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Wing leading edge active flow concept analysis
Mahdal, Vít ; Zikmund, Pavel (referee) ; Popela, Robert (advisor)
This research is focused on substitution of commonly used High-Lift devices by active flow control on the wing leading edge. The analysis is done by CFD tools with use of Reynolds-Averaged Navier-Stokes (RANS) method. In the beginning of the research, commonly used High-Lift devices are described. Solver setting and its explanation together with verification and validation is described in the following chapters. An active flow control concept is testing at the LS(1)-0413 airfoil, for 5 different positions of slots, two different slots widths (h/c= 0,0025 and 0,005) and two different blowing velocities (v_Jv_=2,22 and 4,44). In the end of this paper, physical phenomena of blowing is described together with evaluation of different cases. The best case is compared with Fowler and slotted flap at Reynolds number 2,2 million.
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Anisotropy of Turbulent Flow around an Airfoil
Uruba, Václav ; Procházka, Pavel P. ; Skála, Vladislav
The flow around an airfoil is analyzed from the point of view turbulence anisotropy assessment. The turbulent flow-field in the vicinity of an airfoil is populated by vortices, in some locations they tend to regularity in orientation, i.e. to anisotropy. However in the wake behind the plate as well as in the core of the boundary layer on the plate suction side the turbulence is close to isotropic state.
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Structure of the Wake Behind an Airfoil
Uruba, Václav ; Procházka, Pavel P. ; Skála, Vladislav
The wake behind an inclined plate simulating airfoil is to be studied experimentally. The vortical structures are identified eventually. Theirs topology and dynamical behaviour is to be studied in details using the Proper Orthogonal Decomposition method. The stereo time resolved Particle Image Velocimetry technique is used for the experimental research. The vortex trains with oblique orientation and chequered topology have been detected.
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Self-excited oscillation properties of the profile NACA0015 in subsonic flow
Zolotarev, Igor ; Vlček, Václav ; Kozánek, Jan
Self-excited oscillations of the profile NACA0015 in subsonic flow were realized in the wind tunnel. The plunge support had the same elasticity for all experiments, the pitch support had seven different elasticity parameters. During our experiments different types of selfexcited vibration (flutter, stall flutter) were observed. Range of Mach numbers was M = 0.08–0.45, corresponding range of Reynolds numbers is Re = (1–5)·105, when the chord length is used as the characteristic dimension of the profile.\n
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Some experimentally determined properties of a profile in case of self-excited oscillations in subsonic flow
Vlček, Václav ; Zolotarev, Igor ; Kozánek, Jan ; Šidlof, Petr ; Štěpán, M.
In the wind tunnel of the Institute of Thermomechanics of the AS CR,v .v. i., experiments were realized with the profile NACA0015 in the presence of the self-excited oscillation. The oscillation of the profile with pitch and plunge degrees of freedom was excited by the subsonic air flow. The plunge support had the same elasticity for all experiments, the pitch support had seven different values of elasticity. Within experiments different types of self-excited vibration (flutter, stall flutter, deep stall flutter) were realized. Range of Mach numbers were M=0.08–0.45, when the chord length is used as the characteristic dimension of the profile. The frequency and amplitude characteristics of the oscillating profile were experimentally determined.\n
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Dynamics of Coherent Structures Behind Vibrating Airfoil
Uruba, Václav
Flow around steady and vibrating airfoil with a positive angle of attack has been\nstudied experimentally, using a Time-Resolved PIV (“TR-PIV”) technique. For analysis of\ncomplex spatial dynamics of the flow the Oscillation Pattern Decomposition (OPD) method\nhas been used. The resulting flow dynamics is characterized by OPD modes of oscillating and\nnon-oscillating character, describing travelling and pulsating patterns in the flow. Topology\nand frequency of dynamic modes are shown in the presented paper.
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Force interaction of an airfoil in fluid flow
Uruba, Václav
The physical mechanism of lift and drag forces exerted on an airfoil is studied using results from mathematical modelling. Special attention is paid to lift force origin. The mechanism based on 3D flow-structure as a result of 2D flow-field instability is described.
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High performance paraglider aerodynamic optimization
Grim, Robert ; Navrátil, Jan (referee) ; Popela, Robert (advisor)
This thesis is focused on the aerodynamic analysis of the competition paraglider wing. Drags of the particular wing parts are divided into chapters. The aim was to get a grasp of sizes of the individual components drags in relation to the entire assembly. In the first instance, a 2D profile and then the entire configuration of the 3D wing was analyzed. After the evaluation, some power reserves were detected in an airfoil and so the airfoil shape was optimized. After the optimization of the individual components, the CFD calculation was used again. At the end, geometry changes were evaluated.
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Aerodynamics Parametric Shape Aircraft Optimization
Dofek, Ivan ; Salga, Jaroslav (referee) ; Brož,, Václav (referee) ; Fiľakovský, Karol (advisor)
The work deals with the use of geometric parameterization for shape description of some parts of the airplane. Geometric parametrization is used for creating a parametric model airfoil. This parametric model allows local deformations pobrchu profile and can easily be applied to generate the geometry of the wing or other parts letoumu. Some properties of the parametric model were tested applications in aerodynamic optimization. Furthermore, the work deals with the parametric description of the blades, the aerodynamic optimization and noise analysis. For propeller blade were created distribution function of the control parameters that can be used in aerodynamic optimization of the blades. Geometric parameterization is used for identifying the location and other characteristics of noise sources.
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