Unraveling Stress Relaxation of Cornstarch Droplet Impacting on Deep Pool

We recently studied the impact dynamics of droplets containing cornstarch particles on a deep water pool with varying Weber number and volume fractions of particles. We have found distinctive impact phenomena compared to Newtonian droplet impact, such as solid-like impact behavior. To better understand the origin of these phenomena, we performed rheology measurement to assess the stress relaxation of the cornstarch suspension. Specifically, different relaxation mechanisms have been observed with various volume fraction of particles and imposed shear rate, which could explain why liquid and solid phases of the droplet during impact process occurred. In addition, the relaxation timescale can be used to compare with the inertial time scale of the impact to further unravel the controlling physics of the distinctive impact phenomena observed in cornstarch droplet impact.