National Repository of Grey Literature 33 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
Visualization of Flow Separation and Control by Vortex Generators on an Single Flap in Landing Configuration
Součková, Natálie ; Kuklová, J. ; Popelka, Lukáš ; Matějka, Milan
This paper focuses on a suppression of the flow separation, which occurs on a deflected flap, by means of vortex generators (VG's). An airfoil NACA 63A421 with a simple flap and vane-type vortex generators were used. The investigation was carried out by using experimental and numerical methods. The data from the numerical simulation of the flapped airfoil without VG's control were used for the vortex generator design. Two sizes, two different shapes and various spacing of the vortex generators were tested. The flow past the airfoil was visualized through three methods, namely tuft filaments technique, oil and thermo camera visualization. The experiments were performed in closed circuit wind tunnels with closed and open test sections. The lift curves for both cases without and with vortex generators were acquired for a lift coefficient improvement determination. The improvement was achieved for several cases by means all of the applied methods.
Infrared Thermography as a Visualization Tool of Flow Control by Vortex Generators
Součková, Natálie ; Kuklová, J. ; Popelka, Lukáš ; Matějka, M.
This paper focuses on a suppression of the flow separation, which occurs on a deflected flap, by means of vortex generators (VG's). An airfoil NACA 63A421 with a simple flap and vane-type vortex generators were used. The investigation was carried out by using experimental and numerical methods. The data from the numerical simulation of the flapped airfoil without VG's control were used for the vortex generator design. Two sizes, two different shapes and various spacing of the vortex generators were tested. The flow past the airfoil was visualized through two methods, namely oil and infrared thermography visualization. The lift curves for both cases without and with vortex generators were acquired for a lift coefficient improvement determination. . The experiments were performed in closed circuit wind tunnels with open and close test sections. The improvement was achieved for several cases by means all of the applied methods.
Řízení mezní vrstvy na profilu s vychýlenou klapkou pomocí vírových generátorů
Součková, Natálie ; Šimurda, David ; Popelka, Lukáš
The paper focuses on reducing eventually removing flow separation, which is occurred on deflected flap, with vortex generators. Airfoil NACA 63A421 with simple flap and low profile vane-type vortex generators were used. The investigation was carried out using experimental and numerical method. The flow over the airfoil was visualized by tuft filaments technique in closed circuit wind tunnel for two flap deflections and four angles of attack. Two size and two different shapes of vortex generators were tested. The data from numerical simulation of flapped airfoil without VG's control were used for vortex generator designing.
Řízení mezní vrstvy na profilu s vychýlenou klapkou pomocí vírových generátorů
Součková, Natálie ; Šimurda, David ; Popelka, Lukáš
The paper focuses on reducing eventually removing flow separation, which is occurred on deflected flap, with vortex generators. Airfoil NACA 63A421 with simple flap and low profile vane-type vortex generators were used. The investigation was carried out using experimental and numerical method. The flow over the airfoil was visualized by tuft filaments technique in closed circuit wind tunnel for two flap deflections and four angles of attack. Two size and two different shapes of vortex generators were tested. The data from numerical simulation of flapped airfoil without VG's control were used for vortex generator designing.
Numerická simulace aerodynamické interakce křídla a trupu
Šimurda, David ; Popelka, Lukáš ; Zelený, L. ; Matějka, Milan
In order to investigate and understand extent of the wing-body interaction effects taking place during operation of a particular self-launching sailplane, commercial code Fluent 6.3 was used for numerical simulation of flow past a simplified model of TST-10a. Several methods were used to identify vortex structures originating due to interference effects in this part of the aircraft. 3D effects and distortions of pressure and velocity distributions taking place in the junction of the body and the fuselage were observed.
Měřicí prostor pro profily a tělesa, studie proveditelnosti výzkumného projektu
Popelka, Lukáš
Article describes new 865x485x900mm3 test section of closed-circuit wind tunnel IT AS CR for airfoils and bodies, respectively. These setups are arranged primary for three-component aerodynamic balance and visualization techniques access. Prepared research programme aimed at reference measurements, outer stream turbulence, flow control and surface roughness influence on boundary layer transition and separation is presented.
Analýza aerodynamické optimalizační funkce, řízení a zviditelnění proudění na profilech s jednoduchou klapkou pro aplikace na větroních třídy FAI 18m
Popelka, Lukáš ; Krejčiřík, P. ; Matějka, Milan ; Jensen, R.
Aerodynamic criteria for assessing the performance of flapped airfoils applicable on wings of FAI 18m sailplanes were established by a questionnaire survey. CFD methods were used to calculate values of the criteria. Procedure of target function evaluation, enabling to take into account optimum flap deflection was developed and used for five different airfoils, typical for contemporary top-performance sailplanes. Possibility of drag coefficient reduction by transition control on the lower surface, while flap setting for circling, was studied. Surface flow visualization and integrating rake pressure measurement for optimum transition control was carried out on a high-performance sailplane HPH304S.
Nestacionární charakteristiky rovinného paprsku, vstřikovaného do korátkové kavity
Knob, Martin ; Uruba, Václav ; Antoš, Pavel ; Popelka, Lukáš ; Šafařík, Pavel ; Adamec, J.
In the article, the results of the biorthogonal decomposition of a 2D TR PIV data of a jet impinging into a trough cavity, are presented. The obtained spatiotemporal structure is shown and its physical meaning is clearly explained.
Řízení přechodu a odtržení mezní vrstvy na profilech a tělesech za podmínek volné atmosféry
Popelka, Lukáš ; Zelený, L.
The paper deals with visualisation of uncontrolled and controlled cases of boundary layer transition and separation carried out during in-flight measurements. Oil flow and tuft techniques have been applied. Influence of passive flow control devices to the performance of the entire aircraft has been established and importance of active and adaptive approach shown.
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.

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