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**Analysis and direct numerical simulation of the flow at a gravity-current head. I: Flow topology and front speed for slip and no-slip boundaries.**
*(English)*
Zbl 0985.76042

From the summary: We perform direct numerical simulations of gravity-current fronts in the lock-exchange configuration. The case of small density differences is considered, where the Boussinesq approximations can be adopted. The key objective of the investigation is a detailed analysis of the flow structure at the foremost part of the front, where no previous high-resolution data were available. For the simulations, high-order numerical methods are used, based on spectral and spectral-element discretizations and compact finite differences. A three-dimensional simulation is conducted of a front spreading along a no-slip boundary at a Reynolds number of about 750. The simulation exhibits all features typically observed in experimental flows near the gravity-current head, including the lobe-and-cleft structure at the leading edge.

### MSC:

76F65 | Direct numerical and large eddy simulation of turbulence |

76F25 | Turbulent transport, mixing |

76M22 | Spectral methods applied to problems in fluid mechanics |

76M20 | Finite difference methods applied to problems in fluid mechanics |