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Dynamic and heat transfer analysis of a container with measuring instruments for space probes
Zolotarev, Igor ; Bula, Vítězslav ; Šnábl, Pavel ; Gabriel, Dušan ; Dobiáš, Jiří ; Masák, Jan ; Snížek, Jan ; Souček, Jan
Rocket boosters and spacecraft are subject to intense acoustic environments during launch, which induce high levels of vibration in structural elements and equipment. In addition, elastic structural interactions with propulsion systems and flight control systems can produce low-frequency, high-deflection flight instabilities. Natural vibration of the container with measuring equipment were studied by numerical and experimental methods in the laboratory of Institute termomechanics CAS. Heat transfer analysis inside the container was made by FEM with respect to the conditions during start of the rocket and work in space.\n
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Engineering Mechanics 2019
Zolotarev, Igor ; Radolf, Vojtěch
The proceedings contains papers presented at the 25th International Conference on Engineering Mechanics, which has been held in Svratka resort in Czech Republic under auspices of the Czech Society of Mechanics and being a part of IFTOMM (The International Federation for the Promotion of Mechanism and Machine Science) activities. As it corresponds with character of the conference, this proceedings consists of several topic oriented parts: Biomechanics, Fluid mechanics, Dynamics, Fracture mechanics, Kinematics, Mechatronics, Reliability of structures, Mechanics of solids, Technological processes, Thermodynamics. The volume represents a well-balanced overview of theoretical, numerical and experimental work on fundamental and applied studies.
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Dynamics of Machines and Mechanical Systems with Interactions : DYMAMESI 2018
Zolotarev, Igor ; Pešek, Luděk ; Kozieň, M.
The Colloquium Dymamesi is continuing near the 20 years history of two conferences Dynamics of Machines and Interaction and Feedbacks. From 2017 the Colloquium is organized within the Czech-Polish (IT ASCR Prague & CUT Crakow) collaboration and the first one was held in CUT in Cracow. The prezentations were divided into the three sections: dynamics of machines, interactions and energetics. The Colloquium DYMAMESI 2018 was for the first time supported also by Programme Strategy 21 (AV21).\n
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Self-excited oscillation properties of the profile NACA0015 in subsonic flow
Zolotarev, Igor ; Vlček, Václav ; Kozánek, Jan
Self-excited oscillations of the profile NACA0015 in subsonic flow were realized in the wind tunnel. The plunge support had the same elasticity for all experiments, the pitch support had seven different elasticity parameters. During our experiments different types of selfexcited vibration (flutter, stall flutter) were observed. Range of Mach numbers was M = 0.08–0.45, corresponding range of Reynolds numbers is Re = (1–5)·105, when the chord length is used as the characteristic dimension of the profile.\n
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DYMAMESI 2017
Kozieň, M. ; Pešek, Luděk ; Zolotarev, Igor
The Colloquium Dymamesi is continuing near the 20 years history of two conferences Dynamics of Machines and Interaction and Feedbacks. From 2017 the Colloquium is organized within the Czech-Polish (IT ASCR Prague & CUT Crakow) collaboration and the first one was held in CUT in Cracow. The prezentations were divided into the three sections: dynamics of machines, interactions and energetics. The Colloquium DYMAMESI 2017 was for the first time supported also by Programme Strategy 21 (AV21).
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Some experimentally determined properties of a profile in case of self-excited oscillations in subsonic flow
Vlček, Václav ; Zolotarev, Igor ; Kozánek, Jan ; Šidlof, Petr ; Štěpán, M.
In the wind tunnel of the Institute of Thermomechanics of the AS CR,v .v. i., experiments were realized with the profile NACA0015 in the presence of the self-excited oscillation. The oscillation of the profile with pitch and plunge degrees of freedom was excited by the subsonic air flow. The plunge support had the same elasticity for all experiments, the pitch support had seven different values of elasticity. Within experiments different types of self-excited vibration (flutter, stall flutter, deep stall flutter) were realized. Range of Mach numbers were M=0.08–0.45, when the chord length is used as the characteristic dimension of the profile. The frequency and amplitude characteristics of the oscillating profile were experimentally determined.\n
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The effect of the pitch support elasticity on the NACA0015 profile aeroelastic properties
Vlček, Václav ; Zolotarev, Igor ; Kozánek, Jan
The aeroelastic experiments realized in wind tunnel of the Institute of Thermomechanics with Mach numbers M ~ 0.20-0.22 and with the interval of Reynolds numbers Re = (2.4-2.6).105, are presented. These results correspond to the self-excited vibration of the profile NACA0015 with two degrees of freedom allowing the profile rotation in 1/3-chord axis and allowing the vertical displacement of the profile. The dependence of vibration frequency on the wind-flow velocity has been obtained. Comparing with the previous experiments the influence of the pitch support elasticity on the profile aeroelastic properties was determined.
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Computation of aerodynamic damping in aeroelastic system based on analytical and numerical approach
Chládek, Štěpán ; Horáček, Jaromír ; Zolotarev, Igor
The paper describes computation of aerodynamic damping and natural frequencies of aeroelastic systems. The damping is a critical parameter for the stability analysis of aeroelastic systems. Structural damping of the system is important for very low fluid flow velocities, however by increasing the flow velocity, the aerodynamic damping dominates in the instability search. The damping can be evaluated in time or in frequency domain. The presented computation of aerodynamic damping consists of two analytical and one numerical approach. The analytical approaches are represented by the well-known pk method and the unsteady panel method. The pk method is based on Theodorsen unsteady aerodynamics and on the computation of complex eigenvalues of the system as functions of the flow velocity. The unsteady panel method enables the computation of the interaction between aeroelastic system and fluid flow. The aerodynamic damping is evaluated in time domain from the system response to given initial conditions. The numerical approach is based on the finite volume method (FVM) modelling the complete fluid-structure interaction (FSI) coupled problem. The aerodynamic damping is also computed from the system response to a given initial condition. The results of the mentioned methods are compared for the profile NACA 0012 with two degrees of freedom (2-DOF) for plunge and pitch motion around an elastic axis.
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