I would imagine that at higher density shear makes the profile more vertical?
Thanks!
Is there an equation that describes this? Or how the profile scale (to density, root density density to the power of 'x'?)
Cheers
a
The minimum wind velocity initiating particle movement is known as the threshold velocity. Particle susceptibility to wind erosion is affected by size, density, and shape that influence the wind velocity.
Air density is directly proportional to air pressure. What scenarios are you discussing? Episodical conditions?
Good article. Please review the following link:
http://www.emd.dk/files/windpro/WindPRO_AirDensity.pdf
Density is directly proportional to pressure and indirectly proportional to temperature. As pressure increases, with temperature constant, density increases. Conversely when temperature increases, with pressure constant, density decreases.
Thanks for all the replies; however, I should have been clearer: the wind profile is often taken as going from the boundary (turbulent) zone to the standard 10 m height wind speed. If density were, say, doubled to about 2 bar, how would the profile be altered: does it scale to density, (root) density, density to the power of 'x' ??
I think, in that case wind profile had much to do with the surface roughness factor rather than air density. Since you are not changing air density with height, 10m, wind profile will not be affected.
If you are talking about wind profiles on similar surface at different elevations, then I suggest you inspect the wind profiles of two locations at different attitudes with same surface features. That way the varying elevations wherein the atmospheric pressure (and ofcourse the air density) are different will give you the effect of air density on wind profile.
To be fair, I never thought about it before so can't help you with the straight forward answer. All the best!
Ok
According to
https://www.engineeringtoolbox.com/dynamic-absolute-kinematic-viscosity-d_412.html
Dynamic (absolute) Viscosity
Absolute viscosity - coefficient of absolute viscosity - is a measure of internal resistance. Dynamic (absolute) viscosity is the tangential force per unit area required to move one horizontal plane with respect to an other plane - at an unit velocity - when maintaining an unit distance apart in the fluid.
The shearing stress between the layers of a non turbulent fluid moving in straight parallel lines can be defined for a Newtonian fluid as Viscosity.
This is expressed in the SI system as units of N s/m2, Pa s or kg/(m s)
such that if mass is doubled then this value is also doubled, thus the profile could be expected to also scale as Patm.
Well this is true for Newtonian fluids. Air can be assumed to be Newtonian (may be) for such calculations (though you have to check) but you have to derive a suitable scaling factor.
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