“…Flasks are available in different sizes and materials, baffled, non-baffled and with other additions such as spring coils inserted at the bottom of the flask (Hopwood et al, 1985). These designs are used for different bioprocess development projects (Suresh et al, 2009), and therefore, many studies have been conducted on flasks since this shaking process was introduced into the biotechnology field at the beginning of the previous century. Different aspects of shaken Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ces flasks have been investigated (Freedman, 1970;B眉chs et al, 2000a, b;Hansen et al, 2011;Kl枚ckner and B眉chs, 2012); however, only few studies provide complete information of the inside flow.…”