National Repository of Grey Literature 12 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Aeroacoustic Noise Source Investigation in the Case of the Blade Cascade
Procházka, Pavel P. ; Antoš, Pavel ; Šnábl, Pavel
The blade cascade consisted of five NACA 0010 profiles is examined in the framework of project dealing with nonlinear dynamic phenomenon related to stall flutter of flexible profiles with pitch degree of freedom in subsonic flow. Various angles of attack (AoA) of the cascade generates different (broadband) aeroacoustic noise. The goal of this article is to describe the existence of possible noise sources using two experimental methods – Particle Image velocimetry (PIV) and hot-wire (HW) anemometry.
Experimental and numerical evaluation of blade cascade instability using travelling wave mode approach
Chindada, Sony ; Šnábl, Pavel ; Pešek, Luděk
The stability of experimental blade cascade with five NACA 0010 profiles was measured and evaluated with travelling wave mode approach with three inner blades oscilating. The measured moment of the middle blade consist of not only the aerodynamic moment from the flow but also structural moment from the blade dynamics. Two days of obtaining the aerodynamic moment from the measured data are herein presented and the results compared. In addition, numercial simulations were done and the results from 2D CFD analysis in ANSYS are compared with the experimental data.
Turbine blade linkages in reduced modal synthesis model
Pešek, Luděk ; Šnábl, Pavel
The paper is the first stage of our modelling turbine blade linkages in reduced modal synthesis model. The modal synthesis method is used for the dynamic behaviour studies of turbine bladed wheels with frictional inter-blade linkages and in case of the microslips the stiffening effect of the linkages play an important role in wheel dynamics. The paper presents the first results of modal analysis of the wheel when springs were used to substitute the linkages in the modal synthesis model.
Identification of material constants of rubber damping segments by modal analysis for railway rubber-resilient wheels
Šulc, Petr ; Šnábl, Pavel ; Pešek, Luděk ; Bula, Vítězslav
In this paper, an experimental and numerical modal analysis is described to assess two rubber compounds for the damping segments of a railway wheel. The subject of this comparison is materiál parameters such as Young’s modulus and loss factor for both compounds in the frequency range up to 6.5 kHz. From this comparison, an idea of the damping, stiffness and durability of these rubber segment materials inside these wheels is obtained.
Measurement and analysis of vibration and acoustic emissions of a railway wheel under defined dynamic excitations
Pešek, Luděk ; Prasad, Chandra Shekhar ; Šnábl, Pavel
The paper deals with experimental vibro-acoustics of railway wheel. The methodology for evaluation of effect of vibrational plate dampers was elaborated. The four variants of the wheel was measured and analyse to achieve the optimal solution of the dampers.
Approaches to dynamical analysis of rotors with parameters of uncertain magnitudes
Zapoměl, Jaroslav ; Kozánek, Jan ; Košina, Jan ; Cibulka, Jan
In many cases, the rotor configuration or loading characteristics are described by parameters of uncertain magnitude. Several procedures were developed to analyse such systems. This paper deals with the approach based on application of the fuzzy numbers. The investigated mechanical system is a rotor supported by hydrodynamic bearings. The parameters of its loading have uncertain values.
Identification of the blade tip possition and measurement techniques using the BTT method
Maturkanič, Dušan ; Procházka, Pavel ; Hodboď, Robert ; Mekhalfia, Mohammed Lamine
This paper describes the existing practice in identifying and defining the position of the blade tips and the relevant technique for measuring their vibration during rotation. In connection with the effort to precisely define the position of the vibrating blade, the paper also analysed the possibilities of unambiguous determination of its position. This work creates a parallel branch to signal processing in the complex system of precision measurement and analysis of blade vibration, which was mentioned in previous papers.
The International Colloquium Dynamics of Machines and Mechanical Systems with Interactions, DYMAMESI 2022
Zolotarev, Igor ; Pešek, Luděk ; Kozień, M. S.
The papers of the DYMAMESI are divided into the three sections and focused on the Dynamics of Machines, Interactions and Power Engineering.
Experimental investigation of the frequency-modal properties of the measuring container for LUNA mission
Zolotarev, Igor ; Bula, Vítězslav ; Šnábl, Pavel ; Snížek, Jan ; Souček, Jan
This paper continues investigations of the measuring equipment for space missions. The frequency-modal properties of the measuring container for LUNA mission were obtained by experimental investigation.
Vibration mode shape extraction of bladed disk
Mekhalfia, Mohammed Lamine ; Procházka, Pavel ; Tchawou Tchuisseu, Eder Batista ; Maturkanič, Dušan ; Hodboď, Robert
This research paper deals with the experimental protocol followed to visualize the vibration mode shape of an aero-engine bladed disk. This study is based on a comparison between the numerical results obtained through Finite element methods (FEM) using ANSYS software and experimentally using the laser Doppler vibrometer. Therefore the bladed disk was transformed into a 3D virtual environment and structural analysis was performed. The results demonstrate a match between the numerical and the experimental one, this match offers the possibility for using the model for future studies.

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