Optimization of mixing strategy in microalgal raceway ponds

by   Olivier Bernard, et al.

This paper focuses on mixing strategies to enhance the growth rate in an algal raceway system. A mixing device, such as a paddle wheel, is considered to control the rearrangement of the depth of the algae cultures hence the light perceived at each lap. The dynamics of the photosystems after a rearrangement is accounted for by the Han model. Our approach consists in considering permanent regimes where the strategy is parametrized by a permutation matrix which modifies the order of the layers at the beginning of each lap. It is proven that the dynamics of the photosystems is then periodic, with a period corresponding to one lap of the raceway whatever the order of the considered permutation matrix is. An objective function related to the average growth rate over one lap is then introduced. Since N ! permutations (N being the number of considered layers) need to be tested in the general case, it can be numerically solved only for a limited number of layers. Consequently, we propose a second optimization problem associated with a suboptimal solution of the initial problem, which can be determined explicitly. A sufficient condition to characterize cases where the two problems have the same solution is given. Some numerical experiments are performed to assess the benefit of optimal strategies in various settings.



There are no comments yet.


page 20


Mixing strategies combined with shape design to enhance productivity of a raceway pond

This paper focuses on mixing strategies and designing shape of the botto...

Velocity of viscous fingers in miscible displacement

The paper investigates the linear growth of the mixing zone during polym...

The Bahadur representation for sample quantiles under dependent sequence

On the one hand, we investigate the Bahadur representation for sample qu...

Trilevel and Multilevel Optimization using Monotone Operator Theory

We consider rather a general class of multi-level optimization problems,...

Shape optimization of a microalgal raceway to enhance productivity

We consider a coupled physical-biological model describing growth of mic...

The influence of initial perturbation power spectra on the growth of a turbulent mixing layer induced by Richtmyer-Meshkov instability

This paper investigates the influence of different broadband perturbatio...

Alternative Restart Strategies for CMA-ES

This paper focuses on the restart strategy of CMA-ES on multi-modal func...
This week in AI

Get the week's most popular data science and artificial intelligence research sent straight to your inbox every Saturday.