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Torque and Flow Field Optical Measurements of The Single Blade Under Stall Flutter
Procházka, Pavel P. ; Uruba, Václav ; Šnábl, Pavel
The single blade NACA0010 was exposed to the incoming flow inside a channel with rectangular cross-section. The blade was investigated for three different working regimes. The first configuration was for fixed blade. The second regime was for fluttering blade due to flow instabilities and the last one was performed for blade under force excitation. The flow field was measured using Particle Image Velocimetry. A force transducer and a small rotary encoder were used to evaluate the force ratios.
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Dynamics of Machines and Mechanical Systems with Interactions, DYMAMESI 2021
Zolotarev, Igor ; Pešek, Luděk ; Kozień, M. S.
The aim of the DYMAMESI is to facilitate the exchange of up to date information and knowledge among specialists in structural and multibody dynamics, in coupled interacting systems as aero-elasticity, hydro-elasticity, biomechanics, systems with feedbacks and mechatronics. The colloquium DYMAMESI 2021 is cofunded by the Strategy AV21 initiative of the Czech Academy of Sciences of the Czech Republic, and in 2021 will be hosted by Cracow University of Technology, Institute of Applied Mechanics, Section of Dynamics of Systems.
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Numerical simulation of dynamic loading of a test blade in forced torsional vibration
Šidlof, P. ; Vomáčko, V. ; Lepičovský, Jan ; Šimurda, David ; Štěpán, M. ; Luxa, Martin
Within a new project focused on blade flutter research, building on previous experience with the NASA Transonic Flutter Cascade facility, static blade cascade and airfoil flutter experiments realized in cooperation between the Institute of Thermomechanics and Technical University of Liberec, a new test facility is under development for the investigation of high subsonic and transonic flow in a blade cascade under forced torsional oscillation. Apart from aerodynamic loading of the blades, the oscillating blade will be exposed to significant structural stresses due to the highfrequency torsional vibration. In order to avoid structural integrity issues from high-cycle fatigue, a numerical simulation of the stress and displacement of the blade was realized. Regions where equivalent stress reaches maximum values were identified, and elastic deformations were computed. The limits in oscillation amplitude and frequency for the safe operation of the experimental setup were discussed.
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Study of aeroacoustics noise of high-speed aircraft propellers and mitigation of the cause
Prasad, Chandra Shekhar
The project deals with the study of aeroacoustics noise generated by high-speed turboprop propellers and methods to minimize its causes. A reduced order flow solver with aeroacaustic noise capturing characteristics is developed for fast numerical analysis purpose. The acoustical performance will be also studied using flow visualization using article image velocimetry under rotation and acoustics noise will be measured by microphones for both conventional as well as unconventional propeller designs at diferent rotational speeds.
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Measurement of friction coefficient between damping wire and groove
Šnábl, Pavel ; Pešek, Luděk ; Bula, Vítězslav ; Běhálek, V. ; Boháč, T. ; Tašek, H.
Damping wire is being used on railway wheels for noise suppression. It is inserted into a groove of the wheel and dry friction damping reduces vibrations and thus the noise transmitted by the wheel. For increase of durability of the wire, surface treatment of the groove and the ring must be applied to prevent corrosion. Three combinations of diferent surface treatments were studied during reciprocating motion in a set of measurements with diferent frequencies and normal forces to evaluate friction coeficient. Then, those measurements were repeated after a long-time run to evaluate the change of friction coeficient after the wear of the surfaces.
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The new HPC results of 3D FE modelling of dry-friction damping at tie-boss couplings of bladed wheel - 6nd resonant mode
Pešek, Luděk ; Šnábl, Pavel ; Bula, Vítězslav
The paper is a direct continuation of our study published in the last colloquium DYMAMESI. This paper deals with the new results of dry-friction damping calculation of the bladed wheel with tie-boss couplings vibrating at a higher resonant mode, i.e. mode with 6 nodal diameters (ND). The numerical solution of the wheel based on 3D finite element method with surface-to-surface dry friction contact model is applied. Due to dry friction contacts and non-linear solution, it leads to HPC computations and long computation times. Therefore, the earlier proposed computational strategy for damping evaluation where the resonant attenuation is computed directly from the defined resonant initial conditions given by the 6ND mode is used. Comparison of experimental and numerical results of dynamical behaviour of the bladed wheel yields a reasonable agreement for the studied vibration mode.
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Numerical estimation of blade displacement due to air excitation
Mekhalfia, Mohammed Lamine ; Procházka, Pavel ; Tchawou Tchuisseu, Eder Batista ; Hodboď, Robert ; Maturkanič, Dušan
For the last few years, vibration measurement has taken an intense interest from research activities. For this reason, this article considers, besides vibration measurements, the impact of air forced excitation on blade motion, displacement and vibration through both simulation analysis and The Transformation of mathematical analysis that explain the interaction between fluid (Air) and the structure (Blade) into numerical setup along with FEM analysis through ANSYS Software. 3D Blade was created to meet the same characteristics of the real blade to enable real environment criteria for the simulation.
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