Edit DefineConcept: Anisotropic turbulence

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 Velocity point-measurements  Velocity profilers  Shear probes

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Other media include images. The text will appear below the required info above. A state whereby the velocity components and their derivatives are dependent on direction. If this is not the case the turbulence is said to be [[isotropic_turbulence|isotropic]]. Taylor makes the statement "That there is a strong tendency to [[isotropic turbulence|isotropy]] in turbulent motion has long been known. It has been shown by Townend,<ref>Townend, H.C.H., 1934. Statistical measurements of turbulence in the flow of air through a pipe. Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 145(854), pp.180-211 (highly recommended for a look at early optical approaches to quantifying turbulence).</ref> for instance, that the average values of the three components of velocity in the central region of a pipe of square section are nearly equal to one another<ref>Taylor, G. I. (1935). Statistical theory of turbulence. Proceedings of the Royal Society of London. Series A-Mathematical and Physical Sciences, 151(873), 421-444. https://doi.org/10.1098/rspa.1934.0090</ref>" A natural consequence of this is the large body of work on anisotropy in boundary-layer flows. However, stratification also influences the degree of isotropy. Taylor then goes on to say "in the atmosphere the same phenomenon has been observed; though, as might be expected, the vertical components are smaller near the ground than the horizontal ones, this inequality decreases with height above the ground." The [[Nomenclature#Theoretical_Length_and_Time_Scales|Ozmidov Lengthscale]] is the largest scale for stationary homogeneous isotropic turbulence and is defined <math>L_o=\left(\frac{\varepsilon}{N^3}\right)^{1/2}</math>. Overturns greater than the Ozmidov lengthscale are partially suppressed by density stratification as defined by [[Nomenclature#Fluid_properties_and_background_gradients_for_turbulence_calculations|buoyancy frequency]] <math>N</math> and isotropy is impeded <ref>Kunze, E., 2019. A unified model spectrum for anisotropic stratified and isotropic turbulence in the ocean and atmosphere. Journal of Physical Oceanography, 49(2), pp.385-407. https://doi.org/10.1175/JPO-D-18-0092.1</ref>. ==Notes==

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