什么是流体的粘滞性？
What is the viscosity of a fluid?
粘滞性描述流体内部因分子间作用而产生的内摩擦，使不同速度层之间互相阻碍。蜂蜜粘滞性高、水流粘滞性低，雷诺数用来判断流动形态。
Viscosity describes the internal friction in a fluid from molecular interactions that resists relative motion between layers. Honey has high viscosity and water low; the Reynolds number predicts flow type.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 4 条独立证据
来源 · Source
Halliday, Resnick, Walker,《Fundamentals of Physics》第10版,Wiley,2013
David Halliday, Robert Resnick, Jearl Walker, Fundamentals of Physics, 10th ed., Wiley, 2013
独立核验依据 · Independent verification: 核验依据 3 angusrobertson.com.au
#粘滞性 #内摩擦 #雷诺数
层流和湍流有什么区别？
What is the difference between laminar and turbulent flow?
层流中流线平行、各层互不混合，流动平稳；湍流则混乱翻滚、充满涡旋，能量损耗大。雷诺数较小通常对应层流，较大则转为湍流。
In laminar flow streamlines are parallel and layers do not mix, giving smooth motion; turbulent flow is chaotic with eddies and high energy loss. Low Reynolds number means laminar flow, high means turbulent.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 4 条独立证据
来源 · Source
Halliday, Resnick, Walker,《Fundamentals of Physics》第10版,Wiley,2013
David Halliday, Robert Resnick, Jearl Walker, Fundamentals of Physics, 10th ed., Wiley, 2013
独立核验依据 · Independent verification: 核验依据 3 angusrobertson.com.au
#层流 #湍流 #雷诺数
什么是湍流的能量级串？柯尔莫戈罗夫理论如何解释惯性区的 -5/3 能谱？
What is the energy cascade in turbulence, and how does Kolmogorov theory explain the -5/3 spectrum in the inertial range?
高雷诺数下，动能自大尺度含能涡注入，经非线性作用逐级传给更小的涡，直至黏性尺度耗散为热，此即能量级串。柯尔莫戈罗夫 1941 年指出：远离边界的小尺度湍流统计仅由平均耗散率 ε 决定，故惯性区内能谱呈 E(k)∝ε^(2/3)k^(-5/3) 幂律，实验与数值模拟均已广泛验证。
At high Reynolds number, kinetic energy is injected into large energy-containing eddies, handed down through nonlinear interactions to ever smaller eddies, and finally converted to heat by viscosity at the smallest scales — this is the energy cascade. Kolmogorov argued in 1941 that small-scale turbulence statistics far from boundaries depend only on the mean dissipation rate per unit mass ε; in the inertial range between the energy-containing and dissipative scales the spectrum becomes E(k) ∝ ε^(2/3) k^(-5/3), a law extensively confirmed by experiments and direct numerical simulations.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03
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A. N. Kolmogorov, The local structure of turbulence in incompressible viscous fluid for very large Reynolds numbers, Dokl. Akad. Nauk SSSR 30, 301 (1941)；英译本 Proceedings of the Royal Society of London A 434, 9-13 (1991), DOI: 10.1098/rspa.1991.0075
A. N. Kolmogorov, Dokl. Akad. Nauk SSSR 30, 301 (1941); English translation in Proceedings of the Royal Society of London A 434, 9-13 (1991), DOI: 10.1098/rspa.1991.0075
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1098/rspa.1991.0075：The local structure o
#流体与湍流 #能量级串 #柯尔莫戈罗夫谱
伯努利原理是什么？
What is Bernoulli's principle?
伯努利原理指出，在理想流体中流速越大的地方压强越小。飞机的机翼上表面流速快、压强低，从而产生向上的升力。
Bernoulli's principle says that in an ideal fluid, faster flow means lower pressure. An airplane wing has faster flow and lower pressure on top, creating upward lift.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 4 条独立证据
来源 · Source
Halliday, Resnick, Walker,《Fundamentals of Physics》第10版,Wiley,2013
David Halliday, Robert Resnick, Jearl Walker, Fundamentals of Physics, 10th ed., Wiley, 2013
独立核验依据 · Independent verification: 核验依据 3 angusrobertson.com.au
#伯努利原理 #压强 #流速
什么是表面张力？
What is surface tension?
表面张力是液体表面因分子间引力而像一层弹性薄膜的现象，使水珠呈球形、小虫能在水面行走。它由液体表面分子受内部分子吸引不平衡造成。
Surface tension is the liquid surface behaving like an elastic film due to intermolecular attraction, making drops spherical and letting some insects walk on water. It arises from unbalanced pulls on surface molecules.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 4 条独立证据
来源 · Source
Halliday, Resnick, Walker,《Fundamentals of Physics》第10版,Wiley,2013
David Halliday, Robert Resnick, Jearl Walker, Fundamentals of Physics, 10th ed., Wiley, 2013
独立核验依据 · Independent verification: 核验依据 3 angusrobertson.com.au
#表面张力 #液体 #分子引力
水管里的水什么时候从“顺滑”变成“乱搅”？
When does water in a pipe switch from smooth to churning?
由雷诺数 Re=ρvD/μ 决定：Re 小是平顺的层流，Re 大到约 2000 以上逐渐转为混乱的湍流。黏度小、管粗、流速快都更容易起湍流。
The Reynolds number Re=ρvD/μ decides it: low Re is smooth laminar flow, and above roughly 2000 it drifts into chaotic turbulence. Low viscosity, wide pipes, and high speed all favor turbulence.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Reynolds,《XXIX. An experimental investigation of the circumstances which determine whether the motion of water shall be direct or sinuous, and of the law of resistance in parallel channels》,Philosophical Transactions of the Royal Society of London,1883 (DOI: 10.1098/rstl.1883.0029)
Reynolds, 'XXIX. An experimental investigation of the circumstances which determine whether the motion of water shall be direct or sinuous, and of the law of resistance in parallel channels', Philosophical Transactions of the Royal Society of London, 1883, DOI: 10.1098/rstl.1883.0029
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1098/rstl.1883.0029
#雷诺数 #层流 #湍流
为什么小水珠是圆球状，小虫能在水面走？
Why are water drops round and some insects walk on water?
水分子相互吸引，表面想缩到最小面积，于是水珠成球；这层“皮”就是表面张力，足以托住比水轻、脚不刺破水膜的小虫。
Water molecules attract, so the surface pulls to the smallest area and a drop becomes a sphere; that skin is surface tension, strong enough to hold light insects whose feet don't pierce the film.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
G. K. Batchelor 著《An Introduction to Fluid Dynamics》（流体动力学导论）
G. K. Batchelor, An Introduction to Fluid Dynamics
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780521041188 (1973)
#表面张力 #水滴 #毛细
阿基米德原理说的是什么？
What does Archimedes' principle state?
阿基米德原理指出，浸入流体中的物体所受浮力等于它排开流体的重力。这解释了为什么大船能浮起，也用于测量物体的密度。
Archimedes' principle says the buoyant force on an immersed object equals the weight of the fluid it displaces. It explains why huge ships float and is used to measure density.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 4 条独立证据
来源 · Source
Halliday, Resnick, Walker,《Fundamentals of Physics》第10版,Wiley,2013
David Halliday, Robert Resnick, Jearl Walker, Fundamentals of Physics, 10th ed., Wiley, 2013
独立核验依据 · Independent verification: 核验依据 3 angusrobertson.com.au
#阿基米德原理 #浮力 #排开
为什么大船用钢铁造，却不会沉？
Why doesn't a big steel ship sink?
船体空心的部分排开很多水，水给的浮力等于船排开水的重量。只要浮力不小于船重，船就浮着；钢铁虽重，但摊开成空心就轻于同体积的水。
A hollow hull displaces a lot of water, and the water pushes up with a force equal to that water's weight. As long as buoyancy beats the ship's weight, it floats; steel is heavy but spread into a hollow shape it's lighter than the water it displaces.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录仅给书名，无版次与年份；同一书名常对应多个版次，不臆测具体版本。
Archimedes（阿基米德）, 《On Floating Bodies》（论浮体）, c. 250 BC
Archimedes, On Floating Bodies (c. 250 BC)
#浮力 #排开水 #阿基米德
什么是浮力？
What is buoyancy?
浮力是流体对浸入其中的物体向上的托力。当浮力大于或等于物体重力时，物体就能浮在液体表面或悬在水中。
Buoyancy is the upward force a fluid exerts on an immersed object. When buoyancy equals or exceeds the object's weight, it floats on or is suspended in the liquid.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 4 条独立证据
来源 · Source
Halliday, Resnick, Walker,《Fundamentals of Physics》第10版,Wiley,2013
David Halliday, Robert Resnick, Jearl Walker, Fundamentals of Physics, 10th ed., Wiley, 2013
独立核验依据 · Independent verification: 核验依据 3 angusrobertson.com.au
#浮力 #流体 #托力
用管子怎么把水从高处“抬”过杯沿再流到低处？
How can a tube carry water up over a rim and down to a lower place?
这是虹吸：先把管里灌满水，低处那端因水柱更重把水持续拉下，高处的水被带着翻过杯沿。前提是出口低于液面、中间不能进空气。
That's a siphon: fill the tube, and the longer, lower column pulls water down continuously, drawing the higher water over the rim. The outlet must sit below the surface and no air can break in.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Serway & Jewett,《Physics for Scientists and Engineers》第9版,Cengage Learning,2013
R. A. Serway and J. W. Jewett, Physics for Scientists and Engineers, 9th ed., Cengage Learning, 2013
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-1-337-55327-8
#虹吸 #压强 #液面
什么是大气压强？
What is atmospheric pressure?
大气压强是地球大气层因自身重力而对地面物体施加的压强，海平面处约为 101 千帕。我们感觉不到它，是因为体内外压强相互平衡。
Atmospheric pressure is the force per area the air's weight exerts on objects, about 101 kilopascals at sea level. We do not feel it because internal and external pressures balance.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
气体压强常识
Common knowledge of gas pressure
#大气压 #压强 #空气