dynamic soaring

Ralph Jones wrote:
...
The most interesting conclusion is that if the curl is the only source
of energy (in other words, there is no vertical velocity component to
complicate the issue), the optimum strategy is amazingly simple. Most
of the variables fall right out of the calculation, and the result is:
Circle in a 55-degree bank. Go to the left if the curl direction is
upward, right if it's downward.
...

But in the case of wind shear discussed here as mentionned on the
site quoted in the first post of this discussion, the curl direction
is horizontal, perpendicular to the direction of the wind.