Ground parameters of working standard of reproduction of small speeds of air stream Mykhailo Dudnyk, Viktor Veretennyk, Serhii Enhel, Vadym Krytskyi and Vadym Myroshnychenko E3S Web Conf., 109 (2019) 00021 Published online: 09 July 2019 DOI: 10.1051/e3sconf/201910900021