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Measurements of 3D Flow Field Behind the Blade Cascade SE 1050
Šimurda, David ; Luxa, Martin
The paper is concerned with measurements of 3D flow field at exit of the Blade Cascade SE1050. Data was collected using traversing device with a small five-hole conical probe. Prior to measurements of the flow exiting the blade cascade, investigations of inlet velocity profile and inlet turbulence intensity were conducted. Measurements of exit flow field were performed at design angle of incidence and at a transonic and a subsonic regime. Data analysis reveals development of distinctive vortex structures resulting from non-uniform inlet velocity profile. Origin of these structures results in increased loss of kinetic energy and spanwise shift of kinetic energy loss coefficient distribution.
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Span-Wise Distribution of Losses in Prismatic Turbine Cascade
Fürst, J. ; Luxa, Martin ; Šimurda, David
The paper deals with the experimental and numerical research of flows through prismatic turbine cascade in transonic regimes. The primary goal is to evaluate the influence of the non-uniformity of the inlet velocity profile to the spanwise distribution of energy losses. The numerical simulation with inlet velocity profile corresponding to the parameters of the flow in high speed wind tunnel in Nov´y Kn´ın is compared to the experimental data. Next, the simulation assuming different inlet velocity profiles are used to evaluate the effect of the boundary layer in front of the cascade to the span-wise distribution of energy losses.
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Numerické řešení stlačitelného proudění v turbinové mříži pomocí různých modelů přechodu do turbulence
Nádvorník, M. ; Straka, P. ; Příhoda, Jaromír
Příspěvek se zabývá numerickou simulací 2D stlačitelného proudění v přímé turbinové mříži. Výpočty byly provedeny vlastním výpočetním programem založeným na dvourovnicovém k-w modelu turbulence s algebraickým modelem přechodu a komerčním software Fluent pomocí třírovnicového modelu turbulence včetně přechodu podle Walterse a Cokljata. Výpočty, provedené pro různá Reynoldsova a Machova čísla, zahrnují přechod v přilehlém i odtrženém proudění. Vypočtené hodnoty ztrátového součinitele a výstupního úhlu proudu byly porovnány s experimentálními daty, získanými pro turbinovou mříž VS33.
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Numerical simulations of turbulent flow through DCA 8% cascade
Trefilík, Jiří ; Kozel, K. ; Příhoda, Jaromír
The work deals with further development of numerical methods for simulation of transonic turbulent flows through the DCA 8% cascade. Results of numerical experiments modelling the viscous and inviscid flows in a cascade with various inlet Mach numbers are compared and discussed. For turbulence modelling the algebraic Baldwin-Lomax model and two- equation standard k-ω and TNT k-omega models were employed.
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Numerical experiments for turbulent flows
Trefilík, Jiří ; Kozel, Karel ; Příhoda, J.
The aim of the work is to explorethe possibilities of modelling transonic flowsin the internal and external aerodynamics. Several konfigurationswere analyzed and calculations were performed using both inviscid and viscous models of flow. Viscous turbulent flows have been simulated using either zero equation algebraic Baldwin-Lomax model and two equation k - w model in its basic version and improved TNT variant. The numerical solution was obtained using Lax-Wendroff scheme in the MAcCormack from on structured non-ortogonal grids. Artificial dissipation was added to improve the numerical stability. Achieved results are compared with experimental data.
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Aerodynamics tests of a transonic turbine blade cascade model consisting of low number of blades
Šimurda, David ; Luxa, Martin ; Šafařík, Pavel ; Synáč, J.
Contribution is concerned with experimental investigation of the transonic turbine blade cascade aerodynamic characteristics. Due to specific geometry of the blade cascade, the blade cascade model consists of six blades only. Therefore, special experimental setup is adopted and its influence on the resultant blade cascade aerodynamic characteristics is discussed. Experimental data are obtained applying both optical (interferometry, schlieren technique) and pneumatic methods (mainly traversing with a five-hole conical probe). Special attention is paid to flow structures, which significantly contribute to the increase of kinetic energy loss coefficient. Results of current investigation are compared to former results obtained at usual experimental set-up.
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Vortex lift and insect flight
Dvořák, Rudolf
Vortex lift is usually associated with swept wings at high angles of attack. Insect wings oscillating at high frequencies develop a leading edge vortex which behaves at very low Reynolds numbers in the same way as on swept wings. Results are of interest for design of MAV (micro-air-vehicles).
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Modelling of the effect of the foregoing wake on the bypass transitionon the airfoil
Straka, P. ; Příhoda, Jaromír ; Šimurda, David
A modified algebraic model of the bypass transition was used for the simulation of the flow around the symmetrical airfoil NACA 0012 in the tandem configuration. The transition model is based on local variables only to enable its application for complex flow geometry using unstructured computational grids. The attention was especially focused on the flow near the leading edge where the boundary layer is not yet fully developed while used empirical correlations were established for the boundary-layer flow. The numerical simulation was compared with experiments of Lee and Kang (2000) carried out for the Reynolds number Re = (2x6)x10^5, the zero angle of attack and various distance between both airfoils. The agreement of numerical simulation with experimental data is quite satisfactory.
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Experimental simulation of inviscid and viscous turbulent transonic flows
Trefilík, Jiří ; Kozel, K. ; Příhoda, Jaromír
The work deals with the development of numerical methods for simulation of transonic turbulent flows through the DCA 8% cascade and over the 18% thick circular arc biconvex airfoil. Results of numerical experiments modelling the viscous and inviscid flows in the cascade with the inlet Mach numbers M = 0.87 and 0.96 and over the airfoil with M =0.775 are compared and discussed. The two-equation k-omega model and the algebraic Baldwin-Lomax model were employed for turbulence modelling and their numerical results were compared.
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