15H40 : n° 1388 Wave-induced effects on sea spray interactions over waves

Marc Francius Alexander M. J. van Eijk
LSEET
Despite considerable efforts in air-sea interaction studies, an accurate understanding and modeling of the sea spray generation and interactions with the lower atmospheric marine surface layer is still far from being reached. As a matter of fact, the sea spray or the marine aerosols are potentially important to a large number of processes in the marine boundary layer.

16H00 : n° 1403 Towards a General Model for Finely Intricate Moving Random Multi-Phase Systems

Alain Mailliat Alexandre Petroff Fabien Anselmet Roland Borghi
Ecole Centrale Marseille
This presentation addresses multiphase system if their phase domains are distributed in finely intricate moving random patterns. From local discontinuous characteristics, continuous global quantities are defined through both space-time filters and probability averaging. Balance equations for global quantities are derived, new flux terms are indentified and discussed. Overview of aerosol transport through forest canopies is presented as the model application.

16H20 : n° 1200 Turbulent flows interacting with varying density canopies

Laurence Pietri Alexandre Petroff Muriel Amielh Fabien Anselmet
IRPHE
In the case of dense and homogeneous canopies, it is well-known that canopy flows are similar to mixing layer flows (so-called mixing layer analogy). When the canopy becomes sparser, a transition between the mixing layer and the boundary layer perturbed by interactions between element wakes occurs. This transition has still to be fully understood and characterized. An experimental work has been developed in order to study this transition for various density canopies.

16H40 : n° 1354 Turbulence and waves in numerically simulated slope flows

Evgeni Fedorovich Alan Shapiro
School of Meteorology
Direct numerical simulation (DNS) is applied to investigate properties of katabatic and anabatic flows along thermally perturbed (in terms of surface buoyancy flux) sloping surfaces in the absence of rotation. Numerical experiments are conducted for homogeneous surface forcings over infinite planar slopes. The simulated flows are the turbulent analogs of the Prandtl (1942) one-dimensional laminar slope flow. The simulated flows achieve quasi-steady periodic regimes at large times, with turbulent fluctuations being modified by persistent low-frequency oscillatory motions with frequency equal to the product of the ambient buoyancy frequency and the sine of the slope angle. These oscillatory wave-type motions result from interactions between turbulence and ambient stable stratification despite the temporal constancy of the surface buoyant forcing. The structure of the mean-flow fields and turbulence statistics in simulated slope flows is analyzed. An integral dynamic similarity constraint for steady slope/wall flows forced by surface buoyancy flux is proposed and quantitatively verified against the DNS data.