research results on different aerodynamic problems, e.g., lift offset, flow field visualization and measurement, drag reduction of hub, propeller and fuselage test. Considering the characteristics of previous studies, the prospects of wind tunnel experiment for coaxial rigid rotor on test rig development, research capability improvement, and test results application are presented. [ABSTRACT FROM AUTHOR]

The traditional visualization pipeline of cloud-motion wind(CMW) has considerable computational redundancy.This paper proposed a fast wind visualization pipeline,which could directly generate a vivid large-scale wind situation video for human eyes from any raw satellite image sequence.Guiding by sparse pixel block-matching for cloud motion estimation in satellite image sequence,the proposed algorithm warped and blended multi-frame noised textures by a warping mesh derived from the matching results.Without any complicated optical flow calculation and additional flow visualization post-processing,this compact visualization pipeline was more convenient in programming and less dependent on computing hardware.Experimental results show that the proposed straightforward algorithm can generate an easily identifiable and time-consistent dynamic visualization video of CMW directly from infrared,visible or water vapor satellite data.It is also more robust to the irregular dissipation and generation of cloud. [ABSTRACT FROM AUTHOR]

The nanosecond pulsed plasma discharge actuator is used on a flying wing aircraft. At the angles of attack rang from -4° to 28°, the impact of plasma actuator arrangement position and discharge frequency on lift-enhancement effect is tested. Oil flow visualization is used to investigate the surface flow pattern varies with angles of attack for the plasma actuator turned on and off. The result indicates that lift-enhancement can be achieved through the actuator discharges at large angles of attack on flying wing aircraft. The arrangement position and discharge frequency both have a significant impact on lift-enhancement effect. The actuator which arranged at the leading edge of the aircraft could get the best lift-enhancement effect. There exists an optimal discharge frequency, flow separation under this frequency can be effectively suppressed, which results the best lift-enhancement effect. The flow visualization test shows that the control mechanisms of the plasma actuator are to inject energy to the shear layer, thus increased the vortex strength. The vortices strengthen the mixing of the outer high-speed fluid with inner low-speed fluid, which effectively restrains the separation.

Aiming at the problems that the flow field visualization algorithm existed the referential ambiguity of vector movement and lack of the distinction between vector field rate, this paper proposed an improved line integral convolution algorithm based on multi-frequency sparse noise texture to improve the information expression effect of flow field visualization. Firstly, the method divided the noise groups with different frequencies according to the magnitude of the vector field rate order, and synthesized the specific multi-frequency noise texture suitable for the vector field. Then, it used a slope convolution kernel to convolve the noise textures from vector field streamlines. Finally, it generated a color image with both direction and rate information of vector field motion. The experimental results show that this method can enhance the user' s perception of flow field size and vector field direction, and has achieved good visualization results in large-scale wind field data visualization verification experiments. [ABSTRACT FROM AUTHOR]

To address the problem of insufficient depth information and unnatural interaction by using the current flow visualization application in two dimensional environment, a flow visualization method based on immersive augmented reality is proposed. This method displays the characteristics of flow field changes in the real space through streamlines, uses the immersive augmented reality technology to provide users with effective depth information, and arranges the streamlines through natural interaction methods such as gestures and gaze. And the method uses the Server/Client architecture, in which the server is used for streamline computing and the head-set augmented reality device is used for streamline registration, result display and user interaction. Finally, an original system is developed based on the method. The streamline placement method based on user gaze and the seed placement method based on user gaze and gesture are designed. The interaction methods take advantage of the natural interaction to improve the user’s efficiency in streamline arrangement and data analysis. The results indicate that the method can accurately complete the streamline rendering in immersive augmented reality environment, reflect the change of the flow field and provide users with natural interaction. [ABSTRACT FROM AUTHOR]

In this paper, three key issues concerning the safety of the liquefied gas storage were discussed in terms of the thermo-hydro-solid coupling response of the solid materials and the medium in the liquefied gas storage tank after the thermal invasion. Combined with the visualization experiment and the numerical simulation of the thermo-hydro-solid coupling response: the layered instability circulation mode during the roll over process of the medium in the tank, the local high temperature distribution characteristics and cracking behavior of the tank, as well as the two-phase flow expansion injection and the dynamic pressure response law of the tank top are analyzed. It is found that the mechanism of stratification instability is closely related to the initial buoyancy ratio, the temperature distribution in the high temperature region of the tank top affects the cracking form of the tank, and the explosion boiling process after the cracking of the tank presents the characteristics of intermittent expansion of two-phase flow. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Steam Injector (SI) has capability to be applied to heat pump systems and to have downsized them. A SI works as passive jet pump and heat exchanger without external power sources. It has high heat-transfer performance due to direct contact condensation between steam flow and subcooled water jet. The objective of the present study is to clarify thermal hydraulics characteristics and operating criteria for an Ultra-Micro Steam Injector. To this end, SI with throat diameter of 2.0 mm was designed and investigated experimentally. Visualization of internal flow behavior and measurement of pressure and temperature were conducted. As a result, we confirmed that the formation of the water jet, the stop of drainage from the drain port and the increase of discharge pressure. The internal flow patterns were classified into four types and considering the energy balance of water and steam. One of the operating criteria was clarified that water could completely condense the steam. The discharge pressure was increased up to 2 times at maximum. There is possibility the operating criteria can be predicted from the position where the flow behavior changes. [ABSTRACT FROM AUTHOR]

Aiming at enriching teaching contents and experimental teaching methods of fluid dynamics course, several classical problems in fluid mechanics have been simulated using LBM (Lattice Boltzmann method). An integrated virtual simulation experiment platform encapsulated by Matlab GUI (Graphic User Interface) is developed to improve traditional teaching mode and teaching efficiency. Three modules, lid-driven flow module, Poiseuille flow module and Karman vortex street module, are included in this platform. The simulation results can be displayed directly by inputting operating parameters on the user interface of the platform. Compared with the traditional teaching mode and experiment, this integrated virtual simulation experiment platform has the advantages of good visualization, fast calculation speed, clear user interface, simple operation, low teaching cost and easy communication, which is beneficial to the understanding of the students on the abstract concepts and complex flow patterns in fluid dynamics course. Owing to the increase in the interest of the students and the efficiency of classroom teaching, this platform deserves to be popularized in the teaching of fluid mechanics. [ABSTRACT FROM AUTHOR]

Supersonic cooling gas film is a key technique applied to hypersonic imaging guided vehicle. For raiio of static pressure (RSP) is a major factor affecting the development of supersonic cooling film, it has great engineering significance to carry out a systematic research on the RSP. In this view, flow visualization tesis of supersonic cooling film at different RSP levels based on nano-traccr planar laser scattering (NPLS) were carried out in a M6 hypersonic wind tunnel. Through the analysis of transient flow visualization images, the development process of the shear layer between the hypersonic mainstream and supersonic jet was studied. With the analysis of fractal dimension and intermitiency, the distributions were, respectively, obtained of fractal dimension aloiltf the flow direction and intermittency factor fllonfi the normal direction, and ihe effect of RSP on turbulence rifivrlopmenl was analyzed. The evolution of supersonic 289 flow field mainly includes four slaves which ran he characterised by laminar shear layer. disturbance occurrence, mixing ol "mainstream jet" shear layer and jet boundary layer, and formation of glarge boundary layer". RSP has obvious influence on the wave structures, the film thickness and the turbulence degree of the flow field. The overall thickness of lbe gas film is positively related lo the .sialic pressure ratio along with the "condense" for a under-mntch RSP and the "inflation" tor n ovcf-mxirli RSP. The film thickness of under-march ntAtn and tnakii slate increases slow first but then fast, meanwhile it is just opposite under over-match state. The turbulence breaking factor of undcr-prcssurc state and match state is generally smnllcr than that of tin: overpressure Matt in the forepart of flow field, bul il increases rapidly along the flow direction. Moreover, the match slate has the largest turbulence breaking Factor and ihe highest degree of turbulence level compared with the other states. [ABSTRACT FROM AUTHOR]

Effective seeding method is the key to influence the streamline distribution and to understand the underlying properties of flow field. Based on the accurate description of flow field variation and important features, this paper proposes two information entropy-based seeding methods to solve the well-known occlusion and cluttering issue. The first greedy seeding method locates interesting areas through the calculation of entropy values. The greedy seeding method is highly sensitive to the important features. The second Monte Carlo seeding method generates random inputs based on a probability distribution, and then defines the influence areas of input grid points as a circle in 2D and a sphere in 3D. Comprehensive experiments on multiple datasets show that the greedy seeding method can capture the important features efficiently and the Monte Carlo seeding method shows significant ability to obtain global variation. Besides，the combination of both methods can get more optimal flow field visualization. [ABSTRACT FROM AUTHOR]

To study wing-body rock of canard-configuration aircrafts, a model for wind tunnel test was designed having a chine forebody, canard wings, strake wings, main wings, and a vertical fin. This model was tested by different methods including free rolling motion, static force balance test, dynamic derivative test, and smoke wire technique. First, the complete rock process was studied by free-to-roll experiment in the range of pitch angel θ=12°~52° and Δ=1°. The results show that, rolling motions of the canard-configuration aircraft have several different mean roll angles and motion forms vary with different pitch angles. Second, the results of the static force balance test and dynamic derivative test confirm that the rolling motion can occur around zero or nonzero equilibrium roll angles with limit-cycle forms or nolimit cycle ones due to the influence of multi-vortex structures. Finally, the flow visualization tests show that the main vortices generate the wing-body rock at different stages. The possible mechanism for the wing-body rock was also analyzed for the canard-configuration aircraft. [ABSTRACT FROM AUTHOR]

In the present study, 2 bionic functional surfaces mimicking from shark skin and dolphin skin respectively were designed and constructed. The simplified riblet mimicking from shark skin was sculptured on the cast iron, and such model was called Model 1 in this study. The riblet was controlled by 3 parameters: the depth of riblet, the aspect ratio and the spacing of riblet. The Model 2 was designed on the basis of Model 1. A layer of elastic material was coated on the Model 1, and this kind of bionic surface was called Model 2. The 200 QJ50-26 type centrifugal pump which was produced by Jilin Aojitong Pump Company, Limited was selected as the implementation carrier of the 2 bionic models, and the study on pump efficiency enhancement by above 2 models was performed in the present paper. There were 3 groups of pumps selected in the experiment. The samples 1 and 2 were the pumps whose impeller surface adopted Model 1, the samples 3 and 4 adopted Model 2 on the pumps impeller, and the sample 5 was a pump with ordinary impeller. The experimental results showed that compared to the sample 5, the pump efficiency of the samples 1, 2, 3 and 4 was all improved effectively in the effective working flow range. The pump efficiency of the samples 1 and 2 was increased by 2%-3%, and the samples 3 and 4 by about 5%. However, the difference was that for the samples 1 and 2, the pump efficiency was enhanced only during the effective working flow range (40-60 m3/h), while the pump efficiency of the samples 3 and 4 was increased in all the flow range from 0-60 m3/h. Above experimental results indicated that the efficiency enhancement effect of the pump mimicking from dolphin skin was obvious. According to the structure of Model 1 and 2, 2 experimental samples were designed and prepared in the flow visualization test, which was performed at the flow speed of 5 cm/s and water temperature of 20℃. The experimental results showed that the distance between wake attachment point and tail for Model 2 was shorter than that for Model 1, which indicated that the negative pressure of Model 2 was lower than that of Model 1. That was to say, the pressure drag of Model 2 was smaller than that of Model 1. In addition, during the experiment, the surface elastic deformation of Model 2 produced by the flow pressure was clearly observed. Furthermore, it was found that the wake vortex spacing of Model 2 was shorter than that of Model 1, which indicated that the wake vortex of Model 1 was generated frequently, and the energy dissipation was higher than that of Model 2. The drag reduction effect of Model 2 was better than that of Model 1. Therefore, the pump efficiency enhancement effect of Model 2 is more effective than Model 1, that is to say, the bionic functional surface mimicking from dolphin skin structure is more effective to improve pump efficiency. The reasons to pump efficiency improvement are that the elastic deformation of surface material which is coupling with the bionic structure together can control fluid medium effectively, inhibit the spread and development of fluid medium disturbance, and reduce the vortex generation density and speed. So, the dissipation of energy is reduced and the drag reduction is achieved. [ABSTRACT FROM AUTHOR]

Videogrammetric measurement (VM) becomes a focus technique at home and abroad because of its no special requirements on the test model and its non-contact way for wind tunnel testing. VM techniques and their applications for wind tunnel testing in highly developed institutes abroad are firstly introduced in detail, and some problems about the VM used in high speed intermittent wind tunnels at home are analyzed. Dynamic calibration for multi-cameras and sequential images matching technique for the mark points based on motion evaluation are developed in CARDC in order to achieve the high precision pose measurement in noise (about 130dB)/vibration environment. The potential application prospects of VM have been demonstrated by several preliminary testing cases in a 2 meter supersonic tunnel tests and a 2.4 meter transonic tunnel, including angles of attack and sideslip measurement of test model, deformation of full size embedded door and a static aero-elastic test model, which shows the precision of VM is high. On the other hand, VM can be used to determine the optical path difference (OPD) by measuring the deviation displacement field induced by the beams from center of camera to the background points crossing the flow field, provides a new way to research and measure aero-optic effects and flow display at the surface of the testing model, which is simple and needs no expensive coherent sources. [ABSTRACT FROM AUTHOR]

The flow characteristics across different flow regions, engineering requires for aerodynamic force/heating predicting technique, and the research status in China and foreign countries are summarized. To solve the main problems of aerodynamic force/heating predicting techniques across different flow regions, some recent developments, such as the similarity criterion for experimental simulation based on viscous interaction and Knudsen number, framework optimization of microbalance as well as aerodynamic force measurement technique, the measurement of the middle and low heat transfer using infrared mapping, flow visualization and measurement, together with N-S/DSMC hybrid numerical method, have been presented, and further investigation is suggested. [ABSTRACT FROM AUTHOR]

The particle tracking velocimetry (PTV) algorithm based on Delaunay Tessellation (D T ), named as 3DT PTV is improved to match particles from two consecutive instants in the three-dimensional field. In 3DT P TV, the particle pairing is summarized out of the pattern pairing, in which a pattern DT grid is adopted in the selection of pattern candidate to enable 3DT PTV free of parameters and applicable in unevenly distributed flow, and a pattern identifying vector is proposed for the pattern similarity judgment. The result of particle pairing is then doubled and refreshed by the processors of "Dual Computation" and "Selection by Probability". 3DT PTV is tested by standard synthetic flows with self-defined perturbations. The merit of 3DT PTV confirmed by the test result is the high accuracy in addressing complex flow with noticeable ratio of particles having no pair. [ABSTRACT FROM AUTHOR]

The flow around cylinder is one of the classic research issues of fluid mechanics. The modification of the cylindrical geometry will affect the cylinder's pressure distribution and near wake flow structures. The present study on slotted cylinder has some certain values in engineering applications such as vortex generator in flow meters and heat convection. Large eddy stimulation based on 3-D Fluent code was carried out for cylinders with slit, with respect to test model of ratio of slit width to diameter s /d= 0. 15 on five different Reynolds numbers (Re = 1500,3000,44005837,7200). By the means of qualitative flow visualization and quantitative PIV experiments, the flow patterns between the slit and the shedding vortex of the baseline and slotted cylinder were carefully investigated, measuring and predicting of the shedding vortex frequency were included. The results of numerical simulation agreed well with the experimental measurement. The experimental and computational results show that the flow in the slit demonstrated periodic motion, this oscillating vent-flow has greatly altered the near wake flow features. The periodic oscillation in the slit has enhanced the periodicity of the flow around circular cylinder; consequently, the slotted cylinder exhibited an increase in shedding vortex frequency and Strouhal number compared with their baseline case at the same Reynolds numbers. Meanwhile, The wake of the slotted cylinder presented obvious three dimensional features. [ABSTRACT FROM AUTHOR]

The unsteady characteristics of ventilated cavitating flows around axisymmetric body with a cavitator are addressed by using experimental methods. Cavities around the body are observed by means of a high-speed video camera in the different conditions. The results show that the shapes of the cavities increase with the increase in ventilation rate at the same Froude number, and they develops from the free cavities to the supercavities. In the supercavitating flow stage, a smooth and clear interface exists between main stream and supercavitating region. The cavity shapes decrease with the increase in Froude number at the same ventilation rate. The ventilated air doesn't form a big bubble because the air flows to downstream of flow field with the high speed flow. The unsteady characteristics can be observed in ventilated cavitating now field. The velocity of re-entrant jet increases with the increase in ventilation rate. [ABSTRACT FROM AUTHOR]

Based on measured velocities in conical vortices by flow visualization, a simplified two-dimensional vortex model was established by adding transitional region between the vortex core and the potential flow region of the Rankine vortex. Through this flow model, a relationship between the flow above the vortices, the curvature radius of flow streamlines in the vortices and the suctions beneath vortex cores was given. The flow model indicats that the larger the curvature of flow streamlines and the faster the vortex spins, the greater the intensity of vortex is. The effect of rational velocity on intensity of vortices is more obvious. Through measured velocities by flow visualization and parameters of vortices, the intensities of conical vortices on a large-span fiat roof under different wind directions were provided. The quasi-steady theory was corrected by including the effect of vortices. With this two-dimensional vortex model and the corrected quasi-steady theory, mean and peak suctions beneath cores of conical vortices can be predicted, which were verified by measured pressures on a larger-scale model of the large-span fiat roof. [ABSTRACT FROM AUTHOR]

Using PIV (particle image velocimetry) and schliren technique, the characteristic of interface, specially growth rate of turbulent kinetic energy, between free stream and compressible mixing layer at convective Mach number Mc=0. 38 has been investigated. The results show that the increase or decrease of turbulent kinetic energy mainly derivates from the compressibility of fluid particle near the interface. The work resulting from streamwise linear strain of averaged velocity plays an important role of turbulent kinetic energy near the interface. It seems that the existence of large-scale structure suppresses the change of turbulent kinetic energy near the interface. [ABSTRACT FROM AUTHOR]

The heat transfer and flow field characteristics of a periodical turbulent jet impinging on a flat plate are experimental studied and the results as well as the mechanism of heat transfer enhancement are discussed. The periodical jets are produced by a special mass flow rate controller. The results of two typical periodical jets (i.e., sinusoidal and rectangular jets) are presented and the signal frequency is performed as a parameter in the experiments. The experimental results show that the heat transfer performances of two periodical jets with same average flow rate are obviously different. The rectangular jet, which has a step change in signal function itself, is much more effective for heat transfer improvement than the sinusoidal impinging jet. A higher frequency is promising in heat transfer for both signals. Particle Image Velocimetry (PIV) is used to measure the phase-locked flow field of the periodically impinging jet. For the higher frequency case of a rectangular impinging jet which has a step change in signal itself, the plate surface is exposed to both a strong impinging jet and a strong vortex during a periodical cycle and thereby it improves the convection process. In the flow field of a sinusoidal impinging jet, the phase-averaged velocity is lower than the case in a rectangular jet. The entrainment to the ambient fluid and the impingement as well as the vortex spreading are not so strong as that of a rectangular jet, thus it leads to only a slight heat transfer augmentation even at a higher frequency. [ABSTRACT FROM AUTHOR]

By via of PIV measurement technology, airflow speed and turbulent intensity on the process of powder jet were measured in verticle square tube. Further analysis and discussion were carried on based on the metrical data. Variation curve of the airflow speed and turbulence intensity with time were obtained through the computation. The results indicate that in tube average airflow speed has the linearity relation with time basically before the end of powder jet. After the end of powder jet, the average airflow speed reduces suddenly. Turbulence intensity in the horizontal direction and vertical direction decays with the negative exponent in 0 ~ 350 ms after the process of powder jet. The turbulence intensity has small variation with the time in the tube after 350 ms. [ABSTRACT FROM AUTHOR]

To investigate the effects of the flow field by the injection time and the medium status, particle image velocimetry(PIV) technique is used. The droplets induced by the former spray are used as tracer element in current spray. The experiments include the velocity measurement of different lime, injection pressure and the background density of the folw lied. A swirl forms around the tip of the spray during the course of injection and its intensity gorws up when the spray develops and the injection pressure increases. When the medium density increases, the penetration speed reduces and the relative speed increases. Thus the swirl caused by the spray is of benefit to the oil diffuseness, and increasing the injection pressure can intensify this effect. Increasing the medium density will make the drops denser and this will slow down the mixing speed of the oil and air. [ABSTRACT FROM AUTHOR]

The structure optimal design of hydraulic mechanical block (HMB) from the angle of characteristics, which is too difficult to solve for a long time, is presented. On the basis of computational fluid dynamic (CFD) method, the strategies dealing with grid and initial and boundary conditions from testing in HMB inner flow fields are given. Through the numerical simulation of typical duct in pipeline networks, flow status in orthogonal ducts was qualitatively analyzed, and the regulation that the pipeline configuration affected the flow-resistance was gained, which helped to provide improvements on the pipeline's geometry structure. The 3D simulation results of HMB indicate that CFD method can acquire the basic structure characteristics of flow field in pipeline networks and ideal pipeline layout scheme, which improves the optimal design quality with great accuracy. [ABSTRACT FROM AUTHOR]