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

Härtel, Carlos; Meiburg, Eckart; Necker, Frieder

J. Fluid Mech. 418, 189-212 (2000).

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

Keywords:

Boussinesq approximations; spectral-element discretizations; compact finite differences; gravity-current head; lobe-and-cleft structure