Numerical Analysis of Air Flow in a Modular Fan Unit Using CFD Simulation Petr Zelenský, Martin Barták, Vojtìch Zavøel, Vladimír Zmrhal and Radislav Krupa E3S Web Conf., 111 (2019) 01008 Published online: 13 August 2019 DOI: 10.1051/e3sconf/201911101008