

INFLUENCE OF THE HEATMASS EXCHANGE AND A GAS BLOWING DIRECTION ON THE STABILITY OF THE SUPERSONIC BOUNDARY LAYER
Gaponov S.A., Terekhova N.M.
Khristianovich Institute Of Theoretical And Applied Mechanics SB RAS, Novosibirsk, Russia
Citation:
Gaponov, S.A. and Terekhova, N.M., (2015) Influence of the heatmass exchange and a gas blowing direction on the stability of the supersonic boundary layer, Modern Science: Researches, Ideas, Results, Technologies, Iss. #1(16), PP. 8  13.

Keywords: layer; stability; laminarturbulent transition; compressible gas; gas blowin 
Abstracts:
Porous cooling is an effective method for the thermal protection of heatstressed elements of technical devices. Blowing direction of a gas relatively of the surface may be different (from normal to tangential).In addition to the thermal protection there is another important problem. It is connected with the control of the laminarturbulent transition. It is known that with an increase of a gas density near the wall the boundary layer stability increases. For increase of the density near a wall it is possible to blow a heavy gas through a porous wall. Unfortunately, the possibility to suppress disturbances in this way is limited. Normal blowing promotes to an appearance of the inflection point in a velocity profile that leads to the destabilization of the flow. For reduction of this effect it is possible to try to blow a gas under a corner to the main flow direction of the. In the present paper gases of different density are modeled by changing of a temperature factor (heating or cooling of a wall). In the paper the joint influence of a mass exchange and a temperature factor is considered. Calculations carried out at Mach numbers M = 2.0, 5.35. It is modelled normal blowing and blowing of other directions, including the tangential one. It is shown that the tangential blowing along the flow leads to the significant stabilization of boundary layers on the relation of both acoustic and vortex mod. At the same time heated gas blowing suppresses acoustic waves and amplifies the vortical perturbations. Blowing of a cold gas affects on the boundary layer stability the reverse way. 
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