{ "id": "1710.04917", "version": "v1", "published": "2017-10-13T13:35:18.000Z", "updated": "2017-10-13T13:35:18.000Z", "title": "Statistics of the relative velocity of particles in turbulent flows : monodisperse particles", "authors": [ "Akshay Bhatnagar", "K. Gustavsson", "Dhrubaditya Mitra" ], "categories": [ "physics.flu-dyn" ], "abstract": "We use direct numerical simulations to calculate the joint probability density function of the relative distance $R$ and relative radial velocity component $V_R$ for a pair of heavy inertial particles suspended in homogeneous and isotropic turbulent flows. At small scales the distribution is scale invariant, with a scaling exponent that is related to the particle-particle correlation dimension in phase space, $D_2$. It was argued [1, 2] that the scale invariant part of the distribution has two asymptotic regimes: (1) $|V_R| \\ll R$ where the distribution depends solely on $R$; and (2) $|V_R| \\gg R$ where the distribution is a function of $|V_R|$ alone. The probability distributions in these two regimes are matched along a straight line $|V_R| = z^\\ast R$. Our simulations confirm that this is indeed correct. We further obtain $D_2$ and $z^\\ast$ as a function of the Stokes number, ${\\rm St}$. The former depends non-monotonically on ${\\rm St}$ with a minimum at about ${\\rm St} \\approx 0.7$ and the latter has only a weak dependence on ${\\rm St}$.", "revisions": [ { "version": "v1", "updated": "2017-10-13T13:35:18.000Z" } ], "analyses": { "keywords": [ "monodisperse particles", "relative velocity", "distribution", "statistics", "joint probability density function" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }