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.