3.3 Comparison of experimental and simulated deformation forP. aeruginosa biofilm
In order to further validate the computational model, an experiment similar to the above was carried out for the P. aeruginosabiofilm. In this case, the Reynolds number was Re=48. The biofilm depth was greater than the depth of field of OCT, so only upper part was imaged.
The experimental and model-predicted deformations over time was compared for three locations on the boundary of the P. aeruginosa biofilm (Fig. 9). The relative average error between model-predicated displacement and experimentally measured displacement for the three points was 22.2%. The averaged error was 2.28 µm for the tracked point on line 1, 3.05 µm for line 2, and 1.73 µm for line 3. The relative averaged error was larger (22%) compared to the alginate biofilm data (13%). This is expected, because the P. aeruginosa biofilm geometry was more complex than that of the alginate biofilm.
The steady-state displacement was in good agreement with the experiment, with consistent values among all the tracking positions. On the other hand, the simulated deformation took longer time to reach a plateau compared to the experimental data. This difference may due to the simplified geometry used in the model. The more dendritic and porous morphology of the real biofilm may introduce more water content, affecting the biofilm mechanical properties and physical behavior. Also, the simplification from irregular 3D structure to the 2D morphology could also lead to deviations. In all, it was concluded that the computational model is consistent with the experimental deformation.