查看“︁哈特曼數”︁的源代码

'''哈特曼數''' （Hartmann number，Ha) 是電磁力和黏滯力之間的[[無因次量]]，最早是由[[丹麦]]物理學家朱利叶斯·哈特曼（Julius Hartmann,1881-1951）開始使用<ref>{{cite book|author=Kenneth R.Cramer, Shih-l Pai| title=Magnetofluid Dynamics for Engineers and Applied Physicists|url=https://archive.org/details/magnetofluiddyna0000cram| publisher=Scripta Publishing Company| year=1973 |isbn=0-07-013425-1}}</ref><ref>R. Moreau u. a.:[http://www.springerlink.com/content/h72135131418n257/ ''Julius Hartmann and His Followers: A Review on the Properties of the Hartmann Layer.'']{{Dead link|date=2020年2月 |bot=InternetArchiveBot |fix-attempted=yes }} In: ''Magnetohydrodynamics'' Springer Netherlands, 2007, S.&nbsp;155–170. ISBN 978-1-4020-4832-6</ref>，在探討磁性流體的流動時常會使用此無因次量<ref>{{cite book|author=Cramer|first=Kenneth R.|title=Magnetofluid Dynamics for Engineers and Applied Physicists|url=https://archive.org/details/magnetofluiddyna0000cram|last2=Pai|first2=Shih-i|publisher=Scripta Publishing Company|year=1973|isbn=0-07-013425-1|lccn=73009936}}</ref>。定義為：

: <math>\mathrm{Ha} = B L\sqrt{\frac{\sigma} {\mu}}</math>
其中
* ''B'' 為系統的[[磁場]]
* ''L'' 為系統的特徵長度
* ''&sigma;'' 為[[導電率]]
* ''&mu;'' 為[[動黏度]]

另一個無因次量{{le|錢德拉塞卡數|Chandrasekhar number}}（Chandrasekhar number）Q也和此無因次量有關。

:: <math> Q\ {=}\ Ha^2\ </math>

錢德拉塞卡數是得名自印度[[天体物理学]]家[[苏布拉马尼扬·钱德拉塞卡]]。
==相關條目==
* [[斯图尔特数]]
* [[磁流體力學]]

==參考資料==
{{reflist}}

==延伸閱讀==
* {{Cite book|last=Jackson|first=J.D.|title=Classical Electrodynamics|publisher=John Wiley & Sons|year=1975|isbn=0-471-43132-X|edition=Second|chapter=Magnetohydrodynamics and Plasma Physics|lccn=75009962|access-date=2020-05-16|chapter-url=https://archive.org/stream/ClassicalElectrodynamics2nd#page/n495/mode/2up}}，其中的哈特曼數標示為M，類似空氣動力學的[[馬赫數]]。
* P. Kurzweil: ''Das Vieweg Formel-lexikon.'' Vieweg+Teubner, 2002, S.&nbsp;314 ISBN 3-528-03950-7.
* Carl W. Hall, Laws and Models:Science, Engineering and Technology, Boca Ratón, CRC Press, 2000, 524 p. (ISBN 8449320186).
* Bernard Stanford Massey, Measures in science and engineering : their expression, relation and interpretation, Ellis Horwood Limited, 1986, 216 p. (ISBN 0853126070).

{{NonDimFluMech}}
{{流體動力學小作品}}
[[Category:流體力學中的無因次量]]
[[Category:流體動力學]]
[[Category:磁流体力学]]