期刊文献+
共找到22篇文章
< 1 2 >
每页显示 20 50 100
数字式测力表在水力测功器中的应用
1
作者 刘怀 张旺 《机械工程师》 北大核心 1995年第6期38-39,5,共3页
关键词 数字式测力表 水力测功器 内燃机车 应用
下载PDF
超重失重演示器
2
作者 安兵锡 《教学仪器与实验》 1996年第1期19-20,34,共3页
关键词 测力表 超重失重 牵引力调节器 升降机 演示器 失重现象 中心刻度 加速下降 牵引绳 摩擦力
下载PDF
Measuring the Internal Velocity of Debris Flows Using Impact Pressure Detecting in the Flume Experiment 被引量:12
3
作者 YANG Hongjuan WEI Fangqiang +4 位作者 HU Kaiheng Sergey CHERNOMORETS HONG Yong LI Xiaoyu XIE Tao 《Journal of Mountain Science》 SCIE CSCD 2011年第2期109-116,共8页
Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity ... Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity because of the destructive power of debris flow process. In this paper, we address this problem by using the relationship between velocity and kinetic pressure, as described by surface velocity and surface kinetic pressure data. Kinetic pressure is the difference of impact pressure and static pressure. The former is detected by force sensors installed in the flow direction at the sampling section. Observations show that static pressure can be computed using the formula for static water pressure by simply substituting water density for debris flow density. We describe the relationship between surface velocity and surface kinetic pressure using data from seven laboratory flume experiments. It is consistent with the relationship for single phase flow, which is the measurement principle of the Pitot tube. 展开更多
关键词 Internal velocity MEASUREMENT Debris flow Impact pressure
下载PDF
Non-complete relief method for measuring surface stresses in surrounding rocks 被引量:4
4
作者 张凤鹏 邱兆国 冯夏庭 《Journal of Central South University》 SCIE EI CAS 2014年第9期3665-3673,共9页
The measurement of surface stresses in surrounding rocks with the use of a relief method of annular hole-drilling was studied by numerical analysis. The stress relief process by hole-drilling was then simulated with t... The measurement of surface stresses in surrounding rocks with the use of a relief method of annular hole-drilling was studied by numerical analysis. The stress relief process by hole-drilling was then simulated with the use of finite element method. The influences of the borehole diameter(d), the initial stresses and the ratio of the initial principle stresses on the variations of the remained stress and the released stress in function of the relief depth(h) were discussed. The relation between the non-dimensional ratio of the released principle strains and that of the initial principle stresses, and the effect of the elastic modulus and the Poisson ratio of the rock mass on the stress relief curves were studied. The results show that the stress relief behavior formulated with the non-dimensional ratio of the released stress and the ratio of h/d is only sensitive to the ratio of the initial principle stresses and the Poisson ratio. The stresses are completely released when h equals 1.6d, and the tensile stresses take place on the bore core surface in the relief measurement process. Finally, a non-complete relief method of annular hole-drilling for measuring surface stress in surrounding rocks is proposed and the procedure is presented. 展开更多
关键词 non-complete relief method surface stress in surrounding rock stress relief rate ratio of initial principal stresses ratioof released principal strains
下载PDF
Seepage-stress coupling constitutive model of anisotropic soft rock 被引量:2
5
作者 张向霞 杨林德 闫小波 《Journal of Central South University》 SCIE EI CAS 2009年第1期149-153,共5页
To provide a seepage-stress coupling constitutive model that can directly describe the seepage-stress coupling relationship, a series of one-dimensional seepage-stress coupling tests on two kinds of soft rock (argilla... To provide a seepage-stress coupling constitutive model that can directly describe the seepage-stress coupling relationship, a series of one-dimensional seepage-stress coupling tests on two kinds of soft rock (argillaceous siltstone and brown mudstone) were performed by using an MTS-815.02 tri-axial rock mechanics test system, with which the stress-strain curves according to the seepage variation were obtained. Based on the experimental results and by employing Hooke's law, the formulation of the coefficient of strain-dependent permeability was presented and introduced to establish a coupling model. In addition, the mathematical expression and the incremental formulation for coupling model were advanced, in which five parameters that can be respectively determined by using the experimental results were included. The calculated results show that the proposed coupling model is capable of simulating the stress-strain relationship with considering the seepage-stress coupling in the nonlinear elastic stage of two kinds of soft rock. 展开更多
关键词 soft rock stress--strain relation seepage-stress coupling constitutive model coefficient of permeability
下载PDF
Influence of Road Wetness on Tire-Pavement Rolling Resistance
6
作者 Jerzy Ejsmont Leif Sjogren +1 位作者 Beata Swieczko-Zurek Grzegorz Ronowski 《Journal of Civil Engineering and Architecture》 2015年第11期1302-1310,共9页
Rolling resistance of tires is one of the most important factors influencing energy consumption of road vehicles, especially on rural roads. For practical reasons, most of rolling resistance measurements are usually p... Rolling resistance of tires is one of the most important factors influencing energy consumption of road vehicles, especially on rural roads. For practical reasons, most of rolling resistance measurements are usually performed for dry road conditions. Based on the fact that roads are wet during a considerable time over the year and as part of the projects MIR/AM, ROLRES and ROSANNE, the TUG (Technical University of Gdafisk) in Poland and VTI (Swedish National Road and Transport Research Institute) in Sweden carried out trailer rolling resistance measurements on wet road surfaces to investigate water film influence on rolling resistance on different pavements. A specially-designed trailer to measure rolling resistance has been used. The test sections were both rural roads and an abandoned airfield equipped with water film sensors mounted in the pavement. Results indicate strong influence of test speed and water film depth, as well as influence of surface texture. The increase of rolling resistance on wet surfaces is caused by both hydrodynamic phenomena and cooling effect of water that decreases tire temperature thus increasing rolling resistance. 展开更多
关键词 Tires rolling resistance road wetness water film
下载PDF
Exploring valid internal-control genes in Porphyra yezoensis(Bangiaceae) during stress response conditions 被引量:3
7
作者 王文磊 吴晓洁 +5 位作者 王超 贾兆君 何林文 韦一凡 牛建峰 王广策 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第4期783-791,共9页
To screen the stable expression genes related to the stress (strong light, dehydration and temperature shock) we applied Absolute real-time PCR technology to determine the transcription numbers of the selected test ... To screen the stable expression genes related to the stress (strong light, dehydration and temperature shock) we applied Absolute real-time PCR technology to determine the transcription numbers of the selected test genes in Porphyra yezoensis, which has been regarded as a potential model species responding the stress conditions in the intertidal. Absolute real-time PCR technology was applied to determine the transcription numbers of the selected test genes in Porphyra yezoensis, which has been regarded as a potential model species in stress responding. According to the results of photosynthesis parameters, we observed that Y(II) and Fv/Fm were significantly affected when stress was imposed on the thalli of Porphyra yezoensis, but underwent almost completely recovered under normal conditions, which were collected for the following experiments. Then three samples, which were treated with different grade stresses combined with salinity, irradiation and temperature, were collected. The transcription numbers of seven constitutive expression genes in above samples were determined after RNA extraction and cDNA synthesis. Finally, a general insight into the selection of internal control genes during stress response was obtained. We found that there were no obvious effects in terms of salinity stress (at salinity 90) on transcription of most genes used in the study. The 18S ribosomal RNA gene had the highest expression level, varying remarkably among different tested groups. RPS8 expression showed a high irregular variance between samples. GAPDH presented comparatively stable expression and could thus be selected as the internal control. EF-la showed stable expression during the series of multiple-stress tests. Our research provided available references for the selection of internal control genes for transcripts determination of P. yezoensis. 展开更多
关键词 constitutive expression gene housekeeping gene Porphyra yezoensis Ueda real-timequantitative PCR stress responding
下载PDF
Challenges of incorporating gene expression data to predict HCC prognosis in the age of systems biology 被引量:6
8
作者 Yan Du Guang-Wen Cao 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第30期3941-3944,共4页
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide.The recurrence of HCC after curative treatments is currently a major hurdle.Identification of subsets of patients with distinct progn... Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide.The recurrence of HCC after curative treatments is currently a major hurdle.Identification of subsets of patients with distinct prognosis provides an opportunity to tailor therapeutic approaches as well as to select the patients with specific sub-phenotypes for targeted therapy.Thus,the development of gene expression profiles to improve the prediction of HCC prognosis is important for HCC management.Although several gene signatures have been evaluated for the prediction of HCC prognosis,there is no consensus on the predictive power of these signatures.Using systematic approaches to evaluate these signatures and combine them with clinicopathologic information may provide more accurate prediction of HCC prognosis.Recently,Villanueva et al developed a composite prognostic model incorporating gene expression patterns in both tumor and adjacent tissues to predict HCC recurrence.In this commentary,we summarize the current progress in using gene signatures to predict HCC prognosis,and discuss the importance,existing issues and future research directions in this field. 展开更多
关键词 Gene expression signatures Hepatocellular carcinoma Prognosis
下载PDF
Bias-Corrected Short-Range Ensemble Forecasts for Near-Surface Variables during the Summer Season of 2010 in Northern China 被引量:2
9
作者 ZHU Jiang-Shan KONG Fan-You LEI Heng-Chi 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第4期334-339,共6页
A running mean bias (RMB) correction ap- proach was applied to the forecasts of near-surface variables in a seasonal short-range ensemble forecasting experiment with 57 consecutive cases during summer 2010 in the no... A running mean bias (RMB) correction ap- proach was applied to the forecasts of near-surface variables in a seasonal short-range ensemble forecasting experiment with 57 consecutive cases during summer 2010 in the northern China region. To determine a proper training window length for calculating RMB, window lengths from 2 to 20 days were evaluated, and 16 days was taken as an optimal window length, since it receives most of the benefit from extending the window length. The raw and 16-day RMB corrected ensembles were then evaluated for their ensemble mean forecast skills. The results show that the raw ensemble has obvious bias in all near-surface variables. The RMB correction can remove the bias reasonably well, and generate an unbiased ensemble. The bias correction not only reduces the ensemble mean forecast error, but also results in a better spreaderror relationship. Moreover, two methods for computing calibrated probabilistic forecast (PF) were also evaluated through the 57 case dates: 1) using the relative frequency from the RMB-eorrected ensemble; 2) computing the forecasting probabilities based on a historical rank histogram. The first method outperforms the second one, as it can improve both the reliability and the resolution of the PFs, while the second method only has a small effect on the reliability, indicating the necessity and importance of removing the systematic errors from the ensemble. 展开更多
关键词 short-range ensemble forecast bias-corrected ensemble forecast running mean bias correction near-surface variable forecast
下载PDF
Determination of Clarithromycin in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Validation and Application in Clinical Pharmacokinetic Study 被引量:7
10
作者 ZHANGXiang-rong CHENXiao-yan LIXiao-yan ZHONGDa-fang 《Journal of Chinese Pharmaceutical Sciences》 CAS 2004年第3期166-170,共5页
Aim To develop a liquid chromatographic-tandem mass spectrometric (LC-MS-MS)method to determine clarithromycin in human plasma. Methods The analyte and internal standardroxithromycin were extracted from plasma samples... Aim To develop a liquid chromatographic-tandem mass spectrometric (LC-MS-MS)method to determine clarithromycin in human plasma. Methods The analyte and internal standardroxithromycin were extracted from plasma samples by n-nexane-dichloromethane-isopropanol(300:150:15, V/V/V) and chromalographed on a C_(18) column. The mobile phase consisted ofmethanol-water-formic acid (80 = 20:1, V/V/V) . Detection was performed on a triple quadrupoletandem mass spectrometer via electrospray ionization source (ESI) in the positive mode. Results Themethod had a lower limit of quantification of 10.0 ng·mL^(-1) when 0.2 mL plasma was used. Thelinear calibration curves were obtained in the concentration range of 10.0 - 5000 ng·mL^(-1) . Theintra- and inter-run precisions were lower than 3.3% in terms of relative standard deviation (RSD),and the accuracy ranged +- 0.7% in terms of relative error (RE). T_(max), C_(max), T_(1/2) andAUC_(0-24h), values were found to be (3.1 +- 2.7)h, (8 750+-4734) ng·mL^(-1), (5.3+-2.2) h, and(5932+-2449)ng·mL^(-1), respectively, after a single oral dose of 250 mg clarithromycin tablet to18 volunteers. Conclusion This validated method was successful in the evaluation of phaimacokineticprofiles of clarithromycin tablets administered to 18 healthy male volunteers. 展开更多
关键词 CLARITHROMYCIN LC-MS-MS pharmaookmeties
下载PDF
Determination of interference fit value on entire roller embedded shapemeter roll 被引量:5
11
作者 吴海淼 刘宏民 +1 位作者 于丙强 杨利坡 《Journal of Central South University》 SCIE EI CAS 2014年第12期4503-4508,共6页
For entire roller embedded shapemeter roll, the relationship between the value of interference fit and the sensor pre-pressure, and the pressure transfer performance of shapemeter roll were analyzed by elasticity theo... For entire roller embedded shapemeter roll, the relationship between the value of interference fit and the sensor pre-pressure, and the pressure transfer performance of shapemeter roll were analyzed by elasticity theory during the cold reversible rolling process. Considering the influence of strip temperature on the interference fit, the distributions of contact pressure of the framework's top surface and the sensor pre-pressure on different values of interference fit were analyzed by the finite element technology. The results show that the contact pressure of the framework's top surface and the sensor pre-pressure increase with the increase of the value of interference fit. When the value of interference fit is between 0.05 mm and 0.09 mm, roll body's inner hole surface, the framework and pressure magnetic sensitive component don't separate from each other, and the sensor works in the linear segment of characteristic curve, so the normal operation of shapemeter roll is guaranteed. 展开更多
关键词 reversible rolling shapemeter roll value of interference fit contact pressure finite element
下载PDF
Increase in Probability of the Correct Forecast of Tsunami Formation
12
作者 V.I. Korochentsev E.V. Lisunov P.P. Sherbakov 《Journal of Environmental Science and Engineering》 2011年第6期716-719,共4页
The presented paper exhibits theory of the "gravitational" waves propagation near the Earth surface and in the ocean. There was determined an expression "gravitational" wave which was registered by the gravimeters... The presented paper exhibits theory of the "gravitational" waves propagation near the Earth surface and in the ocean. There was determined an expression "gravitational" wave which was registered by the gravimeters being placed in several points of the Earth globe. Alteration of gravitational field was accompanied by alteration of the "gravitational" wave which has the velocity differing from the velocity of seismic waves. The theoretical model was proved by many experiments realized under registration of the underwater earthquake core by tens of gravimeters being placed in the Earth globe different points. The "gravitational" waves assist to increase the right forecast probability of the beginning tsunami to 50%. 展开更多
关键词 TSUNAMI EARTHQUAKE gravitational waves tsunami forecast.
下载PDF
STUDY OF A COMPREHENSIVE MONITORING INDEX FOR TWO TYPES OF ENSO EVENTS 被引量:1
13
作者 曹璐 孙丞虎 +2 位作者 任福民 袁媛 江静 《Journal of Tropical Meteorology》 SCIE 2015年第2期153-160,共8页
Some recent studies presented two existing types of ENSO events, one is the Eastern-Pacific(EP) type and the other the Central-Pacific(CP) type. This study examined the monitoring ability of several current operationa... Some recent studies presented two existing types of ENSO events, one is the Eastern-Pacific(EP) type and the other the Central-Pacific(CP) type. This study examined the monitoring ability of several current operational ENSO indices. The results indicated that a single index could not distinguish the EP and CP in the historical ENSO events during 1950-2009. The Nio 3 index may only be suitable for monitoring the EP-type ENSO, while the Nio 4 index works only for the CP-type ENSO. In order to capture the occurrence of ENSO events and distinguish the type, we considered a new monitoring index group using Nio 3 and Nio 4 indices. Further analysis confirmed that this index group can monitor different types of historical ENSO events with different spatial distribution of sea surface temperature. It has a good performance in determining the characteristics of the ENSO events, including peak intensity, onset,decay, and mature phase. 展开更多
关键词 ENSO events Eastern-Pacific (EP) type Central-Pacific (CP) type ENSO index index group
下载PDF
Experimental study on the variation law of coal temperature during excavation in coal mines
14
作者 Yi-Shan PAN Lian-Man XU Zhong-Hua LI Guo-Zhen LI 《Journal of Coal Science & Engineering(China)》 2013年第2期133-135,共3页
By testing the temperature of the coal and the stress of the working surface, we got the variation law of coal temperature and coal stress during the excavation. The result shows that the activities of mining affect t... By testing the temperature of the coal and the stress of the working surface, we got the variation law of coal temperature and coal stress during the excavation. The result shows that the activities of mining affect the coal temperature, the fluctuation of coal temperature and the coal stress is synchronous. During the smooth change of crustal stress, the coal temperature basically keeps unchanged, when the dynamic phenomenon appears, the coal temperature changes, as well the coal stress. Therefore, we can use the online coal temperature monitoring system to test the coal temperature of the working surface continuously, and it can provide basic information for forecasting coal mine power disaster before it happens. 展开更多
关键词 coal temperature coal stress coal fracturing gas desorption
下载PDF
Refueling Test System Completed In-orbit Verification
15
作者 YAO Tianyu 《Aerospace China》 2016年第3期62-62,共1页
The in-orbit verification of a refueling test system has been completed successfully.The test system based on a surface tension tank was developed by the Beijing Institute of Control Engineering(BICE),CAST and launc... The in-orbit verification of a refueling test system has been completed successfully.The test system based on a surface tension tank was developed by the Beijing Institute of Control Engineering(BICE),CAST and launched into spacewith the Tianyuan 1 satellite aboard a LM-7 carrier rocket on June 25.The lifetime of any spacecraft is constrained by fuel it carried. 展开更多
关键词 orbit spacecraft completed verification safely lifetime effec rocket constrained CAST
下载PDF
Windtunnel studies of surface shear stress vector distribution measurement using shear sensitive liquid crystal coatings 被引量:2
16
作者 ZHAO JiSong SCHOLZ Peter GU LiangXian 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第10期2730-2734,共5页
Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface she... Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface shear stress measurement technique de-termined by Reda et al. to wind tunnel studies. All the facilities employed in the technique are very common and simple. The measurement technique is applied to surface flow beneath a tangential jet and surface flow in a turbulence wedge generated by a small cylinder in windtunnel flow. Spatially resolved shear stresses over planar surface are obtained, although the magnitude is not fully calibrated. 展开更多
关键词 shear sensitive liquid crystal surface shear stress measurement tangential jet flow turbulence wedge
原文传递
Damage detection of long-span bridges using stress influence lines incorporated control charts 被引量:9
17
作者 CHEN ZhiWei CAI QinLin +1 位作者 LEI Ying ZHU SongYe 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第9期1689-1697,共9页
Numerous long-span bridges have been built throughout the world in recent years.These bridges are progressively damaged by continuous usage throughout their long service life.The failure of local structural components... Numerous long-span bridges have been built throughout the world in recent years.These bridges are progressively damaged by continuous usage throughout their long service life.The failure of local structural components is detrimental to the performance of the entire bridge,furthermore,detecting the local abnormality at an early stage is difficult.This paper explores a novel damage detection method for long-span bridges by incorporating stress influence lines(SILs)in control charts,and validates the efficacy of the method through a case study of the Tsing Ma Suspension Bridge.Damage indices based on SILs are subsequently proposed and applied to hypothetical damage scenarios in which one or two critical bridge components are subjected to severe damage.The comparison study suggests that the first-order difference of SIL change is an accurate indicator for location of the damage.To some extent,different levels of damage can be quantified by using SILs incorporating with X-bar control chart.Results of this study indicate that the proposed SIL-based method offers a promising technique for damage detection in long-span bridges. 展开更多
关键词 damage detection long-span bridges stress influence line control chart structural health monitoring
原文传递
Trajectory design for the Moon departure libration point mission in full ephemeris model 被引量:3
18
作者 CHEN Yang BAOYIN +1 位作者 HeXi LI JunFeng 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第11期2924-2934,共11页
The lunar probe may still have some remaining fuel after completing its predefined Moon exploration mission and is able to carry out some additional scientific or technological tasks after escaping from the Moon orbit... The lunar probe may still have some remaining fuel after completing its predefined Moon exploration mission and is able to carry out some additional scientific or technological tasks after escaping from the Moon orbit.The Moon departure mission for the lunar probe is the focus of this paper.The possibility of the spacecraft orbiting the Moon to escape the Moon's gravitational pull is analyzed.The trajectory design for the Earth-Moon system libration point mission is studied in a full ephemeris dynamical model,which considers the non-uniform motion of the Moon around the Earth,the gravity of the Sun and planets and the finite thrust of the onboard engine.By applying the Particle Swarm Optimization algorithm,the trajectory design for the transfer from the Moon-centered orbit to the L1 halo orbit,the station-keeping strategies for the Earth-Moon halo orbit and the construction of homoclinic and heteroclinic orbits are investigated.Taking the tracking conditions and engineering constraints into account,two feasible schemes for the Moon departure libration point mission for the lunar probe are presented. 展开更多
关键词 Moon exploration trajectory design full ephemeris model libration point halo orbit
原文传递
RNA-seq reveals the critical role of Csp A in regulating Brucella melitensis metabolism and virulence 被引量:5
19
作者 Zhen Wang Wenxiao Liu +2 位作者 Tonglei Wu Pengfei Bie Qingmin Wu 《Science China(Life Sciences)》 SCIE CAS CSCD 2016年第4期417-424,共8页
Brucella melitensis is a facultative intracellular bacterium that replicates within macrophages. The ability of Brucella to survive and multiply in the hostile environment of host macrophages is essential for its viru... Brucella melitensis is a facultative intracellular bacterium that replicates within macrophages. The ability of Brucella to survive and multiply in the hostile environment of host macrophages is essential for its virulence. The cold shock protein Csp A plays an important role in the virulence of B. melitensis. To analyze the genes regulated by Csp A, the whole transcriptomes of B. melitensis NI?csp A and its parental wild-type strain, B. melitensis NI, were sequenced and analyzed using the Solexa/Illumina sequencing platform. A total of 446 differentially expressed genes were identified, including 324 up-regulated and 122 down-regulated genes. Numerous genes identified are involved in amino acid, fatty acid, nitrogen, and energy metabolism. Interestingly, all genes involved in the type IV secretion system and Lux R-type regulatory protein Vjb R were significantly down-regulated in NI?csp A. In addition, an effector translocation assay confirmed that the function of T4 SS in NI?csp A is influenced by deletion of the csp A gene. These results revealed the differential phenomena associated with virulence and metabolism in NI?csp A and NI, providing important information for understanding detailed Csp A-regulated interaction networks and Brucella pathogenesis. 展开更多
关键词 Brucella melitensis cold shock protein transcriptome virulence
原文传递
Effects of a Kind of Surface Groove on Flow Loss in Both Rectangular and Circular Ducts at Different Reynolds Numbers 被引量:3
20
作者 MA Rong MA Hongwei +1 位作者 ZHANG Zhenyang ZHANG Jinghui 《Journal of Thermal Science》 SCIE EI CAS CSCD 2016年第5期389-393,共5页
Pipes are widely used to transport gas,oil and water in industries.Drag reduction in pipes is an increasingly concerned problem to save energy.Some researches have indicated that the non-smooth surface with special st... Pipes are widely used to transport gas,oil and water in industries.Drag reduction in pipes is an increasingly concerned problem to save energy.Some researches have indicated that the non-smooth surface with special structures can reduce flow loss.In this paper,an experimental investigation has been performed on the effects of a kind of surface groove on the drag in both rectangular and circular duct at different Reynolds numbers.In the experiment of the rectangular duct,total pressure at both inlet and outlet were measured.Static pressure on the wall was measured on the surface with smooth and grooved film respectively.In the circular duct,a boundary layer pressure probe was used to measure the total pressure distribution at both inlet and outlet.Four taps at inlet and outlet were used to measure static pressure.The loss coefficient is used to evaluate the effects of the surface groove on drag reduction.The experiment was conducted with the Reynolds number range from 1.28×10~4 to 2.57×10~4.The result shows a maximum drag loss reduction of approximately 2.4% in rectangular duct at Reynolds number of 2.4×10~4.A 10%reduction of pipe pressure loss by grooved surface is measured in circular duct at a Reynolds number of 3.0×10~5. 展开更多
关键词 drag reduction surface groove rectangular duct circular duct
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部