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不锈蝙蝠

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[求助] "mean velocity" and "average velocity"? 已有2人参与

Numerous terminologies containing "velocity" exist in Flow Dynamics/Mechanics, among which, one term seems often so similar to another that I could not understand it accurately enough.
As an example, both "mean velocity (distribution)" and "everage velocity" were used in an english reference I'm reading, but with different symbols.
So my question is: what exactly is the difference between these two term? Does "mean velocity" equals to "time-average velocity", as there is a "distribution" following, while "average velocity" means "section-average velocity" which equals to Q/A?

Notes:
1. You are appreciated to answer this post in English.
2. You are greatly appreciated to point out the language erros in my description above.
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不锈蝙蝠

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zhtear99: 回帖置顶 2013-08-23 21:37:25
问题大意:流体动力学中有很多包含“Velocity”的术语,有些相近不易辨别。
最近读文献,同时出现“mean velocity (distribution)”和“average velocity”,且用不同符号表示。
想问一下是否前者是指“时均流速(分布)”而后者则是“断面平均流速”的意思?
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3楼2013-08-23 10:45:30
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chem_boy

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zhtear99: 金币+1, 感谢热心应助,也是一个好建议~ 2013-08-23 21:36:50
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8楼: Originally posted by 不锈蝙蝠 at 2013-08-23 11:30:13
好吧。这个帖子不是求助翻译的,是我尝试用英文提问问题的。问题中文表达见3楼。...

两者字面意思都是平均流速,但具体怎么个平均法只能看具体情况,建议你从他们的计算公式上着手区别。
10楼2013-08-23 14:48:36
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匿名

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16楼2013-12-17 05:47:44
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befair

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My three cents:
In general these two words should be equivalent in our daily life, in which we tend to say average more than mean. In scientific context there are however some distinctions to make. When it comes to data analysis, often average is referred to as arithmetic mean(even moving average), while in statistical terminology mean has a specific meaning, that is the expectation of a distribution. In this case one cannot say average any longer.

To come back to your question, my suggestions are as follows:
1. If you do data analysis "simplistically" on some velocity measurement values without statistical distributions involved, use average should be fine, or use arithmetic mean
2. If you try to model the velocity as a statistical distribution and then use the mean of (theoretical) distribution, I'd suggest you to stick to mean
Hope it helps
Befairorbeaware
17楼2013-12-17 07:16:24
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arleydou

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2楼2013-08-23 10:14:12
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4楼2013-08-23 10:55:53
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liulion2008

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Numerous terminologies containing "velocity" exist in Flow Dynamics/Mechanics, among which, one term seems often so similar to another that I could not understand it accurately enough.
5楼2013-08-23 11:23:34
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liulion2008

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Numerous terminologies containing "velocity" exist in Flow Dynamics/Mechanics, among which, one term seems often so similar to another that I could not understand it accurately enough. 流体动力学专业名词中有太多词语中使用了“速率”这个词语,这些词语的相似程度比较高,我不能很准确的理解这些词语。
6楼2013-08-23 11:25:41
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liulion2008

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As an example, both "mean velocity (distribution)" and "everage velocity" were used in an english reference I'm reading, but with different symbols.例如,我正在阅读的"mean velocity (distribution)" 和"everage velocity",它们的英语表述意思应当相同,而在文章中却用了不同的符号表示(Q/A)。
7楼2013-08-23 11:29:35
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不锈蝙蝠

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引用回帖:
6楼: Originally posted by liulion2008 at 2013-08-23 11:25:41
Numerous terminologies containing "velocity" exist in Flow Dynamics/Mechanics, among which, one term seems often so similar to another that I could not understand it accurately enough. 流体 ...

好吧。这个帖子不是求助翻译的,是我尝试用英文提问问题的。问题中文表达见3楼。
makefulluseofmylife.
8楼2013-08-23 11:30:13
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liulion2008

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So my question is: what exactly is the difference between these two term? Does "mean velocity" equals to "time-average velocity", as there is a "distribution" following, while "average velocity" means "section-average velocity" which equals to Q/A?
我的问题是"mean velocity (distribution)" 和"everage velocity"到底有什么不同。是不是"mean velocity"代表“时间平均速率”,应为后面跟了个"distribution"?而"average velocity"代表"section-average velocity"。到底哪个用Q表示,哪个用A表示,
9楼2013-08-23 11:33:25
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