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Flutter at a low velocity
Vlček, Václav ; Kozánek, Jan ; Zolotarev, Igor
Aeroelastic experiments with the profile NACA0015 were realized in the suction type aerodynamic tunnel of the Institute of Thermomechanics, Czech Academy of Sciences, Prague. The profile had two degrees of freedom realized in translation and rotation motion and flow velocity was just up its critical value. The flow field was measured with interferometry method and the results obtained at the velocity M = 0.23 in the flutter regime are presented. The evaluation of interferogramms enabled to determine the components of the drag and lift forces.
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Engineering Mechanics 2013
Zolotarev, Igor
The objective of the 19th conference is to provide a forum for researchers to discuss the state-of-the-art in Mechanics of Solids, Fluids and Thermomechanics, this particularly in connection with problems under investigation in the Czech Republic. Problems of Engineering Mechanics related to the contemplated topics can be discussed, and their solutions presented, during the sessions of the Conference, held at the Hotel of the ŽĎAS, a.s., situated in the beautiful countryside of the Žďár Highlands.
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Engineering Mechanics 2013 - book of extented abstracts
Zolotarev, Igor
The objective of the 19th conference is to provide a forum for researchers to discuss the state-of-the-art in Mechanics of Solids, Fluids and Thermomechanics, this particularly in connection with problems under investigation in the Czech Republic. Problems of Engineering Mechanics related to the contemplated topics can be discussed, and their solutions presented, during the sessions of the Conference, held at the Hotel of the ŽĎAS, a.s., situated in the beautiful countryside of the Žďár Highlands.
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Unsteady aerodynamic forces measured on a fluttering profil
Vlček, Václav ; Zolotarev, Igor ; Kozánek, Jan
The evaluations of optical measurements of the flow field near the fluttering profile NACA0015 with two-degrees of freedom are presented. Mach number of the airflow was M = 0.21 and M = 0.45, the boundaries of the flutter occurrence. Aerodynamic forces acting on the profile were evaluated in the drag and lift components which enabled to obtain independently the forces corresponding to the upper and lower surfaces of the profile. Using the mentioned decomposition, the new information about mechanism of flutter properties was obtained. The force effects on the upper and lower surfaces are in opposite phases and they are partially eliminated as a result of the circulation around the profile. The cycle changes of this forces cause the permanent energy contribution from the airflow to the vibrating system.
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Aeroelastic experiments with the structural properties variation
Chládek, Štěpán ; Zolotarev, Igor ; Uruba, Václav
The paper measurements on a model of the airfoil NACA0012. Usually there is a limit range of the flow velocity in the wind tunnel. The chosen wind tunnel is usually fixed, the only one possibility is to modify the structural properties of the experimental stand. There are presented two kinds of modifications, one is based on the geometry variation, the other one on the added mass approach. Both of them have been verified experimentally.
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Interaction and Feedbacks 2012
Zolotarev, Igor
Proceedings INTERACTION AND FEEDBACKS 2012 deals with the problems of interactions of dynamic systems with surrounding liquid or fluent environment and the solutions of the dynamic systems with feedbacks.
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The calculation of the forces and moments acting on the fluttering profile using interferometric measurements
Vlček, Václav ; Kozánek, Jan ; Zolotarev, Igor
Experimental investigation of the profile NACA0015 fixed as a dynamic system with two degree of freedom vibrating in self-excitation modes were measured in the wind tunnel of the Institute of Thermomechanics AS CR by interoferometric methods. The profile moved in the vertical direction and rotated around the elastic axis in 1/3 of the profile chord. Presented results of the aeroelastic measurement correspond to the flow velocity M = 0.28 and Reynolds number 0.34·106. Time depends of the airflow forces and moments acting on the vibrating profile were obtained newly in this contribution. Applied method of the evaluation is now in the process of its evolvement, therefore presented results should be regards as preliminary conclusions.
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