[freebeard]

en.wikipedia.org/wiki/Poul_la_Cour

Denmark is blessed with a lot of wind, and at a time where electricity was about to be introduced in Denmark, la Cour felt that the wind should contribute to the electrification of the country. In the Netherlands, the idea of electrification by means of windmills had been investigated with negative conclusions, because of their low efficiency, and the problems of storing energy . But these problems had appealed to the inventor and physicist la Cour. In 1891 he got the idea of storing wind as hydrogen (and oxygen) energy by passing the electricity through water and using electrolysis. He was granted financial support by the Danish Government, and the first experimental mill at Askov was erected in the summer of 1891. La Cour's first task however was to "tame" the wind power, in order to make the mill produce a constant power in order to drive a generator. This was solved by the so-called Kratostate, a differential regulator, which later was simplified ("vippeforlaget") and widely used in electricity producing windmills in the Nordic countries and Germany.
[snip]
Traditional wisdom considered the action of wind on the wings as an impulse of particles, which made Newtonian calculations possible. Although Daniel Bernoulli and Leonhard Euler had laid the foundation of modern fluid dynamics a hundred years earlier this had had no consequence for such complicated practical problems as that of the action of wind on wings; and in the cases where a computation was possible, theory did not match experience (Paradox of d'Alembert). The union of theory and experiment came mainly through careful wind tunnel experiments. The Danish tradition in this area was started by H. C. Vogt and Johan Irminger in the early 1890s. La Cour continued in 1896 when he started to test small models of windmills in a wind tunnel, probably the first such experiments in the world focusing on windmills.

Oh yeah, the picture


https://ing.dk/artikel/poul-la-cour-...storien-186128

The only tunnel pictures I find are a new one built with his name on it.