Molecular dynamics study of flow past an obstacle in strongly coupled Yukawa liquids

Turbulence is one of the outstanding open problems. Fluid flow past an obstacle is simplest of all paradigms to understand the transition to turbulence. For Navier-Stokes liquids, a transition to turbulence is fully governed by Reynolds number (Re). Using classical molecular dynamics simulation of particles interacting via a Yukawa-type interaction, it is demonstrated unequivocally that for a given Re, the transition from laminar to turbulent flow is controlled by strength and range of inter-particle potential. For a wide range of inter-particle interaction strengths and ranges, our simulation data are seen to collapse onto a universal Strouhal-Reynolds curve with new asymptotic values for a range of Re, 2 ≤ Re ≤ 35. From the emergence of vortex street structures behind the obstacle, it is evident that the onset of turbulence is possible at low Re in Yukawa liquids. Growth rates of the instability are obtained using atomistic calculations and are observed to increase quadratically with low values of Re.