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Numerical Study of the Effect of the Trailing-Edge Devices (Gurney Flap and Divergent Trailing-edge Flap) on the Aerodynamic Characteristics of an Airfoil in Transonic Flow for Drone Applications

Kmiotek Małgorzata, Kordos Adrian, Piszczatowski Adam, Zaremba Adam

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 5

248--259

EN

The aim of this study was to investigate the effects of mini Trailing-Edge Devices (mini TEDs) on the aerodynamic characteristics of the RAE 2822 airfoil. Using ANSYS Fluent software, numerical simulations were conducted to analyze the compressible flow around the airfoil at Mach number (Ma) 0.73, considering different angles of attack. The mini TEDs used in the simulation were a Gurney flap and a divergent trailing-edge. The results show that the integration of these mini TEDs at the trailing edge leads to a significant increase in both lift coefficient (CL) and drag coefficient (CD) but, for certain angles of attack, an improvement in the lift-to-drag ratio of the airfoil was obtained. The results showed the potential benefits of using mini TEDs to improve aerodynamic performance in aerospace drone applications.

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Turbulent triggers and the model quality influence on aerodynamic characteristics of the laminar aerofoil in transonic flow regime

Placek Robert, Ruchała Paweł

Journal of KONES

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2019

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Vol. 26, No. 3

165--172

EN

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.

3

PIV measurements of flow separation over laminar airfoil at transonic speeds

Stryczniewicz W., Placek R., Szczepaniak R.

Journal of KONES

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2016

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Vol. 23, No. 1

329--335

EN

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.

4

Identification of the boundary layer shock wave interaction type in transonic flow regime

Placek R., Stryczniewicz W.

Journal of KONES

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2016

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Vol. 23, No. 2

285--292

EN

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.

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Application of hybrid CFD/CAA technique for modeling pressure fluctuations in transonic flows

Dykas S., Wróblewski W., Rulik S.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2013

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Vol. 17, No 3-4

145--154

EN

Solving AeroAcoustics (CAA) problems by means of the Direct Numerical Simulation (DNS) or even the Large Eddy Simulation (LES) for a large computational domain is very time consuming and cannot be applied widely for engineering purposes. In this paper in-house CFD and CAA codes are presented. The in-house CFD code is based on the LES approach whereas the CAA code is an acoustic postprocessor solving non-linearized Euler equations for fluctuating (acoustic) variables. These codes are used to solve the pressure waves generated aerodynamically by a flow over a rectangular cavity and by the vortex street behind a turbine blade. The obtained results are discussed with respect to the application of the presented numerical techniques to pressure waves modeling in steam turbine stages.

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Research on steam condensing flows in nozzles with shock wave

Dykas S., Majkut M., Smołka K., Strozik M.

Journal of Power Technologies

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2013

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Vol. 93, nr 5

288--294

EN

The paper presents experimental and numerical results of steam transonic flows in Laval nozzles. The geometries of half arc nozzles were used in testing. Subject to investigation was the behavior of shock waves in the wet steam region. Due to high back pressure the shock wave was created in the divergent part of the nozzle, and interaction with the nozzle walls caused instability in the flow. The experimental results were compared with numerical calculations of steam condensing transonic flow.

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Aerodynamic Research on the Midsection of a Long Turbine Blade

Šimurda D., Luxa M., Šafařík P., Synáč J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2008

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Vol. 12, No 3-4

135-145

EN

The paper is concerned with experimental aerodynamic research on the midsection of a 1220mm long turbine rotor blade. Optical as well as pneumatic measurements of the midsection blade cascade have been performed in a suction type high-speed wind tunnel. The results of measurements are analyzed and discussed. Interferograms and schlieren pictures taken in a wide range of isentropic exit Mach numbers and incidence angles exhibit the existence of several phenomena occurring in the transonic flow field at certain conditions concerning the exit Mach number and the angle of incidence. A flow separation taking place at an extreme negative incidence has been found to produce an additional loss of 6%. The presence of the reflection of an exit shock wave on the suction side of the neighbouring profile has been found to have a substantial influence on the losses, since the loss coefficient value has increased about 10% in cases without the reflection, i.e. the cases at a high exit Mach number and a high positive angle of incidence. Several reflection types have been observed and described.

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Numeryczna symulacja dwuwymiarowego, niestacjonarnego przepływu transonicznego

Stalewski W.

Prace Instytutu Lotnictwa

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2004

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Nr 2-3 (177-178)

72-85

PL

W pracy przedstawiono metodę numerycznej symulacji niestacjonarnego przepływu transonicznego wokół profilu lotniczego. Metoda oparta jest na sprzęgnięciu nielepkiego przepływu zewnętrznego z lepkim przepływem wewnątrz warstwy przyściennej rozciągającej się przy powierzchni profilu oraz wzdłuż śladu wirowego. Fizyczny model przepływu zewnętrznego bazuje na niestacjonarnym, pełnym równaniu potencjału, które rozwiązywane jest metodą różnic skończonych. Równania ściśliwej warstwy przyściennej rozwiązywane są w postaci całkowej jako układ równań różniczkowych zwyczajnych. Postać tego układu jest różna w zależności od charakteru przepływu w warstwie. W trakcie obliczeń dokonywana jest analiza przejścia laminarno-turbulentnego. Sprzęgniecie przepływu lepkiego wewnątrz warstwy z nielepkim przepływem zewnętrznym realizowane jest na bazie metody pół-odwrotnej. Praktyczna realizacja opracowanej metody - program komputerowy, umożliwia analizę transonicznego opływu profilu zarówno w warunkach w pełni niestacjonarnych jak i stacjonarnych. Program został opracowany jako moduł obliczeniowy pakietu oprogramowania rozwiązującego zagadnienia optymalizacji profili śmigłowcowych. Przedstawiono przykłady obliczeń testowych oraz porównano uzyskane wyniki z rezultatami badań eksperymentalnych.

EN

In the paper is presented a method of digital simulation of non-stationary transonic flow around an airfoil. The method h based on coupling of non-viscous external flow with viscous flow in the boundary layer located at the airfoil surface and along vortex track. Physical model of the external flow is based on non-stationary, complete equation of potential, which is solved with the use of finite difference method. Equations of compressive boundary layer are solved as integrals of a system of normal differential equations. The form of this equation system is various and depends on character of the flow in the boundary layer. Within calculations an analysis of laminar-turbulent transformation is being performed. Coupling of the viscous flow in the boundary layer with non-viscous external flow is based on a semi-reverse method. Practical realization of the elaborated method is a computer program, which enables an analysis of transonic flow around an airfoil both in completely non-stationary and stationary conditions. The program was elaborated as a computational module of a program package solving problems of optimization of helicopter airfoils. Examples of test calculations are presented and the obtained results are compared to results of experiments.

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Instalacja do badania przepływu pary przegrzanej i mokrej ze zjawiskami kondensacji

Mańka G., Łukowicz H., Werbowski T., Wróblewski W., Dykas S.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2001

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z. 15

215-220

PL

W artykule przedstawiono koncepcję stanowiska pomiarowego do badania przepływów pary wodnej przez dysze i kanały łopatkowe, metodykę i zakres pomiarów, uzyskane wstępne wyniki badań oraz przykłady otrzymanych wizualizacji zjawiska kondensacji. Przedstawione wyniki badań eksperymentalnych potwierdzają celowość budowy stanowiska. Uzyskana wysoka zgodność rezultatów obserwacji z przyjętym modelem numerycznym pozwala przypuszczać, że w miarę gromadzenia większej ilości wyników doświadczeń możliwa będzie dokładna analiza ich porównania z opracowanym w Instytucie algorytmem obliczeniowym.

EN

The article shows a concept of measuring stand for studies of steam flow through nozzles and blade channels, methods and scope of measurements, obtained initial results and visualization examples of condensation phenomena. The presented experiment results support purposefulness of stand construction. High fidelity of obtained results with assumed numerical model allows to presume that along with a growing amount of data from further experiments, a more detailed analysis of their comparison with our Institute's numerical algorithm should be possible.

10

Flow simulation at shock wave triple point

Doerffer P., Namieśnik K., Magagnato F.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2001

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Vol. 5, No 4

549-556

EN

The paper presents supersonic flow simulation results concerning the lambda-foot formation in the divergent nozzle. The SPARC code was used and the vicinity of the triple point was analysed. Special boundary conditions have been used in order to obtain supersonic inlet velocity with shock wave in the divergent nozzle. It was proved that the condition of pressure equality on both sides of shear layer following the triple point for flow parameter of interest, does not hold.

11

Transoniczny opływ profilu w warunkach zmiennej wilgotności powietrza

Nosal Z., Selerowicz W.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2000

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nr 117, vol. 1

85-90

PL

W pracy przedstawiono wyniki badań doświadczalnych transonicznego opływu profilu NACA0012 powietrzem wilgotnym. Obejmowały one pomiary ciśnień oraz wizualizacje pola przepływu. Przebadano pełny zakres wilgotności powietrza dla dwóch typowych przypadków transonicznego opływu profilu: z falą uderzeniową o średniej intensywności oraz z falą intensywną i wynikającym z tego oderwaniem warstwy przyściennej.

EN

Results of experimental investigations concerning transonic humid flow over NACA0012 airflow are presented. Pressure measurements and flow visualizations were made. Two typical cases of transonic flow in a wide range of air humidity were studied. The first one with a presence of a shock of middle intensity and the second one with a strong shock forcing boundary layer separation.

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Homogeneous / heterogeneous condensation dynamics in turbulent low pressure turbine flows

Winkler G., Heiler M., Schnerr G. H.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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1999

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nr 115

445--456

EN

This paper is dedicated to gain a better understanding of condensation phenomena in turbulent transonic environment. A 2-D finite volume code has been developed that does also include three different condensation models: pure homogeneous, pure heterogeneous and simultaneous homogeneous/heterogeneous condensation, as well as imperfect gas effects. To be applicable to a variety of technical problems, the code has been extended by a low Reynolds number two equation turbulence model [2 , 14] . The results show excellent agreement with experiments. (Applications: steam turbine L, tip section of steam turbine Bak).