As a result, any added electron dragging effect due to the increase in transverse flow was buried in the effect of the overall flow momentum decrease due to the decrease in x-directional flow velocity in Figure 3b. Moreover, the increased vorticity seems to interfere with the out-of-plane phonon mode, minimizing the momentum transfer from the fluid flow in Figure 3c. In summary, the significant decrease in the induced voltage in the presence of herringbone grooves is because of the overall flow momentum decrease due to the decrease in x-directional flow and increased vorticity.
Figure 4 shows the flow-induced voltage generation with time at a fixed flow rate (1,000 μL/min) for all four configurations. It is notable that the signals for the perpendicular alignment (in Figure 4b,d) have
more noise/oscillation than those for the parallel alignment (in Figure 4a,c). This difference seemed to arise from the distinct Ulixertinib supplier voltage generation mechanisms. Sirolimus As the out-of-plane phonon mode is produced by momentum transfer from the flowing fluid to the graphene layer, the induced voltage tends to show greater oscillation than the signal obtained in phonon dragging mode. This signal oscillation is amplified with the herringbone grooves due to the increased vorticity in the fluid flow in Figure 4d. These data also support our previously proposed different mechanisms for flow-induced PRKACG voltage generation according to the electrode-flow alignment. Figure 4 Flow-induced voltage with time. (a) Parallel alignment without herringbone grooves. (b) Perpendicular alignment without herringbone grooves. (c) Parallel alignment with herringbone grooves. (d) Perpendicular alignment with herringbone grooves. Conclusions In conclusion, we investigated flow-induced voltage generation over a graphene monolayer in the presence of staggered herringbone grooves to better understand the origin of the voltage generated. The flow-induced voltage decreased
significantly in the presence of herringbone grooves in both parallel and perpendicular alignments. The numerical simulation study revealed that the presence of herringbone grooves decreased longitudinal flow velocity while increasing transverse flow and vorticity. As a result, the directional charge dragging effect was significantly reduced in the parallel alignment, resulting in decreased voltage generation. In the case of the perpendicular alignment, the momentum transfer from the fluid flow to the graphene (out-of-plane phonon mode) was affected by the decreased flow velocity and increased vorticity, causing the voltage generation to drop. We also found that the voltage signal with the perpendicular alignment showed a bigger oscillation than that of the parallel type and that the signal oscillation was amplified by the herringbone groove.