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A numerical and experimental study of the Blasius wall jet

O. Levin ; M. Litvinenko ; Valery Chernoray (Institutionen för tillämpad mekanik) ; Lennart Löfdahl (Institutionen för tillämpad mekanik) ; D. Henningson
Abstracts of 56th Ann. Meeting of the Div. of Fluid Dyn. APS, East Rutherford, New Jersey (2003)
[Konferensbidrag, övrigt]

In the current study the wall jet flow of high Reynolds number is investigated. As presented experimental and DNS results demonstrate, for such operating conditions a laminar flow similarity is not reached due to the happening flow breakdown and the three-dimensional effects are important. For the purpose of linear stability investigation, the problem of the flow description is resolved and a boundary-layer solution developing from coupled Blasius boundary layer and Blasius shear layer is implemented, valid in the close downstream field of a slot. Performed linear stability investigations reveal the high instability of two-dimensional eigenmodes and non-modal streaks, and the calculations agree reasonably well with the provided experiments. Furthermore, the nonlinear stage of laminar flow breakdown is studied both with three-dimensional direct numerical simulation and experimentally. A modelling of the "natural" experimental case is achieved using random noise simulations and it is clearly demonstrated that three-dimensional modes are important for the breakdown process. Additionally, a thorough investigation of the nonlinear interactions between the eigenmodes and streaks is made in the DNS and in the experiment with controlled parameters of the forcing.

Denna post skapades 2006-10-11. Senast ändrad 2007-06-28.
CPL Pubid: 22757


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