When I get a respectful answer, I give a respectful answer:
We are talking about how that system is modified by extracting energy from it as reduced velocity, and because that can impact moisture take up it is also a question of how that impacts cloud formation. That change is permanent since the energy does not reinvent Something ends up colder (micro property) or wind velocity lower (macro property). Worsecan be the feedback:
Anything that can mess with cloud formation changes the impacted energy so like a heatpump can cause a change out of all proportion to stimulus.
Anyone who ever analyzed weather patterns knows small changes in initial condition can make massive changes in pattern development..
We had problems with it every time it was part of our work: radar propagation , on structure distortion in high winds and on modelling a vortex shedding flow meter.
Proof of that: If you look at the app "weather radar" you can often see a totally different prognosis for the "today" cast from the "Now cast" when referring to exactly the same time. And if they are not different just look at a different weather app, and there will be big differences in low pressure propagation of weather, so big difference in forecast
So it doesnt take much to have influence.
And that is my worry - we are rushing headlong into something ill understood.
Here is my worry: A paper written by industry funded directly by the offshore windmill industry , or by those with vested interest to say "all is well", in a sector where political factors dont want there to be a problem, is not going to conclude "problem" since it is unlikely to look very hard for problems!.
If they had asked inseteda "then what has been changed by windmills because something MUST have done, either micro or macro, they then might have found where the energy deficit manifests. A matter of asking the right questions.
Reality is as the propagation occurs over long distance the difference become immeasurable not least because noticing whehter anything has changed depends on comparing a base line, and the base line for this is a hard problem because no two times are really comparable.
You say "no evidence".
Very Early on in this conversation I pointed out that there are those who speculate that offshore windfarms can divert the path of and development of hurricanes in gulf of mexico. A paper was written somewhere. The industry cannot have it both ways. No impact vs mega impact.
Oh the irony overload of claiming you provide respectful answers, this is the sort of comment Don Quixote’s sidekick Manuel Doltote would make.
Here is some very basic fluid mechanics in the hope to you might actually learn something.
First of all wind in the form of a stream tube is modelled as a cylinder.
One of the most basic equations used in fluid mechanics is the continuity equation which is the conservation of mass and states the mass flow rate entering the cylinder equals the mass flow rate exiting the cylinder.
Mass flow rate = ρV/t
Where ρ is the density of the fluid, V is the volume and t is the time.
For low wind speeds, air can be considered to be an incompressible fluid hence ρ is constant.
Rewriting the mass flow rate = ρV/t = ρAxv/x = ρAv
Where v is the flow velocity, A is the cross-sectional area and x is the length of the cylinder.
The only thing you seem to comprehend in this thread is the velocity of the downstream wind tube is less than the velocity of the upstream wind tube.
The continuity equation still applies when the wind goes through the turbine.
The mass flow rate for the upstream wind tube = ρA₁v₁.
The mass flow rate for the downstream wind tube = ρA₂v₂.
Hence ρA₁v₁ = ρA₂v₂
A₂ = A₁v₁/v₂
Since v₂ < v₁, A₂ > A₁
The diameter of the upstream wind tube can be no larger than the diameter swept out by the rotor blades hence for a windmill which reduces the wind velocity by 50% the diameter of the downwind stream tube is doubled.
What all of this means is that the scene of the action is at or near ground level for both temperature change and on the rare occasions the formation of wake clouds near the surface and is far divorced from your global effects.
Secondly is this nonsense of wind effects being permanent.
If you had even the vaguest comprehension of fluid mechanics you would be aware of the role of Reynolds number Re and how it totally destroys your argument.
Re = puL/μ
ρ is the density of the fluid, u is the flow speed, L is a characteristic length and μ is the dynamic viscosity of the fluid.
As has been explained previously upstream wind has a low Reynolds number and as the diagram shows can be modelled as having a laminar flow where the velocity profile increases with increasing distance from the ground.
Wind going through the turbine has a very high Reynolds number dominated by turbulent flow which results in the following.
(1) The formation of vortices and eddies, regions of high TKE (turbulent kinetic energy), which breakdown to a larger number at smaller scales where TKE is conserved. The process continues until a scale is reached where the action of viscous forces results in converting the TKE of the smallest vortices and eddies into heat which explains the temperature variations at and near the surface.
(2) Turbulence mixing of the downwind stream tube with the external environment eventually eliminates the velocity deficit.
Thirdly and most importantly is the evidence presented in this thread which shows the velocity deficit declines with distance before disappearing.
Ignoring the evidence is not how a professional scientist would react, a crank clinging onto a pet theory is a more accurate description.
