2023/10/28 by Sudheer, M. V. R., Varma, Sarath Chandra, Kumar, Aloke +1
#FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Soft Condensed Matter (cond-mat.soft)
paper · doi:10.48550/arxiv.2310.18707
Recent investigations into coalescence dynamics of complex fluid droplets revealed the existence of sub-Newtonian behaviour for polymeric fluids (elastic and shear thinning). We hypothesize that such delayed coalescence or sub-Newtonian coalescence dynamics may be extended to the general class of shear thickening fluids. To investigate this droplets of aqueous corn-starch suspensions were chosen and its coalescence in sessile pendant configuration was probed by high-speed real time imaging. Temporal evolution of the neck (growth) during coalescence was quantified as a function of suspended particle weight fraction ϕw. The necking behaviour was found to evolve as the power-law relation R=atb where R is neck radius with exponent \b≤0.5 implying it is a subset of the generic sub-Newtonian coalescence. Second significant delay in the coalescence dynamics is observed for particle fractions beyond the jamming fraction ϕw> ϕJ≥0.35. Our proposed theoretical model captures this delay implicitly through altered suspension viscosity stemming from increased particle content.