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Study on the Improvement in the One Dimensional Mathematical Model of the Air Drag in Melt Blowing Process
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作者 陈廷 黄秀宝 《Journal of China Textile University(English Edition)》 EI CAS 2000年第4期1-4,共4页
The one dimensional mathematical model of the air drag in melt blowing process, which had been put forward by Uyttendaele and Shambaugh is improved. The influence of the density and the specific heat capacity of polym... The one dimensional mathematical model of the air drag in melt blowing process, which had been put forward by Uyttendaele and Shambaugh is improved. The influence of the density and the specific heat capacity of polymer melt at constant pressure changing with polymer temperature on fiber diameter are studied. The power - law model is introduced as the constitutive equation. The influences of polymer volume flow rate, initial polymer temperature, initial air velocity and initial air temperature on fiber diameter are discussed. 展开更多
关键词 MELT BLOWING air drag MICROFIBER nonwaven FABRIC
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Comparison of Microbubble and Air Layer Injection with Porous Media for Drag Reduction on a Self-propelled Barge Ship Model 被引量:3
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作者 Yanuar Kurniawan T.Waskito +2 位作者 Sigit Y.Pratama Bagus D.Candra Bilmantasya A.Rahmat 《Journal of Marine Science and Application》 CSCD 2018年第2期165-172,共8页
Ship resistance issues are related to fuel economy,speed,and cost efficiency.Air lubrication is a promising technique for lowering hull frictional resistance as it is supposed to modify the energy in the turbulent bou... Ship resistance issues are related to fuel economy,speed,and cost efficiency.Air lubrication is a promising technique for lowering hull frictional resistance as it is supposed to modify the energy in the turbulent boundary layer and thereby reduce hull friction.In this paper,the objective is to identify the optimum type of air lubrication using microbubble drag reduction(MBDR)and air layer drag reduction(ALDR)techniques to reduce the resistance of a 56-m Indonesian self-propelled barge(SPB).A model with the following dimensions was constructed:length L=2000 mm,breadth B=521.60 mm,and draft T=52.50 mm.The ship model was towed using standard towing tank experimental parameters.The speed was varied over the Froude number range 0.11–0.31.The air layer flow rate was varied at 80,85,and 90 standard liters per minute(SLPM)and the microbubble injection coefficient over the range 0.20–0.60.The results show that the ship model using the air layer had the highest drag reduction up to a maximum of 90%.Based on the characteristics of the SPB,which operates at low speed,the optimum air lubrication type to reduce resistance in this instance is ALDR. 展开更多
关键词 SELF-PROPELLED BARGE Ship resistance air lubrication MICROBUBBLE drag REDUCTION air layer drag REDUCTION
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Experimental Study of Air Layer Drag Reduction with Bottom Cavity for A Bulk Carrier Ship Model 被引量:3
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作者 WU Hao OU Yong-peng 《China Ocean Engineering》 SCIE EI CSCD 2019年第5期554-562,共9页
Air lubrication by means of a bottom cavity is a promising method for ship drag reduction. The characteristics of the bottom cavity are sensitive to the flow field around the ship hull and the effect of drag reduction... Air lubrication by means of a bottom cavity is a promising method for ship drag reduction. The characteristics of the bottom cavity are sensitive to the flow field around the ship hull and the effect of drag reduction, especially the depth of the bottom cavity. In this study, a ship model experiment of a bulk carrier is conducted in a towing tank using the method of air layer drag reduction (ALDR) with different bottom cavity depths. The shape of the air layer is observed, and the changes in resistance are measured. The model experiments produce results of approximately 20% for the total drag reduction at the ship design speed for a 25-mm cavity continuously supplied with air at Cq = 0.224 in calm water, and the air layer covers the whole cavity when the air flow rate is suitable. In a regular head wave, the air layer is easily broken and reduces the drag reduction rate in short waves, particularly when λ/Lw1 is close to one;however, it still has a good drag reduction effect in the long waves. 展开更多
关键词 air LAYER drag reduction BULK CARRIER model test DEPTH of CAVITY air LAYER shape
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Computational Solution to the Problems of Projectile Motion under Significant Linear Drag Effect
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作者 Annasi Ayubu Said Msafiri Mmasa Mshewa +2 位作者 Grant Charles Mwakipunda Mbega Ramadhani Ngata Elfakiri Ali Mohamed 《Open Journal of Applied Sciences》 CAS 2023年第4期508-528,共21页
This paper investigates the computational solution to the problem of projectile motion under a significant linear drag effect. The drag force acting on the particle within the medium of propagation is proportional to ... This paper investigates the computational solution to the problem of projectile motion under a significant linear drag effect. The drag force acting on the particle within the medium of propagation is proportional to the cross-section area of the projectile, the velocity of the particle, and the medium’s density. From zero air resistance force (vacuum) the problems are well known with solutions, but with air resistance (drag force) the problems have no exact analytical solutions which lead to most of the significant scientific research works using numerical methods. Therefore, this study aims to present the analysis of the computational modelling of drag force exerted by the surrounding medium on the linear motion. However, the horizontal and vertical components of differential equations of motion were derived and characterized from the solutions governed by Newton’s 2<sup>nd</sup> law of motion. The baseball features were presented as the projectile (object) in this work. In addition, the numerical computational results were received from FreeMat. The results were discussed and compared with those from the vacuum. Moreover, the displacements, velocities, range, and trajectories of the projectile were all discussed and a conclusion was made. 展开更多
关键词 drag Force air Resistance PROJECTILE Newton’s Law
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气体润滑减阻研究综述
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作者 秦世杰 季盛 +1 位作者 伍锐 吴大转 《船舶力学》 EI CSCD 北大核心 2024年第6期951-966,共16页
在我国“碳达峰、碳中和”战略背景下,气体润滑减阻作为一种流动控制节能与降碳方法,可有效降低船舶航行阻力,对我国船舶及航运业的低碳发展意义重大。本文介绍了气体润滑减阻研究的国内外背景及意义,阐述了气体润滑减阻的定义及分类方... 在我国“碳达峰、碳中和”战略背景下,气体润滑减阻作为一种流动控制节能与降碳方法,可有效降低船舶航行阻力,对我国船舶及航运业的低碳发展意义重大。本文介绍了气体润滑减阻研究的国内外背景及意义,阐述了气体润滑减阻的定义及分类方式,特别是提出了基于气液两相界面形态与减阻机理的离散气泡减阻和连续气层减阻分类方式,并在此基础上分别梳理了离散气泡减阻和连续气层减阻在减阻特性、减阻机理、两相流态及其影响因素等方面的进展情况,总结并展望了气体润滑减阻的研究现状和该领域的未来发展趋势。 展开更多
关键词 气体润滑 离散气泡 连续气层 减阻 节能 降碳 船舶
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大尺度自航模气层减阻试验研究
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作者 吴浩 杨子烨 +1 位作者 曹建鑫 欧勇鹏 《中国舰船研究》 CSCD 北大核心 2024年第5期43-48,共6页
[目的]旨在研究气流量、航行倾角对船底凹槽内气层保持和节能效果的影响。[方法]以一艘肥大型散货船的较大尺度缩比模型为研究对象,通过设计气层减阻自航模系统和船底凹槽方案,开展开阔水域条件下自航模气层减阻试验,研究模型正浮状态... [目的]旨在研究气流量、航行倾角对船底凹槽内气层保持和节能效果的影响。[方法]以一艘肥大型散货船的较大尺度缩比模型为研究对象,通过设计气层减阻自航模系统和船底凹槽方案,开展开阔水域条件下自航模气层减阻试验,研究模型正浮状态下喷气减阻效果,以及模型一定纵倾角状态下对航速和轴功率的影响。[结果]结果表明:在主机转速一定时,喷气可以明显提高自航模的航速,停止喷气后,船底凹槽内的气体仍能维持较长时间;船体艉倾角为0°~0.25°时的气层减阻效果较好,较大艉倾角时气体从自航模艏部两侧溢出,气层无法对船底实现有效覆盖,减阻效果不佳。[结论]研究结果可对气层减阻技术在肥大型船舶上的工程应用提供一定参考。 展开更多
关键词 自航模型 喷气装置 气层保持性 减阻 节能
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船舶气层减阻技术研究综述
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作者 赵大刚 高适 +1 位作者 张顺 钟祥海 《船舶工程》 CSCD 北大核心 2024年第4期18-28,共11页
随着全球生态环境变化的要求以及我国“碳达峰、碳中和”目标的提出,船舶气层减阻技术作为船舶运输手段中一种有效的节能、降碳手段,近年来备受关注。文章阐述了气层减阻技术中气层的形成过程以及工作原理;从模型试验以及理论与数值计... 随着全球生态环境变化的要求以及我国“碳达峰、碳中和”目标的提出,船舶气层减阻技术作为船舶运输手段中一种有效的节能、降碳手段,近年来备受关注。文章阐述了气层减阻技术中气层的形成过程以及工作原理;从模型试验以及理论与数值计算方面分析了船舶气层减阻技术的发展和研究现状;列举分析了国内外部分研究单位的应用实例和实际效果;针对研究和应用现状,对船舶气层减阻技术面对的问题和未来发展方向进行了展望。 展开更多
关键词 气层减阻 气泡减阻 实船应用 降碳
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PSA装置C201-3一级右列做功差原因分析及处理措施
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作者 白易昌 韩颖 +1 位作者 吕怀生 左小虎 《聚酯工业》 CAS 2024年第5期35-38,共4页
PSA装置解析气压缩机因发现振动大和异常声音而停机,检修完毕后出现一级右列做功差的现象,结合两次试机过程,并逐项排查各影响因素后,判断为气阀本身密封面失效导致吸入性能变差。结合本次检修的拆解情况,从工艺流程和气阀改型两方面提... PSA装置解析气压缩机因发现振动大和异常声音而停机,检修完毕后出现一级右列做功差的现象,结合两次试机过程,并逐项排查各影响因素后,判断为气阀本身密封面失效导致吸入性能变差。结合本次检修的拆解情况,从工艺流程和气阀改型两方面提出应对措施,以期为相关研究提供参考。 展开更多
关键词 气阀 负荷调节器 黏滞力
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基于大气阻力实时辨识的Drag-free卫星最优控制研究 被引量:1
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作者 党朝辉 项军华 曾国强 《上海航天》 2010年第6期6-10,60,共6页
研究了基于大气阻力实时辨识的Drag-free卫星最优控制。将Drag-free卫星和其内部的验证质量等效为两颗内、外编队卫星并建立动力学方程,推导了基于卫星和验证质量的相对运动状态观测值反演大气阻力的算法。建立了状态最优调节器模型,采... 研究了基于大气阻力实时辨识的Drag-free卫星最优控制。将Drag-free卫星和其内部的验证质量等效为两颗内、外编队卫星并建立动力学方程,推导了基于卫星和验证质量的相对运动状态观测值反演大气阻力的算法。建立了状态最优调节器模型,采用动态规划求解经典的二次型最优控制。对低轨圆轨道Drag-free卫星的仿真计算结果表明方法的求解精度较高,计算消耗较小。 展开更多
关键词 drag-free卫星 跟踪保持 最优控制 大气阻力 实时辨识
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水下高压抗润湿V型槽分级铜纳米线簇超疏水表面的减阻研究
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作者 张祺瑞 李启迅 +2 位作者 阮达 刘渊博 马学虎 《高校化学工程学报》 EI CAS CSCD 北大核心 2024年第4期558-565,共8页
针对水下减阻超疏水表面气层稳定性差的问题,提出了在金属铜基底上使用两步电化学沉积法,制备了一种具有V型槽结构、区室化簇状结构和微纳分级结构的铜纳米线超疏水表面,进行了水下高压气层稳定性测试和减阻测试。结果表明,该表面最高可... 针对水下减阻超疏水表面气层稳定性差的问题,提出了在金属铜基底上使用两步电化学沉积法,制备了一种具有V型槽结构、区室化簇状结构和微纳分级结构的铜纳米线超疏水表面,进行了水下高压气层稳定性测试和减阻测试。结果表明,该表面最高可在0.45 MPa水压下维持76%的未润湿区域。同时,该表面在平板流变仪层流减阻测试中可取得高达56%的减阻率,具有优异的减阻性能。V型槽分级铜纳米线簇超疏水表面兼具水下高压气层稳定性和减阻效果,可应用到实际船舶航行领域,为解决超疏水表面减阻应用的瓶颈问题提供方案。 展开更多
关键词 超疏水表面减阻 分级结构 气层稳定性 铜纳米线
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单叶风阀调节性能试验研究
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作者 郭绍华 魏兵 《阀门》 2024年第4期418-423,共6页
文章主要研究了不同规格的单叶风阀在不同开度或风量下的调节性能。本文在保持风量不变的情况下,通过改变风阀的开度,测试了风管内部压力、风速、阻力等参数,以及在开度不变的情况下改变风量,测试了不同开度下风管内部压力、风速、阻力... 文章主要研究了不同规格的单叶风阀在不同开度或风量下的调节性能。本文在保持风量不变的情况下,通过改变风阀的开度,测试了风管内部压力、风速、阻力等参数,以及在开度不变的情况下改变风量,测试了不同开度下风管内部压力、风速、阻力等参数。找到了不同工况下,风管内部气流从距离阀门6倍管径处开始稳定,以及风阀阻力、风速随风阀开度变化的规律基本呈“指数型”,风阀阻力随风量变化的规律基本呈“线性”,风阀调节对管路影响的不敏感区处于0°~45°,敏感区域处于45°~80°。以上结论在200×200 mm与300×300 mm规格的方形风管与阀门中均成立。 展开更多
关键词 电动调节阀 风阀动态性能测试 风速 压力 阻力系数
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超低轨吸气式电推进飞行器维轨关键问题探讨与展望
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作者 江一鹏 崔玉福 贾晓冬 《先进小卫星技术(中英文)》 2024年第4期31-40,共10页
气动阻力过大导致的轨道快速衰减问题是超低轨飞行器面临的主要挑战,需采用发动机推力进行阻力补偿,而能否产生充足的净推力是超低轨飞行器任务成败的关键.介绍了吸气式电推进飞行器的阻力情况和混合工质离子发动机的推力情况及主要影... 气动阻力过大导致的轨道快速衰减问题是超低轨飞行器面临的主要挑战,需采用发动机推力进行阻力补偿,而能否产生充足的净推力是超低轨飞行器任务成败的关键.介绍了吸气式电推进飞行器的阻力情况和混合工质离子发动机的推力情况及主要影响要素,提出了有关减少阻力及增加推力的几点建议.基于吸气式电推进飞行器长期维轨及可能的轨道调整需求,建议采取最大净推力及最大推阻比两种构型设计方案.针对空间环境变化带来推力器性能不足的问题,分析了基于蓄电池调节和储气调节这两种方式的优缺点及各自适用范围.就吸气式电推进长期维轨需要的关键技术及涉及的科学问题进行了讨论,并给出了未来研究方向以供参考. 展开更多
关键词 超低轨道 吸气式电推进 稀薄气体 净推力 推阻比
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Damping of a Simple Pendulum Due to Drag on Its String 被引量:1
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作者 Pirooz Mohazzabi Siva P. Shankar 《Journal of Applied Mathematics and Physics》 2017年第1期122-130,共9页
A basic classical example of simple harmonic motion is the simple pendulum, consisting of a small bob and a massless string. In a vacuum with zero air resistance, such a pendulum will continue to oscillate indefinitel... A basic classical example of simple harmonic motion is the simple pendulum, consisting of a small bob and a massless string. In a vacuum with zero air resistance, such a pendulum will continue to oscillate indefinitely with a constant amplitude. However, the amplitude of a simple pendulum oscillating in air continuously decreases as its mechanical energy is gradually lost due to air resistance. To this end, it is generally perceived that the main role in the dissipation of mechanical energy is played by the bob of the pendulum, and that the string’s contribution is negligible. The purpose of this research is to experimentally investigate the merit of this assumption. Thus, we experimentally investigate the damping of a simple pendulum as a function of its string diameter and compare that to the contribution from its bob. We find out that although in some cases the effect of the string might be small or even negligible, in general the string can play a significant role, and in some cases even a greater role on the damping of the pendulum than its bob. 展开更多
关键词 SIMPLE PENDULUM STRING DAMPING air RESISTANCE drag
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船舶气体润滑减阻应用现状及展望 被引量:1
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作者 秦世杰 季盛 +2 位作者 孙帅 伍锐 吴大转 《中国舰船研究》 CSCD 北大核心 2023年第6期1-10,共10页
随着国际航运减排新规和国内“双碳”战略的实施,船舶气体润滑减阻作为一种新型船舶节能降碳技术,备受航运与船舶工业关注。目前,根据气体润滑的减阻机理及其两相界面形态,主要可将其分为连续气层减阻与离散气泡减阻。文中分别介绍连续... 随着国际航运减排新规和国内“双碳”战略的实施,船舶气体润滑减阻作为一种新型船舶节能降碳技术,备受航运与船舶工业关注。目前,根据气体润滑的减阻机理及其两相界面形态,主要可将其分为连续气层减阻与离散气泡减阻。文中分别介绍连续气层减阻与离散气泡减阻的国内外实船应用现状,重点对气体润滑的实船布置、形式、减阻和节能效果等进行综述,并根据已有实船应用中报道的净节能情况,对气体润滑减阻船舶的节能与降碳效果进行分析。最后,对气体润滑减阻在实船应用中面临的技术挑战及值得深入研究的方向进行简要展望。 展开更多
关键词 船舶减阻 气体润滑减阻 节能 降碳 航运
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Sensitivity Analysis of Air Gap Motion with Respect to Wind Load and Mooring System for Semi-Submersible Platform Design 被引量:5
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作者 霍发力 聂焱 +2 位作者 杨德庆 董刚 崔锦 《China Ocean Engineering》 SCIE EI CSCD 2016年第4期535-548,共14页
A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and po... A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and potential deck impact to the semi-submersible platform. It is important to predict air gap response of platforms accurately in order to check the strength of local structures which withstand the wave slamming due to negative air gap. The wind load cannot be simulated easily by model test in towing tank whereas it can be simulated accurately in wind tunnel test. Furthermore, full scale simulation of the mooring system in model test is still a tuffwork especially the stiffness of the mooring system. Owing to the above mentioned problem, the model test results are not accurate enough for air gap evaluation. The aim of this paper is to present sensitivity analysis results of air gap motion with respect to the mooring system and wind load for the design of semi-submersible platform. Though the model test results are not suitable for the direct evaluation of air gap, they can be used as a good basis for tuning the radiation damping and viscous drag in numerical simulation. In the presented design example, a numerical model is tuned and validated by ANSYS AQWA based on the model test results with a simple 4 line symmetrical horizontal soft mooring system. According to the tuned numerical model, sensitivity analysis studies of air gap motion with respect to the mooring system and wind load are performed in time domain. Three mooring systems and five simulation cases about the presented platform are simulated based on the results of wind tunnel tests and sea-keeping tests. The sensitivity analysis results are valuable for the floating platform design. 展开更多
关键词 mooring system air gap semi-submersible platform radiation damping viscous drag
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高速列车车身喷射氦气气动减阻研究 被引量:3
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作者 熊小慧 谢鹏辉 +3 位作者 梁习锋 张昕 杨波 胡天恩 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2023年第2期432-440,共9页
传统的列车头尾外形优化及车体平顺化气动减阻方式已趋于减阻极限,应用流动控制技术来降低列车表面摩擦阻力成为实现列车气动减阻的重要途径之一。采用改进的延迟分离涡模拟方法(IDDES)对高速列车头车车身向外喷射氦气的主动控制减阻技... 传统的列车头尾外形优化及车体平顺化气动减阻方式已趋于减阻极限,应用流动控制技术来降低列车表面摩擦阻力成为实现列车气动减阻的重要途径之一。采用改进的延迟分离涡模拟方法(IDDES)对高速列车头车车身向外喷射氦气的主动控制减阻技术进行研究,分析喷气速度、喷气部位以及喷气方式对列车气动阻力及周围流场结构的影响。研究结果表明:等截面车身顶面喷气时,随着喷气速度提高,减阻效果减弱,当以0.1U(U为来流速度)喷气时,具有最佳气动减阻效果,整车气动减阻率为3.68%,对比各节车在不同喷气速度下摩擦阻力变化,当喷气速度较低时对各节车均有减阻效果,而喷气速度越高,对中间车和尾车的减阻效果越差,甚至产生增阻效果。头车流线型与等截面车身过渡位置和等截面车身顶面分别以0.1U喷气时均降低了列车整车阻力,流线型头部过渡位置顶面喷气时整车减阻2.22%,减阻率小于等截面车身顶面喷气。当喷气速度为0.1U时,相较于等截面车身顶面或侧面单独喷气,顶面和侧面同时喷气减阻效果最佳,整车气动减阻率达到10.93%,喷射出的氦气在列车表面附着情况比顶面或侧面单独喷气时的效果更好,列车顶面到侧面过渡区域的壁面剪切应力有效降低。研究结果为高速列车气动减阻提供新思路,对克服由于空气动力效应带来的提速瓶颈具有重要意义。 展开更多
关键词 高速列车 气动减阻 表面吹气 数值模拟
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Air Plasma Mitigation of Shock Wave 被引量:2
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作者 Spencer P. Kuo 《Advances in Aerospace Science and Technology》 2016年第2期59-69,共11页
Shock wave is a detriment in the development of supersonic aircrafts;it increases flow drag as well as surface heating from additional friction;it also initiates sonic boom on the ground which precludes supersonic jet... Shock wave is a detriment in the development of supersonic aircrafts;it increases flow drag as well as surface heating from additional friction;it also initiates sonic boom on the ground which precludes supersonic jetliner to fly overland. A shock wave mitigation technique is demonstrated by experiments conducted in a Mach 2.5 wind tunnel. Non-thermal air plasma generated symmetrically in front of a wind tunnel model and upstream of the shock, by on-board 60 Hz periodic electric arc discharge, works as a plasma deflector, it deflects incoming flow to transform the shock from a well-defined attached shock into a highly curved shock structure. In a sequence with increasing discharge intensity, the transformed curve shock increases shock angle and moves upstream to become detached with increasing standoff distance from the model. It becomes diffusive and disappears near the peak of the discharge. The flow deflection increases the equivalent cone angle of the model, which in essence, reduces the equivalent Mach number of the incoming flow, manifesting the reduction of the shock wave drag on the cone. When this equivalent cone angle exceeds a critical angle, the shock becomes detached and fades away. This shock wave mitigation technique helps drag reduction as well as eliminates sonic boom. 展开更多
关键词 Shock Wave Mitigation Electric Discharge air Plasma Deflector SHADOWGRAPH drag Reduction Wind Tunnel Charge Transfer
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Shock Wave Mitigation by Air Plasma Deflector
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作者 Spencer P. Kuo 《Advances in Aerospace Science and Technology》 2018年第4期71-88,共18页
When the spacecraft flies much faster than the sound speed (~1200 km/h), the airflow disturbances deflected forward from the spacecraft cannot get away from the spacecraft and form a shock wave in front of it. Shock w... When the spacecraft flies much faster than the sound speed (~1200 km/h), the airflow disturbances deflected forward from the spacecraft cannot get away from the spacecraft and form a shock wave in front of it. Shock waves have been a detriment for the development of supersonic aircrafts, which have to overcome high wave drag and surface heating from additional friction. Shock wave also produces sonic booms. The noise issue raises environmental concerns, which have precluded routine supersonic flight over land. Therefore, mitigation of shock wave is essential to advance the development of supersonic aircrafts. A plasma mitigation technique is studied. A theory is presented to show that shock wave structure can be modified via flow deflection. Symmetrical deflection evades the need of exchanging the transverse momentum between the flow and the deflector. The analysis shows that the plasma generated in front of the model can effectively deflect the incoming flow. A non-thermal air plasma, generated by on-board 60 Hz periodic electric arc discharge in front of a wind tunnel model, was applied as a plasma deflector for shock wave mitigation technique. The experiment was conducted in a Mach 2.5 wind tunnel. The results show that the air plasma was generated symmetrically in front of the wind tunnel model. With increasing discharge intensity, the plasma deflector transforms the shock from a welldefined attached shock into a highly curved shock structure with increasing standoff distance from the model;this curved shock has increased shock angle and also appears in increasingly diffused form. In the decay of the discharge intensity, the shock front is first transformed back to a well-defined curve shock, which moves downstream to become a perturbed oblique shock;the baseline shock front then reappears as the discharge is reduced to low level again. The experimental observations confirm the theory. The steady of the incoming flow during the discharge cycle is manifested by the repeat of the baseline shock front. 展开更多
关键词 Shock Wave MITIGATION Electric DISCHARGE air Plasma DEFLECTOR SHADOWGRAPH drag Reduction Wind TUNNEL Charge Transfer
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Realization of non HF air plasma cutting power source based on a complexisolated inverter
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作者 柳刚 胡绳荪 +1 位作者 范荣焕 孙栋 《China Welding》 EI CAS 1999年第2期33-37,共5页
On the basis of analyzing and testing of common inverting circuits, a new type inverter, which has a special inverting circuit called complex isolated, has been put forward. In turn, an applicable air plasma cutting ... On the basis of analyzing and testing of common inverting circuits, a new type inverter, which has a special inverting circuit called complex isolated, has been put forward. In turn, an applicable air plasma cutting machine has also been put into use. Testing results show that this kind inverter has lots of properties as high reliability, high efficiency, good EMC(electromagnetic compatibility) and easy operating. The complex isolated inverting circuit can be considered as a quite valuable reference for the research of high power welding inverter. 展开更多
关键词 complex isolated inverting circuit air plasma cutting non HF sparking inner drag output characteristics
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船舶减阻技术方法综述 被引量:2
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作者 王帅 李淑江 +1 位作者 鉴冉冉 邓芳 《船舶工程》 CSCD 北大核心 2023年第4期66-78,共13页
快速性是船舶航行的重要性能之一,新型减阻技术不断被提出推动了船舶快速性的发展。从船舶阻力原理出发,对国内外船舶减阻技术展开分析,指出当前主流研究方向为空气减阻、仿生超疏水减阻、附体减阻以及断级减阻技术;针对这4种减阻技术... 快速性是船舶航行的重要性能之一,新型减阻技术不断被提出推动了船舶快速性的发展。从船舶阻力原理出发,对国内外船舶减阻技术展开分析,指出当前主流研究方向为空气减阻、仿生超疏水减阻、附体减阻以及断级减阻技术;针对这4种减阻技术探究影响减阻效果的主要因素,总结当前减阻技术中存在的问题;并介绍船体加热-超声协同减阻和网状射流等新型减阻技术,对未来减阻技术的发展进行展望,为船舶减阻技术的进一步研究提供借鉴。 展开更多
关键词 船舶阻力 空气减阻 仿生超疏水减阻 附体减阻 断级减阻
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