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1

Experimental Determination of the Effect of Floats on Aerodynamic Characteristics of the “OSA” Aircraft in Asymmetric Flow

Frant Michał, Wrzesień Stanisław, Majcher Maciej

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2022

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Vol. 13, Nr 1 (47)

27--44

EN

This study provides the results of experimental tests of the effect of floats on the aerodynamic characteristics of the “OSA” plane in an asymmetric flow. The tests were carried out in a low-speed wind tunnel owned by Institute of Aviation Technology, Faculty of Mechatronics, Armament and Aerospace (FMAA), Military University of Technology (MUT, Warsaw, Poland). The model of “OSA” was tested at dynamic pressure q = 500 Pa within the range of slip angles β = -28°÷28°. The tests were carried out for the plane model in the so-called “plain” configuration, i.e. at non-deflected control surfaces and wing mechanisation elements. The model was tested in two variants – with floats and without floats. The effect of deflection of the flaps, ailerons and rudder on the aerodynamic characteristics of the test model was also examined. The obtained values of drag coefficient, lateral force coefficient and yawing moment coefficient are presented in the form of tables and graphs. The tests showed that the floats had a significant impact on the curves of the characteristics. They result in a considerable increase of the value of the drag coefficient and in a deterioration of weathercock stability.

2

Rotors of vertical-axial wind turbines assembled in bearings and aerodynamic characteristics of a blade with unclosed wing profile

Panda Anton, Rozhkova Lyudmila, Kuznetsov Eduard, Nahornyi Volodymyr

Management Systems in Production Engineering

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2022

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nr 4 (30)

298--303

EN

In world practice, traditional blades used in high-speed wind turbines, both horizontal-axial and vertical-axial, have a wing-shaped profile. However, for horizontal-axial wind turbines, blades with such a profile have a fairly narrow range of operating values of the angle of attack of the incoming air flow and a low value of the moment of pulling from place. As for vertical-axial wind turbines, the self-starting of the rotor with wing blades is completely absent and additional devices are needed to start the rotor into operation. In order to ensure the selfstarting of the rotor and the operation of the wind turbine at high and low wind speeds, a new shape of the blade profile was developed, called non-closed wing profile. The concept of the development is that the blade should have a configuration in which the pulling force is involved at the beginning of the movement, and then, with the establishing of the movement, a lifting force would arise, which acquires a prevailing character in the operating mode. The article presents the results of experimental studies of the aerodynamic characteristics of the developed non-closed wing blades. One of the results obtained is to determine the effect of the thickness of the blade profile on the range of values of subcritical angles of attack of the incoming air flow and the differences between the nature and range of changes in the coefficients of lifting force and pulling force in a traditional wing blade and a blade with a non-closed wing profile. Studies of the rotor model of a vertical-axial wind turbine with non-closed wing blades have confirmed the presence of its self-starting and operability even at low wind speeds.

3

Sensitivity of Aerodynamic Characteristics of Paraglider Wing to Properties of Covering Material

Maślanka Paulina, Korycki Ryszard

Autex Research Journal

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2022

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Vol. 22, no. 1

64--72

EN

The paper is theoretically oriented. The main goal is to analyze the sensitivity of aerodynamic characteristics to the properties of the material used for paraglider wing. The paraglider of considerable dimensions is designed without stiffening elements. Thus, the covering material yields adequate pressure distribution between the external and internal parts of the wing. The problem is solved using a geometrical model approximated by the dimensionless coordinates of crucial points and smoothed by spline curves. The finite volume mesh is defined using the Ansys Meshing program. Numerical analysis uses five different covering materials, ranging from the air-impermeable covering to the covering subjected to hydrolytic-mechanical degradation. Optimization of properties of the covering material improves the lift force and the aerodynamic characteristics of the wing. Moreover, numerical modeling is more beneficial and efficient than prototype tests. The obtained pressure distributions and other parameters explain the aerodynamic safety of the paraglider during dynamic conditions of flight.

4

Determining the Aerodynamic Characteristics of a Propeller-Driven Anti-UAV Fighter While Designing Air Propellers

Loginov Vasyl, Ukrainets Yevgen, Popov Viktor, Spirkin Yevgen

Transactions on Aerospace Research

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2021

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Nr 4 (265)

53--67

EN

Given the rising importance of unmanned aerial vehicles (UAVs), this article addresses the urgent scientific problem of determining the aerodynamic characteristics of a UAV while laying out the propellers for the wings. We discuss the methodology for experimental wind-tunnel studies of aircraft configurations with propellers. It is shown that a characteristic feature of the configuration small-elongation wing with propellers is the absence of elements that are not affected by propellers. This feature makes it difficult to implement and automate a wind tunnel experiment, since there are problems with providing similar criteria for a working propeller; it is difficult to achieve perfect balancing for solid drive propellers, which causes vibration, the level of which depends on uncontrolled factors; the inability to neglect the presence of the body elements influence to the blades of propellers; the difficulty of direct measuring propeller thrust and torque. The presented methodology involves the integrated usage of experimental and numerical methods to eliminate the difficulties in conducting physical experiments in a wind tunnel. This approach makes it possible to combine the high credibility of experimental data in the study of the physical essence of phenomena with high efficiency and accuracy in determining aerodynamic characteristics by numerical methods. Using this approach, we established dependences of the aerodynamic characteristics of the small-elongation wing configuration with counter-rotating propellers on the geometric and kinematic parameters of the configuration for other extensions and constrictions of the wings. These data can serve as the basis for the development of recommendations for the selection of sensible geometric parameters of the aerodynamic configuration of a small-elongation wing with counter-rotating propellers.

PL

W artykule podjęto problem wyznaczania charakterystyk aerodynamicznych podczas projektowania śmigieł do skrzydeł małych bezzałogowych statków powietrznych (UAV). Omówiono metodykę eksperymentalnych badań nad różnymi konfiguracjami statków ze śmigłami w tunelu aerodynamicznym. Wykazano, że konfiguracje skrzydła o małym wydłużeniu ze śmigłami charakteryzują się brakiem elementów, na które śmigła nie mają wpływu. Cecha ta utrudnia realizację i automatyzację eksperymentów w tunelu aerodynamicznym, powodując problemy z zapewnieniem podobnych warunków do pracy śmigła, trudność w uzyskaniu idealnego wyważenia dla śmigieł z napędem stałym, drgania, których intensywność zależy od niekontrolowanych czynników, niemożność pominięcia obecności elementów nadwozia oddziałujących na łopaty śmigieł oraz trudność bezpośredniego pomiaru ciągu i momentu obrotowego śmigła. Przedstawiona metodyka polega na zintegrowanym wykorzystaniu metod eksperymentalnych i numerycznych w celu wyeliminowania trudności w przeprowadzaniu eksperymentów w tunelu aerodynamicznym. Takie podejście pozwala na połączenie wysokiej wiarygodności danych doświadczalnych w badaniu fizycznej istoty zjawisk z wysoką efektywnością i dokładnością wyznaczania charakterystyk aerodynamicznych metodami numerycznymi. Ustalono zależności charakterystyk aerodynamicznych konfiguracji skrzydła o małym wydłużeniu ze śmigłami przeciwbieżnymi od parametrów geometrycznych i kinematycznych konfiguracji dla innych wydłużeń i zwężeń skrzydeł. Wyniki te mogą stanowić podstawę do opracowania zaleceń dotyczących doboru racjonalnych parametrów geometrycznych konfiguracji aerodynamicznej skrzydła o małym wydłużeniu ze śmigłami przeciwbieżnymi.

5

Analysis of co-flow jet effects on airfoil at moderate Reynolds numbers

Khoshnevis Amir, Yazdani Shima, Saimipour Erfan

Journal of Theoretical and Applied Mechanics

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2020

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Vol. 58 nr 3

685--695

EN

This paper investigates the performance of controlling Co-Flow Jet (CFJ) on NACA 0025 airfoil at five different Reynolds numbers of 5 · 104, 7.5 · 104, 105, 1.5 · 105, and 3 · 105. To conduct the numerical solution of the fluid flow, 2D incompressible and unsteady Reynolds- -averaged Navier-Stokes equations are solved using the SST-k-ω turbulence model. At all investigated Reynolds numbers, the lift coefficient enhances as the momentum coefficient increases, and its best performance is obtained at an angle of attack of (AoA) 15◦. It is also observed that using the CFJ is of greater importance at Re ≤ 105 than in other investigated cases.

6

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.

7

Textile Cover Effect on Aerodynamic Characteristics of a Paraglider Wing

Maślanka Paulina, Korycki Ryszard

Fibres & Textiles in Eastern Europe

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2019

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Vol. 27, no. 1 (133)

78--83

EN

Defined herein are the two PA-fabrics covering a paraglider wing, with the comparative object being permeable clothing material. The material parameters of textiles are applied in numerical simulations of aerodynamic characteristics using the program ANSYS. The state variable is the pressure within the airfoil profile. The space model of a paraglider wing and plane model of its cross-section in the symmetry plane are analysed. The model was approximated by the coordinates of crucial points and smoothed by the spline-curves. The visualisation of stream filaments shows that it is advisable to cover the wing with the impermeable fabric.

PL

W pracy zdefiniowano dwie tkaniny pokrycia skrzydła paralotni wykonane z poliamidu, obiektem porównawczym był przepuszczalny materiał odzieżowy. Parametry materiałowe tekstyliów zastosowano w symulacjach numerycznych charakterystyk aerodynamicznych z wykorzystaniem programu ANSYS. Zmienną stanu było ciśnienie w profilu skrzydła. Analizie poddano przestrzenny model skrzydła paralotni i płaski model jego przekroju poprzecznego płaszczyzną symetrii. Model został przybliżony przez współrzędne punktów węzłowych i wygładzony za pomocą krzywych typu spline. Wizualizacja strug elementarnych pokazała, że celowe jest pokrywanie skrzydła tkaniną nieprzepuszczalną.

8

The influence of ship rolling motion on take-off aerodynamic characteristics of aircraft

He Z., Sun X., Gu X.

Polish Maritime Research

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2018

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S 2

23--29

EN

Ship motion is an important factor affecting on the safety of ski-jump take-off. The simplified frigate ship SFS1 was numerically simulated, and the results were compared with the experimental data, the feasibility of the calculation method was verified; Meshless method and WALE turbulence model were used to simulate the process of aircraft skijump take-off, aerodynamic characteristics under different rolling conditions during the aircraft ski-jump take-off process were presented. The results showed that: the influence of ship rolling motion on lift coefficient, drag coefficient and pitching moment was small, side force and rolling moment were greatly affected by rolling motion; the region of downwash with the maximum speed was about 10 m from the bow; the safety of ski-jump take-off was greatly affected when aircraft was close to the bow within 20 m.

9

Analiza wpływu zastosowania wingletów na charakterystyki aerodynamiczne skrzydła szybowca MDM-1 Fox

Lamach Krzysztof, Szczepaniak Robert, Zahorski Tomasz, Stryczniewicz Wit

Zeszyty Naukowe / Wyższa Szkoła Oficerska Sił Powietrznych

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2017

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Nr 1

139--151

PL

W pracy przedstawiono analizę możliwości wykorzystania metody elementów skończonych do określenia wpływu rozpraszaczy wirów brzegowych (ang. winglet) na charakterystyki aerodynamiczne skrzydła szybowca MDM-1 Fox. Charakterystyki aerodynamiczne są odzwierciedleniem zmieniających się warunków opływu profilu (skrzydła) ze zmianą kąta natarcia. Poprawienie tych charakterystyk na etapie projektowania bądź modernizacji istniejących samolotów skutkuje wzrostem osiągów samolotu, co przekłada się na ekonomię oraz ekologię lotów w przypadku samolotów oraz doskonałość, szczególnie istotną w przypadku szybowców. W pracy przeprowadzono analizę wpływu zastosowania dwóch różnych typów wingletów na osiągi szybowca użytkowanego obecnie bez wingletów. W celu uzyskania wyników porównawczych symulację numerycznej mechaniki płynów wykonano z wykorzystaniem dwóch komercyjnych pakietów obliczeniowych. Uzyskane wyniki potwierdziły poprawność zaproponowanej metodyki.

EN

The authors of the article analyse the possibility of applying the finite element method to determine the impact of winglets on the MDM-1 Fox glider wing aerodynamic characteristic. Aerodynamic characteristics reflect changes in the airflow with the change in the angle of attack. An improvement in these characteristics during the design or modernization stage leads to the increase in the glider performance, which in turn translates into economy and ecology of flight for aircraft as well airworthiness, especially important for gliders. In the paper it was investigated how two different types of winglets affect the performance of the glider in which they are not currently applied. In order to obtain comparative results, simulation of numerical fluid mechanics was performed with the use of two commercial computational packages. The results obtained proved that the method suggested was correct.

10

Wind tunnel tests of quad-rotor autogyro model

Krzysiak A.

Journal of KONES

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2017

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Vol. 24, No. 1

231--238

EN

The wind tunnel investigation of basic aerodynamic characteristics as well as flow visualization tests of the innovative quad-rotor autogyro model is presented. The wind tunnel measurements of aerodynamic characteristics were carried out using 6-component internal strain-gauge balance. In the area of the main rotor and quad-rotors, the flow visualization tests were performed by PIV (Particle Image Velocimetry) System. The work was carried out in cooperation with the Lublin University of Technology, which provided a model of gyroplane manufactured according to their own concept. In the experimental study an influence of quad-rotors as well as pusher propeller on the autogyro model characteristics were determined by measurements aerodynamic forces and moments for a number of selected model configurations. The wind tunnel experimental tests were performed in the Institute of Aviation low speed wind tunnel T-1, characterized by 1.5 m diameter test section. The investigations were carried out for undisturbed flow velocity V∞ = 12.5 m/s, which corresponds to the Reynold’s number, Re = 0.82 * 106 referred to 1 m, The angles of attack used in the experiment were implemented in two ranges -40 ≤ α \ ≤ 20 and 00≤ α ≤ 130, with a sideslip angle β = 0. The tests showed that the flow induced by quad-rotors interfered with the flow induced by the main rotor changing the autogyro aerodynamic characteristics.

11

Ground effect influence on the aerodynamic characteristics of ultralight high-wing aircraft : wind tunnel tests

Placek R., Ruchała P., Stryczniewicz W.

Journal of KONES

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2017

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Vol. 24, No. 2

183--190

EN

The ground proximity may significantly improve the performance of the aircraft, but in some conditions, it affects its stability. The gain of lift which and reduction of drag during low altitude flight is known as the wing in ground effect (WIG effect). It may concern aircrafts or WIG-crafts (ground effect vehicles). In the article experimental results of the wind tunnel test of an aircraft in ground effect has been presented. The main aim of the test was to investigate the ground effect influence on aerodynamic characteristic of the of the ultralight high-wing aircraft model during early take off, taxiing or final landing stage. Investigation was carried out in the 1.5 m diameter low speed T-1 wind tunnel in the Institute of Aviation in Warsaw. The velocity was 32 m/s and Reynolds number related to the aerodynamic chord was equal about 0.37·106. Tests were performed for chosen angles of attack in range 0-10⁰. During investigation, the strain gauge balance measurements and Particle Image Velocimetry (PIV) flow visualization technique were applied. Tested model position was relatively close to the ground. It was found, that the ground proximity has significant influence on the pitching moment. The normal force was increased and the axial force is decreased due to the WIG effect, which is compatible with the theory. It has significant meaning for control aircraft issue and safety.

12

Effects of upstream terrain characteristics on aerodynamic coefficients of structures

Ganapathi C. S., Harikrishna P., Rajan S. S.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 4

776--785

EN

Most research investigations and standards have not emphasized the effects of upstream terrain characteristics on aerodynamic coefficients of structures. Hence in this investigation, pressure measurements study on a 1:2:3 rectangular building model has been simulated through wind tunnel test under uniform, open and suburban terrain condition for 0° and 90° angles of wind incidence. From the variation of pressure and force coefficient values of present study, it is seen that the mean pressure and force coefficient values of all levels of uniform flow condition are on higher side by about 15–40% than the open and suburban terrain values for 0° angles of wind incidence as expected. However the mean pressure and force coefficient values of uniform flow condition are also showed that the values of all levels for 90° angle of wind incidence are on lower side with 20–40% difference than the boundary layer flow values when compared to the values of 0° angle of wind incidence. In addition, the mean pressure and force coefficients of present study has been compared with the Indian and international guidelines to highlight the limitations of codal standards.

13

Numerical Investigation of the Wing-in-Ground Effect on Aerodynamic Characteristics

Wrzesień S., Frant M., Majcher M.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2016

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Vol. 7, Nr 4 (26)

115-130

EN

This paper presents the numerical evaluation of ground (proximity) effects on the basic aerodynamic characteristics of a specifically designed airplane model. The ground effects were investigated in relation to the angle of attack and flight altitude. The results were referenced to the characteristics of an object in motion unaffected by ground effects.

PL

W pracy przedstawiono badania numeryczne wpływu efektu bliskości ziemi na podstawowe charakterystyki aerodynamiczne specjalnie do tego celu zaprojektowanej bryły samolotu. Zbadano wpływ bliskości ziemi w zależności od kąta natarcia oraz w zależności od wysokości lotu. Wyniki odniesiono do charakterystyk obiektu poruszającego się bez efektu bliskości ziemi.

14

Errors and problems while conducting research studies in a wind tunnel -selected examples

Placek R.

Prace Instytutu Lotnictwa

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2016

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Nr 4 (245)

169--177

EN

This paper contains selected examples of errors and problems which can occur while conducting research in a wind tunnel. An inspiration to write this article was struggling with various problems during research experienced by the time period of working in aerodynamic tunnels of the Institute of Aviation . The bulleted list of examples refers to chosen types of research. Every mentioned kind of test is characterised by certain features and an individual approach. The work and methodology problems were the subject of interest. The content, however, does not exhaust the topic, but only reveals some of its aspects. In addition to a short description of selected topics, some actions were indicated,which may help in future research. These suggestions might be useful, especially for novice researchers.

PL

Niniejsza praca zawiera wybrane przykłady błędów oraz problemy badawcze, z jakimi można się spotkać podczas prowadzenia badań w tunelu aerodynamicznym. Inspiracją do napisania niniejszego artykułu było borykanie się z trudnościami i problemami badawczymi w czasie zdobywania doświadczenia podczas wieloletniej pracy w tunelach aerodynamicznych Instytutu Lotnictwa. Wypunktowane w pracy przykłady odnoszą się do różnego rodzaju typu badań. Każde z wymienionych badań jest scharakteryzowane przez określone cechy oraz sposób indywidualnego podejścia. W pracy skupiono się na opisie problematyki prowadzenia oraz metodologii badań. Niniejsza praca nie wyczerpuje tematyki, a jedynie przedstawia jej wybrane aspekty. Oprócz opisania wybranych zagadnień, zasugerowano pewne działania, które mogą być pomocne w przyszłych badaniach. Wymienione wskazówki mogą być użyteczne, szczególnie dla początkujących badaczy.

15

Wind tunnel tests of aircraft aerodynamic characteristics at overcritical angles of attack

Krzysiak A.

Journal of KONES

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2016

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Vol. 23, No. 1

169--176

EN

During air shows or competition aerobatics pilots perform aerobatic flying. Most aerobatic figures are combination of a few basic manoeuvres like loops, rolls, spins, and hammerheads. During such manoeuvres, aerobatic aircrafts often fly in the range of overcritical angles of attack. The flight in the range of higher than critical angles of attack is accompanied by a flow separation. This phenomenon is connected with significant changes of the aircrafts aerodynamic characteristics, as well as may be accompanied by strong vibrations. For these reasons, the knowledge of the aircraft overcritical aerodynamic characteristics is required for its proper design. In wind tunnels models of aircraft are usually tested in the range up to α = 20°-25°, while aircraft performing aerobatic flying usually achieve considerably higher angles of attack. To obtain the aircraft aerodynamic characteristics in the whole used angles of attack range, a special wind tunnel stand was designed and manufactured in the Institute of Aviation enabling the wind tunnel tests in range, α = 0°-360°. The paper presents the wind tunnel tests results of aerobatic aircraft “Harnaś 3” model, for a set of chosen model configurations. The studies included both balance measurements of the model basic aerodynamic characteristic, as well as flow visualization tests. Investigation were carried out for the range of angles of attack α = -90°-90° and the range of slideslipe angles β = -90°-90°. Wind tunnel tests are very rarely carried out in such a wide angles of attack range. The experimental tests were performed in the Institute of Aviation‘s low speed wind tunnel T-1 (1.5 meter diameter test section). For the tests, the model of aerobatic aircraft (manufactured in a 1:10 scale) was situated both vertically and horizontally in the wind tunnel test section. Wind tunnel tests were performed at Mach number M ≈ 0.1 (V ≅ 34 m/s), which corresponds to the Reynolds number Re = 0.22*106.

16

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.

17

Charakterystyka aerodynamiczna wybranej nasady kominowej stosowanej na przewodach wentylacji grawitacyjnej

Gnatowska R.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

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2015

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T. 46, nr 6

231--234

PL

Tematem artykułu jest analiza charakterystyk aerodynamicznych wybranych oraz dostępnych na rynku nasad kominowych, które stosowane są na przewodach wentylacji grawitacyjnej. Podstawowym zadaniem tych nasad jest wspomaganie ciągu kominowego (zabezpieczenie przed odwrotnym przepływem powietrza i zwiększenie strumienia powietrza wywiewanego z pomieszczenia) oraz ochrona przed zawiewaniem. W budynkach, które wentylowane są w sposób naturalny, zanieczyszczone powietrze usuwane jest przez kanały wentylacyjne, których skuteczność zależy od siły ciągu zależnego od wielu czynników. Pomiar charakterystyk aerodynamicznych wykonano według normy PN-EN 13141-5 - „Wentylacja budynków. Badanie właściwości elementów/wyrobów do wentylacji mieszkań. Część 5: Nasady kominowe i wyrzutnie dachowe”. Badania obejmowały między innymi wpływ kierunku wiatru na działanie ssące. Wnioski podane w artykule umożliwiają dobór odpowiedniej nasady, a także ocenę jej efektywności usuwania powietrza przez badaną nasadę kominową.

EN

Chimney cowls are devices designed to assist building ventilation system with the use of wind power. They operate on the principle of generating negative pressure, whereby air inside the building is transported outside. The aim of article is to analyze the aerodynamic characteristics of the selected and available chimney cowl used in the process of natural ventilation. Furthermore, the article also demonstrated some general qualities of chimney cowls, which basic function is support the stack effect (preventing inversed air flow) and protect from inflow of fresh air from the outside. The article's measurement was regulated by the standard PN-EN 13141-5 „Ventilation for buildings - Performance testing of components/products for residential ventilation - Part 5: Cowls and roof outlet terminal devices". The obtained results of the research support proper choice of a chimney cowl. In addition, they can be also applied in estimation of effectiveness of agent's extraction by the mentioned cowl.

18

Modelowanie parametrów aerodynamicznych urządzeń energetyki wiatrowej II. Analiza aerodynamiczna turbin wiatrowych o poziomej osi obrotu

Sorko S. A., Teleszewski T. J.

Symulacja w Badaniach i Rozwoju

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2014

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Vol. 5, nr 1

57--69

PL

Przedmiotem opracowania jest metoda obliczeniowa wyznaczania przepływu przez wirniki niewielkich osiowych turbin wiatrowych o gęstych palisadach łopatkowych i wyznaczania charakterystyk aerodynamicznych tych urządzeń. Przedstawiono algorytm obliczeniowy oparty na koncepcji podziału wirnika osiowego na wirniki elementarne i konforemnym odwzorowaniu kołowych palisad profili na osiowosymetrycznych powierzchniach prądu na płaskie palisady profili, w których opływ palisady i charakterystyki aerodynamiczne są wyznaczane metodą hydrodynamicznych osobliwości.

EN

An object of the elaboration is the computational method solution of the flow through rotors of small axial wind turbines and calculations of aerodynamic characteristics of these devices. One presented the computational algorithm based on the idea of the partition of the axial rotor on elementary rotors and the conformal mapping of aerofoil cascades on axis-symmetrical surfaces on flat straight cascades in which flow through the cascade and it aerodynamic characteristics are calculated by the method of hydrodynamic singularities.

19

Experimental Research of Tandem-Scheme UAV Model Aerodynamic Characteristics

Masko O. M., Kryvokhatko I. S., Sukhov V. V.

Prace Instytutu Lotnictwa

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2014

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Nr 4 (237) December 2014

63--75

EN

Tandem-wing aerodynamic scheme became widespread for tube launch UAV due to possibility of required flight performance realization under tight dimension constraints. In this work results of wind tunnel weight and visual tests of UAV model with wingspans about 1 m are presented. Model aerodynamic characteristics were defined by six-component wind tunnel balance at Mach number 0.075 and Reynolds number 187 000 calculated for one wing chord of 0.11 m. Model stagger (390, 490, 590 mm), rear wing dihedral angle (0°, -5°, -9°), forward-to-rear wingspan ratio (0.67; 0.9; 0.92; 1.24) were variable. It was determined that model is longitudinal and directional static stable, has high maximal lift-drag ratio (in range from 10.6 to 13.7) and acceptable maximal lift coefficient without flaps (from 1.05 to 1.09) and critical angle of attack (from 15.1 to 16.4°). Stagger increasing leads to zero or positive maximal lift-drag ratio increasing. If forward wing span is larger than rear wing span than stagger increasing is more effective with zero dihedral angle. If rear wing span is larger than forward wing span than stagger increasing is more effective with negative dihedral angle.

20

Analiza wpływu parametrów geometrycznych skrzydła na jego charakterystyki aerodynamiczne z wykorzystaniem modeli numerycznych

Kołodziejczyk R., Lichoń D.

Logistyka

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2014

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nr 6

5582-5591

PL

W pracy przedstawiono praktyczne wykorzystanie metody panelowej VLM do wyznaczania charakterystyk aerodynamicznych skrzydła jak również rozkładu siły nośnej czy współczynników oporu po rozpiętości tego skrzydła. Metoda panelowa jest metodą stosunkowo prostą dającą zadowalające wyniki. Zasady obliczeń oraz struktura metody panelowej zostały po krótce przedstawione w niniejszej pracy. Na podstawie przeprowadzonych obliczeń oraz analizy otrzymanych wyników widać jak parametry geometryczne skrzydła wpływają na wyżej wspomniane charakterystyki. Znajomość tego wpływu geometrii na współczynniki siły nośnej, oporu, momentu pochylającego itd. jest bardzo istotna z punktu widzenia konstruktora obiektów latających, ponieważ daje możliwość świadomego kształtowania skrzydła w celu uzyskania oczekiwanych rezultatów. Przedstawione w pracy wyniki pokazują, że wykorzystanie metod numerycznych pozwala na badanie zagadnień bardzo złożonych a zarazem jest oszczędnością czasu dla konstruktora.

EN

The paper presents a practical use of the Vortex Lattice Method (VLM) to determine the aerodynamic characteristics of the wings as well as the distribution of lift and drag coefficients along the span of the wing. VLM is a relatively simple method which gives satisfactory results. Calculation rules and the structure of the method are briefly presented in this paper. On the basis of calculations and analysis of the results it can be seen how the geometric parameters of the wings affect the above-mentioned characteristics. Knowledge of the effect of geometry on the coefficients of lift, drag, pitching moment and so on is very important from the point of view of the constructor of flying objects because it gives the opportunity to shape the wing intentionally in order to obtain the expected results. The work results show that the use of numerical methods allows the study of very complex problems and is also a labour saving for constructor.