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Wyszukujesz frazę "transonic flow" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Turbulent triggers and the model quality influence on aerodynamic characteristics of the laminar aerofoil in transonic flow regime
Autorzy:
Placek, Robert
Ruchała, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/245279.pdf
Data publikacji:
2019
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transonic flow
aerofoil
model quality
aerodynamic characteristics
shock wave
Opis:
The test with a roughness application on the laminar aerofoil has been conducted in the N-3 trisonic wind tunnel of the Institute of Aviation in Warsaw. The main goal of tests was to investigate the influence of the boundary layer transition triggers on a laminar profile aerodynamic characteristic. For baseline configuration, the natural transition was applied. As a local roughness on the upper model surface, the carborundum strips with different heights were applied. These were positioned on the upper model surface in the front of the shock position occurrence. The Mach number during test was equal Ma = 0.7 and Reynolds number was about 2.85·106 . Tests have been conducted for different model incidence in range 0º-7º. Current article refers partially to the previous study, where aerofoil model with lower quality of surface had been tested. Investigation results from previous work indicated that some of transition positions improved an aerodynamic characteristic by reducing the drag coefficient value and decreasing shock wave unsteadiness in the transonic regime. However, current article indicates that beneficial effects in respect to the baseline configuration are also strictly dependent on the model quality and turbulent triggers size. Improved surface quality of the laminar aerofoil model affected on aerodynamic characteristics with and without turbulent triggers. Resultant aerodynamic coefficients of all tested cases i.e. drag, lift and lift to drag ratio were compared.
Źródło:
Journal of KONES; 2019, 26, 3; 165-172
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PIV measurements of flow separation over laminar airfoil at transonic speeds
Autorzy:
Stryczniewicz, W.
Placek, R.
Szczepaniak, R.
Powiązania:
https://bibliotekanauki.pl/articles/247542.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
shock wave
transonic flow
boundary layer separation
Particle Image Velocimetry
Opis:
The paper presents results of transonic flow field visualization over a laminar airfoil in high-speed wind tunnel. Quite recently, considerable attention has been paid to experimental investigations of an interaction between the shock and the boundary layer for aerodynamics applications. The purpose of the paper is to investigate development of the flow separation over laminar airfoil at transonic speeds. In a course of presented studies, the Particle Image Velocimetry (PIV) method was used for instantaneous velocity measurements of flow field in the test section of N-3 Institute of Aviation transonic wind tunnel. The object of the research was a laminar airfoil inclined at various angles. The effect of the varying angle of incidence on the flow filed was investigated. The freestream Mach number was 0.7. The results of the PIV measurements were analysed in order to identify the type of the separation from the measured velocity fields. Three forms of separation for low, medium and high angle of incidence was distinguished. The results are in good agreement with theoretical models reported in the literature. The study showed that application of quantitative flow visualisation technique allowed gaining new insights on the complex phenomenon of transonic flow over airfoil. The results of the presented research can be used for better understanding of the mechanism of the flow separation process in transonic flow over airfoils and fluid structure interactions.
Źródło:
Journal of KONES; 2016, 23, 1; 329-335
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of the boundary layer shock wave interaction type in transonic flow regime
Autorzy:
Placek, R.
Stryczniewicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/242396.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transonic flow
wind tunnel techniques
shock wave
airfoil
boundary layer interaction
Opis:
The paper presents various approaches to wind tunnel data analysis when identifying the shock wave boundary layer interaction type. The investigation was carried out in the transonic flow regime in the N-3 Wind Tunnel of Institute of Aviation. The Mach number was 0.7 and Reynolds number was approximate equal 2.85 million. The object of the research was a laminar airfoil in configuration without and with turbuliser device mounted on the upper model surface. In order to achieve turbulent boundary layer in front of the shock wave the carborundum strip was used. The effect of the varying angle of incidence on the flow filed was investigated. During experimental research, different means and test methods were applied (pressure measurements, Schlieren and oil visualisation, Particle Image Velocimetry (PIV), hot-film anemometry). The results were analysed in terms of the shock wave boundary interaction type. Most of results were in good agreement with theoretical models reported in the literature. The study showed that combination of various measurement techniques should be used in the shock wave boundary investigations in order to achieve more consistent and reliable conclusions. The results of the presented research can also be used for better understanding other mechanisms i.e. the boundary layer shock wave separation process in transonic flow regime.
Źródło:
Journal of KONES; 2016, 23, 2; 285-292
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shock wave induced flow separation control by Air-Jet and Rod Vortex Generators
Autorzy:
Tejero, F.
Doerffer, P.
Szulc, O.
Powiązania:
https://bibliotekanauki.pl/articles/1938633.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska
Tematy:
airfoil
boundary layer
flow control
separation
shock wave
transonic conditions
vortex generator
Opis:
Flow separation control by Vortex Generators (VGs) has been analyzed over the last decades. The majority of the research concerning this technology has been focused on subsonic flows where its effectiveness for separation reduction has been proven. Less complex configurations should be analyzed as a first step to apply VGs in transonic conditions, commonly present in many aviation applications. Therefore, the numerical investigation was carried out for a Shock Wave-Boundary-Layer Interaction (SWBLI) phenomenon inducing strong flow separation at the suction side of the NACA 0012 profile. For this purpose, two kinds of VGs were analyzed: well documented Air-Jet Vortex Generators (AJVGs) and our own invention of Rod Vortex Generators (RVGs). The results of the numerical simulations based on the RANS approach reveal a large potential of this passive flow control system in delaying stall and limiting separation induced by a strong, normal shock wave terminating a local supersonic area.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2015, 19, 2; 167-180
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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