Yinxiang Ma

When a shock wave crosses a density interface, the Richtmyer–Meshkov instability causes perturbations to grow. Richtmyer–Meshkov instabilities arise from the deposition of vorticity from the misaligned density and pressure gradients at the shock front. In many engineering applications, microscopic surface roughness will grow into multi-mode perturbations, inducing mixing between the fluid on either side of an initial interface.

Oil-in-water (O/W) emulsions are widely used in industrial production, food science, petrochemicals, and other fields. Quantitative measurement of the interaction between droplets is essential for the in-depth understanding of the stability mechanism of O/W emulsions. Optical tweezers are able to accurately and quantitatively measure the interaction forces between droplets in oil-in-water emulsion systems at the microscopic scale and offer numerous advantages.

Acceleration of objects in fluids widely exists in biological propulsions and contains rich unsteady fluid mechanisms. In this paper, the instantaneous drag force on accelerating normal flat plates (circular, elliptical, square, and rectangular plates) in a wide range of dimensionless acceleration (⁠ ⁠) is measured, and the underlying mechanism for force generation is investigated.