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The effect of using the Kline-Fogleman modification upon the coefficient characteristics of aerodynamic forces in the airfoil

Szczepaniak R., Bąbel R., Grzywacz A., Stryczniewicz W., Kowaleczko G.

Journal of KONES

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2018

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Vol. 25, No. 2

349--356

EN

The wing is the main aircraft construction element, whose main task is to produce the lift, balancing the aircraft weight as well as ensuring the execution of all flight states for which the aircraft was designed. The selection of appropriate airfoils or the development of new ones is one of the most important constructions goals. As a rule, constructors aim at ensuring a sufficiently large lift with little aerodynamic drag in order to increase the scope of utility angles of attack and such shaping of these characteristics so that the aircraft performance, close to the critical angles of attack, guarantees an adequate level of safety. One of the methods of improving the aerodynamic properties of airfoils is the Kline-Fogleman modification. It involves an application of a step into the airfoil contour at a place. It enforces the creation of a swirling air stream, preventing the separation and maintaining airflow over the profile and thus the reduction of drags, as well as delaying separation. The use of this type of a solution is justified when designing unmanned aerial vehicles, of small sizes, which move with slow speeds and sometimes-large angles of attack, including those close to critical angels of attack. The Kline-Fogleman modification decreases the likelihood of aircraft stalling. The aim of this work is to present an analysis of airflow over NACA0012 airfoil with Kline-Fogleman modification. The calculations were made by solving the problem of numerical fluid mechanics. For calculations, the Comsol Maribor programme was used. The investigation focused on several different airfoil modifications (KFm-1, KFm-2, KFm-3). This enabled a selection of a solution, providing the most desirable aerodynamic characteristics.

2

Flow visualization over an airfoil with flight control surfaces in a water tunnel

Filipiak D., Szczepaniak R., Zahorski T., Bąbel R., Stabryn S., Stryczniewicz W.

Prace Instytutu Lotnictwa

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2017

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Nr 1 (246)

63--78

EN

This paper demonstrates the feasibility of using-a water tunnel for the visualisation of flow in airfoils with flight control systems in the form of slots and flaps. Furthermore, the issue of using water tunnels for scientific and training purposes was explained. The technology of 3D printed models for practical tests in a water tunnel was also presented. The experiment included conducting flow visualisation tests for three airfoil models: with the Clark Y 11.7% as the base airfoil and the same airfoil with a slot and a flap. Moreover, a modification to dye injection system was introduced. The presented results of flow visualisation around models with the use of dye, confirmed the effectiveness of the applied methodology. The results and conclusions may be utilized to verify most flow-related issues in hydrodynamic tunnels and can also be used as a training element.

PL

W pracy przedstawiono uzasadnienie możliwości zastosowania tunelu wodnego do wizualizacji przepływu modeli profili lotniczych z mechanizacją w postaci slotów i klap. Ponadto przybliżono tematykę zastosowania tuneli wodnych w celach naukowych jak i szkoleniowych. Przedstawiono również technologię wydruku 3D modeli do testów praktycznych w tunelu wodnym. Eksperyment obejmował przeprowadzenie badań wizualizacyjnych dla trzech modeli profilu lotniczego: jako bazowy profil Clark Y 11.7% oraz ten sam profil ze slotem i z klapą. Ponadto autorzy pracy wprowadzili modyfikację wprowadzania barwnika przed badany model geometryczny umiejscowiony na trzymaku w przestrzeni pomiarowej. Przedstawione wyniki zobrazowania przepływał w:okół modeli za pomocą barwnika potwierdziły skuteczność zastosowanej metodyki prowadzenia eksperymentu na charakterystycznych kątach natarcia. Wyniki i wnioski można wykorzystać do zweryfikowania większości zagadnień przepływowych w tunelach hydrodynamicznych jak również mogą posłużyć jako element szkoleniowy.

3

Water tunnel visualisation and numerical analysis of flow around TS-11 Iskra wing with flow control surfaces

Szczepaniak R., Walusiak S., Bąbel R., Mazurek Ł, Stryczniewicz W., Kowaleczko G.

Journal of KONES

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2017

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Vol. 24, No. 2

253--261

EN

The article presents investigation of flow around wing of TS-11 Iskra airplane. The flow visualization around 3D printed model of wing with flow control surfaces was performed in a water tunnel. Two configurations were investigated: first with a flap and second with an aileron. The flow visualisation was performed with a use of a dye. The geometry of model was prepared with use Computer Aided Design (CAD) software basing on scans of real object and technical documentation. The model was built with use of additive manufacturing technology. Movement of the flow control surfaces was remotely controlled with servomechanisms incorporated in channels inside the model. In order to perform qualitative validation of the results the investigated flow was simulated with use of CFD commercial software. The article presents visualisation results of flow around wing section of TS-11 Iskra airplane and water tunnel model preparation. In order to perform qualitative validation of the results the investigated flow was simulated with use of CFD commercial software. The goal of the research was to investigate the complex flow field in the vicinity of flow control surfaces and provide aerodynamic characteristics at various deployment angles via numerical simulations. The results can be used for verification of water tunnel testing procedures and training.

4

CFD analysis of the influence of flaps extension on the aerodynamic characteristics of the M-28 Bryza aircraft

Szczepaniak R., Konopka B., Zahorski T., Bąbel R., Stryczniewicz W.

Journal of KONES

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2016

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Vol. 23, No. 1

353--360

EN

The paper presents a modelling procedure of the M-28 Bryza wing with extended flaps and Computational Fluid Dynamics (CFD) simulations results preformed in order to assess the performance of the investigated wing for various flap extension rates. The M-28 Bryza is a two-engine high-wing aircraft used in the Polish Air Force for short distance airlift of people and equipment. The aim of this work was to determine the aerodynamic characteristics of the investigated wing. The CFD simulations were performed in order to investigate the influence of flap extension on lift and drag coefficients at various angles of attack. In order to validate the results of two different commercial CFD packages were used. The findings are presented in the form of flow visualization and aerodynamic characteristics. The typical and non-standard extension rates were investigated for low, moderate and high angles of attack. The results correlated with the limitations specified in the aircraft manual. The outcome of the presented work confirmed the feasibility of the presented methodology for its use as a supportive tool for providing additional information about airplane performance in standard and non-standard conditions of flight such as landing with one engine working. The results of work might prove useful for M-28 Bryza pilots and maintenance personnel as well as for educational purposes.