Editing Wind tunnel (section)

===Environmental wind tunnels===
[[File:Схема ПСА.jpg|thumb|355x355px|A drawing of the test section in an environmental wind tunnel. It shows the velocity profile generated by the test section obstructions. The profile is a simulation of the natural wind boundary layer with height 'H' and turbulent velocity profile 'u'.]]
Wind tunnel tests are used to determine wind velocities around buildings and bridges, and the wind forces on them.<ref>{{cite journal |last1=Chanetz |first1=Bruno |title=A century of wind tunnels since Eiffel |journal=Comptes Rendus Mécanique |date=August 2017 |volume=345 |issue=8 |pages=581–94 |doi=10.1016/j.crme.2017.05.012 |url=https://hal.archives-ouvertes.fr/hal-01570740/file/BCA.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://hal.archives-ouvertes.fr/hal-01570740/file/BCA.pdf |archive-date=2022-10-09 |url-status=live |bibcode=2017CRMec.345..581C |doi-access=free }}</ref>

Environmental wind tunnels are used to simulate the boundary layer of the atmosphere in windy conditions near the earth's surface. The wind near the ground is highly turbulent.<ref>{{cite book |title=Micrometeorology; A Study Of Physical Processes In The Lowest Layers Of the Earth's Atmosphere| url=https://archive.org/details/micrometeorology0000sutt/page/n7/mode/2up|author1=Sutton, O. G.(Oliver Graham) |date=1953|publisher=McGraw-Hill |location=New York |page=[https://archive.org/details/micrometeorology0000sutt/page/56/mode/2up 56]}}</ref> Whereas vehicle wind tunnels have features to produce steady, straight-line air approaching the test model environmental tunnels need spires followed by small cubes on the floor to make the air represent the atmosphere boundary layer as it approaches the test object.<ref>{{cite book|url=https://www.academia.edu/35129053/LOW_SPEED_WIND_TUNNEL_TESTING_THIRD_EDITION_A_WILEY_MTERSCIENCE_PUBLICATION|title=Environmental Wind Tunnel Testing|author1=Kumar, Sathis|publisher=Wiley-Mter Science Publication|edition=Third |page=4}}</ref> The forces caused by wind on high-rise buildings and bridges have to be understood so they can be built using a minimum of construction materials while still being safe in very high winds. Another significant application for boundary layer wind tunnel modeling is for understanding exhaust gas dispersion patterns for hospitals, laboratories, and other emitting sources. Other examples of boundary layer wind tunnel applications are assessments of pedestrian comfort and snow drifting. Wind tunnel modeling is accepted as a method for aiding in [[green building]] design. For instance, the use of boundary layer wind tunnel modeling can be used as a credit for [[Leadership in Energy and Environmental Design]] (LEED) certification through the US Green Building Council.