## Abstract

Accurate prediction of unsteady motion of a particle and forces acting on it is important in particle-laden two-phase flows. The theory is well developed in the limits of potential flow and low Reynolds number flow. However, the case of finite particle Reynolds number is not well understood. In many cases, low Reynolds number results are extended to finite Re with modifications in the added mass and history forces. Such modifications are however based on the assumption that the ambient flow is uniform. Effect of flow gradient on the motion of a particle at finite Re has been rarely addressed. Here we develop a high resolution numerical scheme using spectral methods to study the effect of spatial non-uniformity. Numerical simulations are performed for two cases: a) a stationary particle subjected to an externally imposed planar strain flow for 10 ≤ Re ≤ 300 and b) unsteady motion of a particle moving in a linear shear flow at initial Re = 200. For the former case, effect of strain is to significantly increase drag and change the wake. It is shown that the added mass effect in finite Re case is not always well predicted by the potential flow result. Unsteady motion of a particle obtained from present simulation also appears to be different from that predicted by the standard drag law or the BBO-type equation.

Original language | American English |
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Pages (from-to) | 743-750 |

Number of pages | 8 |

Journal | American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED |

Volume | 253 |

State | Published - 2000 |

Externally published | Yes |

## ASJC Scopus subject areas

- General Engineering