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Numerical Simulation of Turbulent Flow Affected by Vortex Generators in Straight Channel
Součková, Natálie ; Šimurda, David ; Uruba, Václav
The presented work is the next step after several experimental examinations of the vortex generator (VG) influence on flow separation occurring on a model of the NACA 63A421 airfoil with a deflected simple flap. The other purpose of this simulation is to obtain beneficial information that can be utilized for the preparation of the experimental investigation of the same configuration using Particle Image Velocimetry method (PIV) in the future. The numerical simulation was performed for one single pair and two pairs of low-profile VGs of the same size, whose heights were smaller than the boundary layer thickness. The rectangular vane type VGs in such configuration, which generates counter-rotating vortices, was examined. The behaviour of vortices produced by VG pair or pairs in several positions downstream the VGs is investigated and will be used as a background of the measurement.
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Visualisation of Boundary Layer Separation and Passive Flow Control on Airfoils and Bodies in Wind-Tunnel and In-Flight Experiments
Popelka, Lukáš ; Kuklová, J. ; Šimurda, David ; Součková, Natálie ; Matějka, Milan ; Uruba, Václav
Infrared camera, Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds numbers transition mechanism. Airfoils of Wortmann FX66 series and FX66 series wing-fuselage interaction, as well as modern airfoils and their wing-fuselage geometry were subject to study. The presence of previously identified structures in the CFD modelling, such as horse-shoe vortices, was confirmed in the flow.
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Charakterizace rodiny proteinů o molekulové hmotnosti 18,7 a 19 kDa ze slinných žláz klíštěte \kur{Ixodes ricinus}
SOUČKOVÁ, Nina
Podařilo se vytvořit rekombinantní protein c90 a polyklonální protilátky proti tomuto proteinu. Byla připravena dvouvláknová RNA pro pokusy s RNA interferencí. Z tkání získaných z klíšťat napíchaných touto dsRNA po pěti dnech sání byly připraveny vzorky pro RT-PCR a Western blot. Dosažené výsledky naznačovaly, že protein c90 se uplatňuje v těle klíštěte v reakci na poranění, a proto byl uskutečněn pokus s klíšťaty napíchanými vodou, G+ bakteriemi a G- bakteriemi. V průběhu získávání dat pro tuto diplomovou práci bylo zjištěno, že zkoumané proteiny mají schopnost tvořit multimery, a že při RNA interferenci nedochází k vypnutí genu, ale naopak k jeho upregulaci. Ve světle těchto informací společně s bioinformatickou analýzou vyvstává možný závěr, že proteiny o molekulové hmotnosti 18,7 a 19 kDa jsou pravděpodobně důležité ve fyziologii klíštěte. Tyto proteiny mají s největší pravděpodobností strukturní funkci v těle klíštěte a jejich produkce může být reakcí na poranění, v případě RNAi vpichu, spíš než v antiimunitě. Současně ale i skutečnost, že u normálního klíštěte jsou proteiny 18,7 kDa exprimované ve větší míře na začátku sací periody nabízí k úvaze to, že i v hostiteli mají tyto proteiny přece jen svou funkci.
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PASSIVE CONTROL OF BOUNDARY LAYER TRANSITION AND SEPARATION
Popelka, Lukáš ; Matějka, M. ; Šimurda, David ; Součková, Natálie
Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds number transition mechanism. Airfoils of three Czech-designed sailplanes and their wing-fuselage interaction were subject to study. Experimental data were coupled with numerical modeling and synthesis gained. Effect of passive flow control devices - vortex generators - was surveyed, counter-rotating vortex generators and Zig-zag type turbulators were applied. Separation suppression was reached and consequent drag coefficient reduction of test aircrafts measured in flight. Investigation was further extended by PIV Time-Resolved technique.
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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.
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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.
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Řízení mezní vrstvy na profilu s vychýlenou klapkou pomocí vírových generátorů
Součková, Natálie ; Šimurda, David ; Popelka, Lukáš
Práce je zaměřena na odstranění odtržení na vychýlené klapce pomocí vírových generátorů. Experimentální a numerické řešení tohoto problému bylo provedeno na profil NACA 63A421 s jednoduchou klapkou. Vírové generátory s výškou mnohem menší než je výška mezní vrstvy byly použity. V rámci experimentu bylo provedena vizualizace proudění pomocí bavlnek při dvou výchylkách klapky a čtyřech úhlech náběhu. Testovány byly dva různé tvary vírových generátorů a dvě velikosti. Numerická simulace byla použita pro návrh vírových generátorů.
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