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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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Numerical simulation and experiments with the profile NACA 0012
Chládek, Štěpán ; Zolotarev, Igor ; Uruba, Václav
This paper introduces the new model of the airfoil and describes both aeroelastic experiments and numerical simulation with the profile NACA 0012. The aeroelastic is the science which studies the flow-structure interaction. The flow field can cause change of the position of the solid body and the body due to the change of its position influences the flow field. Mathematical description of the interaction has to involve both the equations of the fluid dynamic and the equations of motion of the solid body. The first results will be presented from the measuring in the dynamic laboratory and from the measuring in the wind tunnel. The main aim of the experimental part of this research is to cause a self-oscillated motion of the airfoil and to measure the transient flow field during this motion. The numerical part should be identical with the experimental dates.
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The self-excited vibration of the NACA0015 profile
Vlček, Václav ; Zolotarev, Igor ; Kozánek, Jan
The two-dimensional flow patterns around the profile NACA0015 vibrating in self-excitation modes were measured in the wind tunnel by optical methods. The Mach numbers for the self-excited vibrations were in the interval 0.2 – 0.45. Results of the interferometric measurement and the profile kinematic movements during the self-oscillations are presented.
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Interakce a zpětné vazby 2011
Zolotarev, Igor
Proceedings INTERACTION AND FEEDBACKS 2011 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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Forces actingon the fluttering. Profile in the wind tunnel
Vlček, Václav ; Kozánek, Jan ; Zolotarev, Igor
2D experiments with profile NACA0015 supported with two degrees of freedom in aerodynamic tunnel of suction type were realized. One degree of freedom was rotation around the profile axis in 1/3 chord distance behind the profile leading edge, the second one was the vertical translation. The interferometric visualization of the flow field in the vicinity of the profile during its self-excited vibration was realized. Forces acting on the profile and the pressure distribution on the profile surface resulting from the interferometric measurements are presented.
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