For this other question "Would this chambered cylinder be possible", preferably near the equator where is a calmest place from the troposphere to the stratosphere where is the windless place one Earth most of the year?
Truth be told, there is no such place. The atmosphere is a fluid, and a fluid moves. If a fluid did not move, it would not be a fluid.
Proof of concept- If you exhale, the carbon dioxide, water vapor, and other materials that form your breath would need to move, otherwise you would asphyxiate. That movement can be classified as wind, therefore wind exists.
Concerning the reference to your other question, there is no such a location. Consider the surface. Usually we assume the surface is fixed, which is fine over solid land. Because of this, there must be drag on the atmosphere. This drag slows the wind down. Since the air closest to the ground is slower than the air a bit further from the ground, there must be shear. Therefore shear is unavoidable.
For this entire monologue, I have spoken only on the small scales. It is worth noting that on the larger scales, that your linked question is true. A feature of geostrophic theory is the existence of Taylor columns. The Great Red Spot on Jupiter can be considered an example of such a Taylor Column (Ingersoll 1969).
Not just the south pole, but 'Ridge A' and many other parts of the high Antarctic Plateau, at or about 4000 metres altitude, are generally recognized as being the least windy. Otherwise, there are a many parts of the high pressure belts at about +/- 30 degrees which have little wind for most of the year. These tend to be very dry deserts where occasional winds have momentum from other regions. On a local scale there are some deep valleys in tropical rain forests. Once you get below the canopy turbulence level they seldom receive winds of any significance - just the lightest breeze from impeded convection. However, records are hard to find because anemometers in such locations are not really representative of anything.
There is an instagram which claims that Fern tree bus stop, in Hobart, Tasmania, is the 'calmest place on Earth'. But my experience of Hobart is that icy winds in winter can be far from calm.
These things are relative. Compared to the 2100 km/hour winds of Neptune, everywhere on our planet is as close to windless as makes no difference.