Interaction between gas flow and a Lamb waves based microsensor

The interaction between the gas flow and Lamb waves is investigated in this paper. Depending on the fact that the phase velocity is higher or lower than the gas sound velocity, we will get evanescent waves (EW) or leaky Lamb waves (LLW) in the gas along the solid–gas interface. In the LLW case, experiments showed that gas flow had not evident effects on Lamb waves’ propagations. In the EW case, the interaction between the gas flow and the Lamb waves was observed clearly when the Lamb wave phase velocity is close to the gas sound velocity. This interaction is related with the gas flow velocity profile within the boundary layer. The experimental results show that this sensor is very promising for many experiments involving gas flows such in wind tunnels, micro channels characterization, and can lead to multi-parameters measurements.