Full-field flow measurement in evaporating sessile droplets based on the Scheimpflug principle

The direct visualization of flow fields plays an important role in droplet evaporation. However, the refraction of light at the curved droplet surface makes it challenging to obtain the accurate flow field. To solve this problem in evaporating sessile droplets, a full-field flow visualization measurement employing the Scheimpflug principle is proposed and a mapping method to eliminate the perspective effects on the particle image velocimetry results is introduced. Compared with the distorted images captured from the side of the droplet, the proposed method can improve the measurement accuracy significantly and the flow details near the droplet surface can be obtained.The direct visualization of flow fields plays an important role in droplet evaporation. However, the refraction of light at the curved droplet surface makes it challenging to obtain the accurate flow field. To solve this problem in evaporating sessile droplets, a full-field flow visualization measurement employing the Scheimpflug principle is proposed and a mapping method to eliminate the perspective effects on the particle image velocimetry results is introduced. Compared with the distorted images captured from the side of the droplet, the proposed method can improve the measurement accuracy significantly and the flow details near the droplet surface can be obtained.