National Repository of Grey Literature 23 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Project: Transition to turbulence modeling
Horák, V. ; Hoření, Bohumír
The project is focused on the transition from laminar to turbulent flow modelling. Developed code will be formulated in such a way to enable an effective parallel processing.
Numerické simulace a experimentální měření pulzačního proudění
Chára, Zdeněk ; Hoření, Bohumír
The contribution presents numerical as well as experimental investigations of laminar and turbulent pulsating flow in an initial part of a rigid pipe. The simulations were performed with help of Fluent 6.3. Measurements of velocity profiles were done by an ultrasound velocity monitor UVP.
A possibility of ultrasonic method to measure flow characteristics
Chára, Zdeněk ; Matoušek, Václav
Results of velocity-field measurements by the ADV (Acoustic Doppler Velocimetry) probe are presented for various geometrical arrangements (open channel flow, flow behind a rectangular cylinder, flow through a hole in a plate). The measurements are compared with those carried out simultaneously using the LDA method.
Shear-driven cavity flow at high Reynolds numbers
Chára, Zdeněk ; Kysela, Bohuš ; Hoření, Bohumír
The paper deals with a research of a shear-driven cavity flow at high Reynolds numbers (Re= 12000-100000). PIV method was used with a continuous light source and at selected profiles LDA method was used, too. Numerical k-omega, SST model was used for the same range of the Reynolds numbers.
Time-resolved PIV and LDA measurements of pulsating flow
Matěcha, J. ; Novotný, J. ; Adamec, J. ; Kysela, Bohuš ; Chára, Zdeněk
The paper deals with an experimental investigation of pulsating flow in a circular tube. Two experimental techniques were used – Time resolved PIV and LDA and the results were compared.
Strategie řízení odtržení mezní vrstvy
Uruba, Václav ; Knob, Martin ; Popelka, Lukáš
Experimental results of a boundary layer separation control in adverse pressure gradient are given. Three strategies are chosen: passive (wall roughness, vortex generator) and active (synthetic jet). The Time-resolved PIV method was used. Special attention was paid to dynamical effects.
Dynamika odtržení mezní vrstvy
Uruba, Václav ; Knob, Martin ; Popelka, Lukáš
Dynamics of separation process of a turbulent boundary layer subjected to adverse pressure gradient is studied experimetally. The Time Resolved PIV method is used to acquire spatiotemporal data. The flow-field in the vicinity of the separation zone is found to be extremely complex.
Application of TR-PIV Method to Turbulent Flow-Field Studies
Uruba, Václav ; Knob, Martin
The paper deals with conditions of correct application of the Time Resolved – Particle Image Velocimetry (TR-PIV) method to study a turbulent flow-field. The method is able to catch both spatial and temporal correlation of the velocity field simultaneously, However the method resolution is limited. Influence of those limitations on evaluated results is shown. The TR-PIV hardware fy DANTEC is taken into account.
Stručný přehled vírových identifikačních metod s aplikací na 2D PIV data
Knob, Martin ; Uruba, Václav
A brief survey of four basic vortex identification methods, namely the Q-criterion,the λ2 method, the Γ2 method and the Complex eigenvalue method, is given in this contribution. All the methods are investigated on an artificial flow- field as well as an unsteady signal, obtained by the TR PIV system. The results of all the methods are evaluated and compared.
O stopě turbulence a tišině
Jonáš, Pavel
The purpose of the contribution is to collect information on the generation, propagation and coalescence of turbulent spots and calmed regions in a transitional boundary layer. The appreciation of the behaviour of both turbulent spot and calmed region under turbulent free stream is the focus of this study.

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