Mode decomposition and Lagrangian structures of the flow dynamics in orbitally shaken bioreactors

Abstract

In this study, two mode decomposition techniques were applied and compared to assess the flow dynamics in an orbital shaken bioreactor (OSB) of cylindrical geometry and flat bottom: proper orthogonal decomposition and dynamic mode decomposition. Particle Image Velocimetry (PIV) experiments were carried out for different operating conditions including fluid height, h, and shaker rotational speed, N. A detailed flow analysis is provided for conditions when the fluid and vessel motions are in-phase (Fr = 0.23) and out-of-phase (Fr = 0.47). PIV measurements in vertical and horizontal planes were combined to reconstruct low order models of the full 3D flow and to determine its Finite-Time Lyapunov Exponent (FTLE) within OSBs. The combined results from the mode decomposition and the FTLE fields provide a useful insight into the flow dynamics and Lagrangian coherent structures in OSBs and offer a valuable tool to optimise bioprocess design in terms of mixing and cell suspension.

Measurement of interfacial wave dynamics in orbitally shaken cylindrical containers using ultrasound pulse-echo techniques

“…In that regime the liquid distribution at the tank wall is in opposition to the inertial forces. That phenomenon is also well known from orbitally shaken bioreactors, where the phase shift was found to significantly influence the flow fields and the mixing of the flow (Weheliye et al 2018). This predicted phase shift could be verified by different experiments in the regions sufficiently far away from the resonance frequency.…”

“…These bioreactors are of particular interest for fluid dynamists since they offer a high potential for optimization in terms of mixing efficiency and power consumption. Various properties as the influence of different characterized wave and flow regimes to the mixing efficiency, the mass transport or shear stress distributions were numerically and experimentally studied by Weheliye et al (2012); Ducci and Weheliye (2014); Reclari et al (2014); Bouvard et al (2017); Weheliye et al (2018); Alpresa et al (2018a,b). Some of their findings can be directly transferred to interfacial wave systems, as we will discuss in Sect.…”

Selecting the best piping arrangement for scaling-up an annular channel reactor: An experimental and computational fluid dynamics study

“…The POD capability to extract coherent structures, which exhibit patterns in space and also in time, is particularly relevant in mixers, because these structures are the basis of the mixing mechanisms: folding and stretching of fluid elements [7,8] . POD has been applied to chemical engineering in the analysis of stirred tanks [9][10][11][12] and recently orbitally shaken reactors [13] .…”

Study on mixing characteristics in shaken microwell systems

“…Due to the prevalence of STRs in the chemical and biochemical industries, several studies can be found in the literature that provide a thorough investigation of their mixing and fluid dynamics characteristics for a broad range of operating conditions [1, 2,3,4,5,6]. In recent years, the engineering characterisations of labscale OSRs have also been conducted by various researchers in terms of flow dynamics [7,8,9,10,11,12], free surface motion [13,14], solids suspension [15,16] and power consumption [17,18,19], both experimentally and numerically.…”