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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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Optická měření proudového pole při obtékání samobuzeně kmitajícího profilu
Vlček, Václav ; Kozánek, Jan ; Zolotarev, Igor
V příspěvku jde o interferometrické vyhodnocení aerodynamického měření proudu vzduchu v okolí profilu NACA0015 v režimu samobuzeného kmitání, realizované v aerodynamickém tunelu Ústavu termomechaniky. Zkušební profil vykonával pohyb odpovídající dynamické soustavě o dvou stupních volnosti ve vertikalním směru a rotoval kolem osy umístěné v 1/3 profilu. Odpovídající Machovo číslo bylo 0.45. Je prezentována kinematika profilu, působící síly a momenty během samobuzeného kmitání.
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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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Použití interferometrických měření pro výpočet sil a momentů působících na samobuzeně kmitající profil
Vlček, Václav ; Kozánek, Jan ; Zolotarev, Igor
Na měřící trati podtlakového aerodynamického tunelu Ústavu termomechaniky AV ČR v.v.i. byla uskutečněna interferometrická měření proudového pole při obtékání samobuzeně kmitajícího profilu NACA0015 uloženého jako dynamický systém se dvěma stupni volnosti. Ty umožňují posuv profilu napříč proudem vzduchu a rotaci kolem osy umístěné v 1/3 tětivy profilu za náběžnou hranou. Jsou uvedeny výsledky měření získané při rychlosti proudu M = 0.28 a Reynoldsově čísle 0.34.106. Použitá metodika vyhodnocování nestacionárního obtékání z optických měření je ve stadiu vývoje, proto je třeba považovat uvedené výsledky za předběžné.
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