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双语推荐：阻力

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山区河道水流阻力研究对于认识山区河道中水流特性、山洪行进过程以及山区河道输沙规律都具有重要的意义。本文从4个方面总结前人关于山区河道水流阻力方面的研究进展,包括:(1)泥沙阻力;(2)河道底坡与水流阻力的关系;(3)典型形体阻力;(4)阻力划分。其中泥沙阻力是肤面阻力的主要来源,这是以往研究中涉及较多的内容;河道底坡属于关注较多的形体阻力;其它形体阻力包括床面沙石突起、漂浮的树木、阶梯—深潭构造等均是山区河道所特有的,研究成果相对较少。阻力划分思想为从整体上得到具有普遍意义的阻力计算式提供了有效途径,但由于山区河道的阻力形成机制和物理来源尚未完全理清,使其应用受到一定的限制。今后还需在深入了解山区河道水流阻力机理的基础上,采用阻力划分方法对阻力系数量化做进一步的研究。
Flow resistance in mountain rivers has an important impact on flow and sediment transport,espe?cially on flash torrent propagation. Many researchers have been devoting themselves to this subject and we summarize these works about flow resistance in mountain rivers from the following four aspects:(1) grain resistance;(2) relationship between flow resistance and river-bed slop;(3) form resistance;(4) resis?tance partitioning. In which, grain resistance is dominant component of surface resistance and it was stud?ied sufficiently with abundant results. Bed slope resistance is a focus of the form resistance while other par?ticular parts of the form resistance in mountain rivers, such as resistance of boulders, floating wood and step-pool system,received much less attention. The previous researches mostly focused on part of the flow resistance causing these results lack of universality. Resistance partitioning is an effective approach to solve this problem,but the mechanism and origin of flo

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分析了气囊式正压氧气呼吸器正压弹簧产生的呼吸阻力、呼吸器管道结构产生的呼吸阻力和整机呼吸阻力的影响因素,结果表明:在排除了排气阀和自动补给阀影响后,呼吸器的呼吸阻力由弹簧力和管道结构阻力决定;呼吸器结构定型以后,呼吸流量越大,呼吸阻力越大.
This paper analyzed the breathing resistance produced by the positive-pressure spring of the airbag-type positive-pressure oxygen respirator, the breathing resistance produced by the respirator's tube structure and the influence factors of the breathing resistance of the whole respirator. The results showed that the breathing resistance of the respirator was determined by the spring force and the structural resistance of the breathing tube after the influence of the exhaust valve and automatic supply valve was excluded;and the greater the breathing flow, the larger breathing resistance after the design of the respirator's structure was finalized.

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为准确评估M船型的水动力特性,掌握该船型的阻力特性和船型特征,对该船型进行阻力模型试验研究。通过测定不同排水量、不同重心纵向位置下船模的阻力值、纵倾角及重心升沉值,研究排水量和重心纵向位置对该船型阻力性能的影响。试验结果表明：M船型具有与常规滑行艇不一样的阻力特性,该船型拥有2个高速阻力峰,当航速持续增大越过第1个高速阻力峰后,阻力值有明显的回落,当航速继续增大越过第2个高速阻力峰后,阻力值基本保持不变,且2个高速阻力峰出现的航速与排水量大小和重心纵向位置的相关性不大。
In order to estimate the hydrodynamic characters and resistance of M-form hulls accurately, this paper gives an experimental study based on a M-form model. The influence of displacement and longi-tudinal center of the gravity on resistance is studied, based on different measuring resistance, trim angles, heave motions. The test results indicate that the M-form hull, unlike general planing crafts, has a particular resistance character of two resistance hump. When the sailing speed rises and exceeds the first hump, the resistance declines quite dramatically. When the sailing speed continues to rise and exceeds the second hump, the resistance maintains the same value. Besides, the sailing speed at the two resistance hump is un-related with the displacement and longitudinal center of gravity.

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本文主要对刑罚的阻力作简要分析，首先指出阻力的力量来源，分析了刑罚阻力设计的标准，并指出刑罚阻力的应用和因阻力设计不当造成的后果。最后指出刑罚只能阻止犯罪，并不能从根本上消灭犯罪。
This paper briefly analysis the main resistance on the penalty, first pointed out that the resistance of the power source, analyzed the penalty resistance design standards, and points out that the application of the resistance and resistance of the consequences due to improper design. Finally pointed out that the penalty can prevent crime, but can not fundamentally eliminate crime.

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主要从坡面流流态对坡面流阻力的影响、坡面流阻力与雷诺数的关系、降雨对坡面流阻力的影响、坡面流阻力公式4个方面对前人关于坡面流阻力的研究成果进行了总结。结果表明：坡面流流态的不确定性导致了坡面流阻力变化更为复杂；坡面流阻力与雷诺数之间并无良好单一的相关关系；降雨对坡面流阻力有很大的影响作用但具体影响机理并未有明确的结论；坡面流阻力公式表征仍用明渠水流概念及表达方式，并且3个阻力系数n、f、C哪个更适合表征坡面流阻力尚无统一的结论。进而对目前存在的问题进行了分析，对今后的发展进行了展望，认为需在研究方法和实验设备及量测技术方面有所突破，才可以更好的对坡面流阻力进行全面系统的研究。
The predecessors''research results about the overland flow resistance are summarized from the fol-lowing four aspects that the influence of overland flow resistance on slope surface flow pattern, the relation-ship between overland flow resistance and Reynolds number, the influence of rainfall on slope surface flow resistance, and overland flow resistance formula characterization.The result indicated that the uncertainty of slope surface flow pattern led to the more complicated change of overland flow resistance;there is no single good correlation between the overland flow resistance and Reynolds number;rainfall has a great influence on slope surface flow resistance but the specific influence mechanism is not clear;open channel flow concept and expression are still used in characterization of overland flow resistance formula, and there is no unified conclusion that which is more suitable for characterization of overland flow resistance of three resistance co-efficients n、f、C

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为准确评估三体槽道滑行艇的水动力性能，研究该船型的阻力特性和船型特征，对该船型进行了阻力模型试验研究。在不同排水量和重心纵向位置处进行多次拖曳阻力试验，监测其阻力值、重心升沉和纵倾角，研究了重心位置和排水量对该船型阻力性能的影响。试验结果表明：该三体槽道滑行艇有较高的承载能力且具备独特的阻力特性，当航速持续增大越过高速阻力峰时，由于气动力与水动力综合作用船体被抬升，吃水减小导致阻力值发生明显回落，且阻力峰出现的航速与重心纵向位置和排水量大小均相关。
In order to estimate the hydrodynamic characters and resistance performance of the channel type planing trimaran accurately, this paper presents a resistance experimental study based on a planing trimaran ship model. A series of towing resistance model tests were conducted to analyze the resistance, trim angles and heave motions with different displacements and gravity center positions. The influence of gravity center position and displacement on re?sistance performance of the ship model was studied. The findings indicate that the channel type planing trimaran has large displacement and unique resistance characters. When sailing speed is increasingly rising and exceeds the high?speed resistance peak, the combined effects of aerodynamic and hydrodynamic uplift the hull, obviously causing the draft of the ship to decrease and the resistance to decline rapidly. The sailing speed of the high?speed resistance peak occurring is related to both the displacements and longitudinal gravity cente

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广州地铁5号线地铁车辆为直线电机驱动车辆,为确定其运行阻力特性,在业主线路上进行增购列车运行阻力试验,推算出直线电机驱动地铁车辆的单位运行基本阻力公式,并与传统的旋转电机驱动地铁车辆的单位运行基本阻力进行比对,结果表明前者具有更好的运行阻力特性,在较高速度运行时具有更小的单位运行基本阻力.
The vehicles in Line 5 of Guangzhou metro are driven by linear motors , in order to confirm the characteristics of running resistance , out the expanding vehicles''running resistance test was carried on the owner''s line, and the basic running resistance formula of linear motor driving metro vehicle was calculated .The formu-la was compared with the basic running resistance of the traditional rotating motor driving metro vehicles .The re-sults show that the linear motor driving metro vehicle has better characteristics of running resistance , especially the smaller unit running resistance at high speed .

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为了研究双层充气式气动阻力锥二级展开对其力学性能的影响，文章首先基于有限单元方法，利用Newton-Raphson非线性迭代计算方法分析并比较了二级展开前后的气动阻力锥结构充压变形特征，并获取二者最大应力随充气压力的变化规律；然后引入气动阻力锥结构预应力刚化效应，计算预应力下气动阻力锥结构的振动模态；最后，研究二级阻力面展开瞬时对气动阻力锥最大压力、最大温度以及气动阻力等特性的影响。结果表明：气动阻力锥二级展开，在某种程度上会引起结构强度的下降；也导致结构第三阶模态频率降低，使结构更容易受到外界激励而产生颤振，甚至导致结构破坏；但气动阻力锥的二次展开可以使得结构气动阻力增加两倍之多，可保证气动阻力锥安全抵达地面。因此，合理选择二级展开对应的飞行速度可以增加结构的安全性。
In order to study the effect of the secondary deployment of double-layer inflatable aeroshell structure on its mechanical characteristics, first, the pressurized deformation of the structure before and after secondary inflation is analyzed and compared by using the Newton-Raphson iteration method in this paper based on finite element method , and the change of the maximum stresse with the inflation pressure is obtained. Then, based on the pre-stressed stiffening effect of the two inflatable aeroshell structures on the inflation pres-sure, the vibration modes are calculated. Finally, the influence of the secondary inflation on the maximum pressure, maximum temperature and the aerodynamic drag of the flow field around the structure are researched. The results show that both the structural strength and the third modal frequencies of this structure decrease when the structure achieves the secondary inflation, which implies the structures are easier to flutter due to ex-ternal exc

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高速双体船因为其较高的航速以及双体船本身的特性,而与一般的低速船舶有着较大的不同,因此一些适用于低速船舶的阻力估算方法在估算高速双体船阻力时,可能产生较大的误差。论文以一艘550t高速双体船为例,利用不同的阻力估算方法与CFD计算软件,对其阻力进行了预报。分别计算粘性阻力与兴波阻力的方法,其预报结果与试验结果较为接近,更适合高速双体船的阻力估算。
Because of the big difference between high-speed catamaran and low-speed ships, estimation of the resistance of high-speed catamaran with the methods used for low-speed ships will result in a serious error. In this paper various methods and CFD software are applied to calculate the total resistance of a 550t high-speed catamaran and compared with model tests. The method, in which viscous resistance and wave resistance is calculated separately, is more suitable to the estimation of the resistance for high-speed catamaran.

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通过分离涡模拟法(detached eddy simulation,DES)对半潜式钻井服务支持平台拖航阻力进行了研究,重点对平台拖航阻力、阻力系数和平台表面附近流场分布等特性进行了研究.研究表明:流方向下平台各结构所受阻力各不相同,下浮体占据总阻力比最大(尤其是90°来流方向下).阻力系数及升力系数时历曲线变化具有"脉动性".通过平台表面附近流场分布可以分析涡形成及受力原因,逆方向流及涡之间相互作用使得阻力有所减小.
Detached eddy simulation (DES)is applied to research on drag force of semi-submersible tender sup-port vessel.The drag force,drag coefficient,lift coefficient and flow field on surface of the platform are studied in this paper.It is demonstrated that drag force on every structure of the platform varies with the incidence angle of current.Drag force on pontoon accounts for the largest proportion of that on the platform,especially at inci-dence angle of 90.The"beating"behavior appears in the time history of drag coefficient and lift coefficient.The reason of vortex formation and force on surface of platform is discussed in terms of the flow field near the platform surface.Counter current and interaction between vortices can reduce drag force of the platform.

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