Pluriharmonic function: Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
Newer edit →
en>ChrisGualtieri
m TypoScan Project / General Fixes, typos fixed: , → , using AWB
 
en>Addbot
m Bot: Migrating 1 interwiki links, now provided by Wikidata on d:q4365897
Line 1: Line 1:
Andera is what you can contact her but she by no means truly favored that name. North Carolina is the place he enjoys most but now he is contemplating other options. Distributing manufacturing is how he makes a residing. The preferred hobby for him and his children is to play lacross and he'll be beginning  [http://breenq.com/index.php?do=/profile-1144/info/ online psychic reading] clairvoyant psychic ([http://www.onbizin.co.kr/xe/?document_srl=320614 www.onbizin.co.kr]) some thing else along with it.<br><br>Feel free to surf to my web site: psychic chat online ([http://ustanford.com/index.php?do=/profile-38218/info/ http://ustanford.com])
'''Roughness length''' (<math>z_0</math>), is a [[parameter]] of some vertical wind profile equations that model the horizontal mean wind speed near the ground; in the [[log wind profile]], it is equivalent to the height at which the wind speed theoretically becomes zero. In reality the wind at this height no longer follows a mathematical logarithm. It is so named because it is typically related to the height of terrain roughness elements. Whilst it is not a physical length, it can be considered as a length-scale a representation of the roughness of the surface.
 
As an approximation, the roughness length is approximately one-tenth of the height of the surface roughness elements. For example, short grass of height 0.01m has a roughness length of approximately 0.001m. Surfaces are rougher if they have more protrusions. Forests have much larger roughness lengths than tundra, for example. Roughness length is an important concept in [[urban meteorology]] as the building of tall structures, such as skyscrapers, has an effect on roughness length and wind patterns.
 
{|
|Terrain description
|<math>z_0</math> (''m'')
|-
|Open sea, [[Fetch (geography)|Fetch]] at least 5 km
|0.0002
|-
|Mud flats, snow; no vegetation, no obstacles
|0.005
|-
|Open flat terrain; grass, few isolated obstacles
|0.03
|-
|Low crops; occasional large obstacles, ''x/H'' > 20
|0.10
|-
|High crops; scattered obstacles, 15 < ''x/H'' < 20
|0.25
|-
|parkland, bushes; numerous obstacles, ''x/H'' ≈ 10
|0.5
|-
|Regular large obstacle coverage (suburb, forest)
|1.0
|-
|City centre with high- and low-rise buildings
|≥ 2
|}<ref>WMO Guide to Meteorological Instruments and Methods of Observation WMO-No. 8 page I.5-12</ref>
 
 
 
==References==
{{reflist}}
 
==External links==
* [http://amsglossary.allenpress.com/glossary/search?id=aerodynamic-roughness-length1 Aerodynamic Roughness (Length AMS Glossary)]
* [http://www.webmet.com/met_monitoring/663.html Surface Roughness Length]
* [http://www-das.uwyo.edu/~geerts/cwx/notes/chap14/roughness.html Roughness]
* [http://amsglossary.allenpress.com/glossary/search?id=roughness-length1 Roughness (AMS Glossary)]
 
==See also==
*[[Von Kármán constant]]
*[[Monin-Obukhov length]]
*[[Wind profile power law]]
*[[Log wind profile]]
*[[Displacement height]]
 
[[Category:Atmospheric dispersion modeling]]
[[Category:Fluid dynamics]]
 
 
{{climate-stub}}

Revision as of 15:16, 14 March 2013

Roughness length (z0), is a parameter of some vertical wind profile equations that model the horizontal mean wind speed near the ground; in the log wind profile, it is equivalent to the height at which the wind speed theoretically becomes zero. In reality the wind at this height no longer follows a mathematical logarithm. It is so named because it is typically related to the height of terrain roughness elements. Whilst it is not a physical length, it can be considered as a length-scale a representation of the roughness of the surface.

As an approximation, the roughness length is approximately one-tenth of the height of the surface roughness elements. For example, short grass of height 0.01m has a roughness length of approximately 0.001m. Surfaces are rougher if they have more protrusions. Forests have much larger roughness lengths than tundra, for example. Roughness length is an important concept in urban meteorology as the building of tall structures, such as skyscrapers, has an effect on roughness length and wind patterns.

Terrain description z0 (m)
Open sea, Fetch at least 5 km 0.0002
Mud flats, snow; no vegetation, no obstacles 0.005
Open flat terrain; grass, few isolated obstacles 0.03
Low crops; occasional large obstacles, x/H > 20 0.10
High crops; scattered obstacles, 15 < x/H < 20 0.25
parkland, bushes; numerous obstacles, x/H ≈ 10 0.5
Regular large obstacle coverage (suburb, forest) 1.0
City centre with high- and low-rise buildings ≥ 2

[1]


References

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

External links

See also


Hello, I'm Willard, a 30 year old from Capodimonte, Italy.
My hobbies include (but are not limited to) Photography, Equestrianism and watching 2 Broke Girls.

Feel free to visit my webpage Hostgator Voucher

  1. ↑ WMO Guide to Meteorological Instruments and Methods of Observation WMO-No. 8 page I.5-12
Retrieved from "https://en.formulasearchengine.com/index.php?title=Pluriharmonic_function&oldid=10664"