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Dynamika odtržení řízené mezní vrstvy na válci
Uruba, Václav ; Matějka, Milan ; Procházka, Pavel
Dynamical aspects of the boundary layer separation on a circular cylinder in cross-flow are studied experimentally. Two cases are compared, the base case and the case with excitation using a synthetic jet actuator. The TR-PIV technique was used to catch both space and time velocity field correlations. Instantaneous velocity fields and skin friction distributions are evaluated. For dynamical structures study, the BOD method was applied based on energetic principle. Dynamical modes connected with vortex shedding process, dynamical excitation by synthetic jet and transition to turbulence are identified.
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Pasivní a aktivní metody řízení mezní vrstvy
Matějka, Milan ; Popelka, Lukáš
The paper deals with influence of the passive and active method of control on the flow field. It is well known fact that boundary layer separation has a fundamental effect on aircraft airfoil performance, compressors and turbines performance and other bodies, subject to study of internal and external aerodynamics. By the boundary layer control, it is possible to obtain both operational economy and extension of efficient operational region. Traditional methods of active boundary layer control are very complex and their application needs complex facilities. Modern methods based on the control by synthetic jets or plasma actuator are simpler, but their design has to be carried out at rather well experience and detailed knowledge about boundary layer and its interaction with the actuator.
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