Our analysis was focused on two main aspects:

1. Simulation of the fluid flow characteristics as well as quantification of the arising shear forces at the plate/plate flow chamber with reliable reproducibility
2. Assessment of the impact of fluid shear stress on osteoblast cells in terms of altered cell morphology and intracellular structural changes

Evaluation of the fluid flow characteristics by computerised simulations and quantification of the resulting forces

The computational fluid dynamic analysis and the quantification of the occurring shear forces within the plate/plate flow chamber were central part of this investigation. The cellular-fluid flow setup was based on the fact that osteoblast cells show responses at 10 dyn/cm² at a speed level of 200 rpm.

On the topside of the upper plate (rotating glass panel), the computerised simulations demonstrated a gradient increased flow with shear forces from the centre (1 dyn/cm²) to the periphery (10 dyn/cm²). Minor effects of shear forces (0–2 dyn/cm²) were recorded on the surface of the bottom plate. It could be demonstrated that a bigger radius of rotation correlates with higher shear forces as expressed in formula 1. Further simulations aimed to verify the pattern of fluid flow (laminar versus turbulent flow). For this purpose, the conditions on the upper and lower surface of the upper plate as well as in the area in between the two plates were of particular interest. The simulations revealed a strong turbulent flow on the entire top surface of the upper plate, especially in the centre and the area around the circumferential edges (Fig. 2). The flow from the peripheral region turned backward and amplified the turbulent flow on the top surface. The development of two opposite flow directions was observed within the area in between the plates. The flow along the lower plates’ surface was directed from the periphery to the centre whereas the fluid movement along the underside of the upper plate was inversely orientated (Fig. 2).