Geometrical optimization of a rocking bioreactor for efficient mixing and oxygen transport

Rocking or wave-mixed bioreactors have recently been proposed as a promising innovation for the production of cultivated meat. Unlike other types of bioreactors, they are disposable, require low operating expenses, and are simple to scale up. However the performance of the rocking bioreactor is not well characterized due to a wide range of geometrical and operating parameters, and its short history in market. In the present study we quantitatively evaluate mixing within a rocking bioreactor with different geometries and operating conditions based on an implementation in the Basilisk open-source platform. We use the second-order finite volume Navier-Stokes solver and a volume-of-fluid interface reconstruction method to accurately resolve the highly nonlinear fluid motion. We additionally solve the advection-diffusion equation for soluble tracers to compute the degree of mixing. In particular, we investigate the dependence of mixing times on the aspect ratio in simplified elliptical geometries. Our results are expected to provide guidelines for designing optimized bioreactors for next generation cultivated meat industry design pipelines.