Used in Acoustic Projects Calculation of Reflection Coefficient for End Opening of Channel without Flange

The computational error analysis for coefficient of reflection of plane sound waves at the end of opening channel without flange performed by means of formulas commonly used in practice has demonstrated their unacceptability for accurate acoustic calculations, and limitations of the Helmholtz numbers’ range, where these formulas are applicable. In this work have been proposed calculated dependences, convenient for practical usage and enabling more accurately calculate by computer approach the considered quantity’s values in a whole range of existence of the plane waves in the channel.

Using an Evaporating Meniscus to Trap Cells in a Microfluidic Chip: Design and Modeling

A microfluidic device based on Marangoni effect on a volatile meniscus is proposed for cell enrichment and collection. The device consists of a main channel in which cells are flowing with the mainstream, and an open-outlet channel which is connected with the main channel. A meniscus is sustained in the opening channel and keeps evaporating since the outlet is open to the atmosphere. Marangoni vortexes are generated near the meniscus due to the non-uniform evaporation on the meniscus. The vortexes influence the flow field and cell dynamics in the main channel, which can be used to trap the cells. A comprehensive numerical simulation is adopted in present work to reveal how the heat and mass transport going on in such a system. The evaporation and vapor diffusion at the liquid-air interface, and the vapor diffusion in air are considered. The convections due to the evaporation and Marangoni effect are simulated.