Wyniki wyszukiwania - BazTech

1

Experimental and CFD study of the selected acoustic helicoidal resonator as a final element of an air installation

Łapka Wojciech, Jakubowski Piotr

Vibrations in Physical Systems

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2023

|

Vol. 34, nr 1

art. no. 2023112

EN

The work presents an analysis of the selected helicoidal resonator as the end element of the air installation. Laboratory tests of the acoustic pressure level were performed at the outlet of the air installation in a room for different flow speeds. The measurement methodology in accordance to standards PN-EN ISO 3741 and PN-EN ISO 5135, which describes the acoustic test facilities, instrumentation and procedures to be used for precision grade determination of sound power levels in octave or one-third-octave bands of a noise source in reverberation test rooms. The numerical CFD tests show the shape of the air stream in the function of the distance from the installation outlet for different flow speeds. Due to the helicoidal shape of the analyzed acoustic helicoidal resonator, the air stream also turns, which can be used to effectively mix air in the room.

2

Experimental tests of laminated glass with embedded steel mesh subjected to in-plane loading

Kozłowski Marcin, Wasik Dominik

Architecture Civil Engineering Environment

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2023

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Vol. 16, no. 3

77--88

EN

This article presents the issue of the in-plane post-breakage capacity of laminated glass elements. It presents the results of an ongoing research project that aims to develop novel reinforced, laminated glass elements with embedded steel woven mesh and increased post-breakage capacity. The research was focused on tensile strength tests in a custom-made experimental set-up. The tests were carried out on laminated glass samples consisting of two glass panes with 8, 10 and 12 mm thicknesses, bonded with an EVA Clear interlayer (3.04 mm thick). A total of 36 reference and reinforced samples were tested (6 series of 6 samples each). During the tests, an increase in load after glass breakage was observed for all samples, however, the samples reinforced with steel mesh showed much better strength in the post-breakage phase. It was found that the steel woven mesh embedded in laminated glass increases the post-breakage capacity by approximately 300% compared to the reference samples.

3

Planowane krajowe laboratorium badawcze sieci i usług 5G wraz z otoczeniem

Burakowski Wojciech, Bęben Andrzej, Sosnowski Maciej, Więcek Dariusz, Michalski Igor, Woźniak Józef, Gierłowski Krzysztof, Hoeft Michał, Schauer Patryk, Warzyński Arkadiusz, Natkaniec Marek, Boryło Piotr, Binczewski Artur, Belter Bartosz, Furmann Maksymilian

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2022

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nr 4

110--115

PL

Przedstawiono koncepcję infrastruktury PL-5G pt. Krajowe laboratorium sieci i usług 5G wraz z otoczeniem. Laboratorium to będzie ważną infrastrukturą badawczą w kraju, która powinna w istotny sposób przyczynić się do ukierunkowania praktycznych badań dotyczących nowych generacji dla infrastruktur sieciowo-obliczeniowych Internetu. Laboratorium to będzie zlokalizowane w czterech miastach, tj. w Gdańsku, Krakowie, Poznaniu i Wrocławiu i będzie miało wspólny system sterowania eksperymentami. Korzystanie z laboratorium będzie zdalne, co umożliwi zespołom krajowym z innych lokalizacji efektywne korzystanie z jego zasobów. Przewiduje się, że będzie również wykorzystywane w procesie dydaktycznym realizowanym przez uczelnie techniczne. Termin zakończenia budowy laboratorium przewiduje się na koniec 2023 r.

EN

The paper describes concept of PL-5G infrastructure entitled: National laboratory of 5G networks and services jointly with measurement tools and applications. The laboratory will be important element for improving research on new generation infrastructure for the Internet. It will be located in 4 cities, i.e. in Gdańsk, Kraków, Poznań and Wrocław. Common control system will manage all running experiments. Access to the laboratory will be remote to allow all researchers from Poland for effective usage of resources. The laboratory will be also usable for improving didactic process in technical universities. The laboratory will be open at the end of 2023.

4

Prediction of ship motions in irregular waves based on response amplitude operators evaluated experimentally in noise waves

Bielicki Sebastian

Polish Maritime Research

|

2021

|

nr 1

16--27

EN

The most common methods for predicting ship roll motions in a specified sea state are direct measurements of motions in a representative irregular wave realisation (time domain) or calculations of motions from response amplitude operators (RAOs) in the frequency domain. The result of the first method is valid only for the tested sea state, whilst the second method is more flexible but less accurate. RAO-based predictions are calculated assuming a linear model of ship motions in waves. RAO functions are usually evaluated by means of tests in regular waves for a limited number of frequencies and a constant wave amplitude. This approach is time-consuming and the discrete form of the RAO functions obtained for a limited number of frequencies may lead to discrepancies in the prediction of seakeeping and often does not allow the actual amplitude of the response in resonant frequency to be determined. Another challenge is the appropriate selection of wave amplitude for tests due to the considerable influence of viscous damping on roll response in irregular sea waves. There are alternative methods for the experimental determination of RAO functions and one of them is presented in this study. The presented approach allows RAO functions to be evaluated in one run by the generation of irregular waves characterised by a white or coloured noise spectrum. This method reduces the experiment duration, with almost continuous RAO characteristics obtained. The flat (white noise) and linear (coloured noise) wave spectral energy characteristics are considered in the experiment and the obtained predictions are compared with the results of accurate measurements in irregular waves.

5

Experimental assessment of thermal, humidity and flow conditions in the indoor swimming pool

Ciuman Piotr

Instal

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2020

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nr 4

32--38

EN

Indoor swimming pools belong to ventilated facilities in which due to the complex nature of air, heat and moisture flow there are difficulties in shaping the conditions of the indoor environment, suitable for the occupants. The aim of the presented research was to assess the thermal, humidity and flow conditions in the actual ventilated school swimming pool. The assessment was carried out based on long-term and short-term measurements of indoor air parameters: temperature, relative humidity and speed, which were carried out over different periods of the year. Comparing the results of the research with the air parameters recommended for indoor swimming pools in the literature sources, the need to improve thermal, humidity and flow conditions in the facility by modernizing the ventilation system was indicated.

PL

Hale pływalni należą do obiektów wentylowanych, w których ze względu na złożony charakter przepływu powietrza, ciepła i wilgoci występują trudności w kształtowaniu warunków środowiska wewnętrznego, odpowiedniego dla przebywających ludzi. Celem prezentowanych badań była ocena warunków cieplno-wilgotnościowych i przepływowych w rzeczywistej wentylowanej szkolnej hali pływalni. Została ona przeprowadzona na podstawie ciągłych i krótkotrwałych pomiarów parametrów powietrza wewnętrznego: temperatury, wilgotności względnej i szybkości, które wykonano w różnych okresach roku. Porównując wyniki badań z wartościami parametrów zalecanymi dla pływalni w źródłach literaturowych, wskazano na potrzebę poprawy warunków cieplno-wilgotnościowych i przepływowych w obiekcie przez modernizację instalacji wentylacyjnej.

6

Parameter identification of Bouc-Wen model for vacuum packed particles based on genetic algorithm

Bartkowski Piotr, Zalewski Robert, Chodkiewicz Paweł

Archives of Civil and Mechanical Engineering

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2019

|

Vol. 19, no. 2

322--333

EN

This paper investigates cylindrical samples made of vacuum packed particles. Such structures are composed of granular media placed in a hermetic encapsulation where, in the final stage, a partial vacuum is generated. The main advantage of such a structure is that the underpressure value makes it possible to control the global physical properties of granular systems. Materials with various grains are analyzed in the paper. A modified Bouc-Wen hysteresis model is adopted to describe the nonlinear properties of the tested specimens. To identify the model parameters, a genetic algorithm is applied. The proposed model is found to be in good agreement with the experimental data.

7

Analysis of the influence of magnetic induction ramp profile on axial force and friction torque generated by MR fluid

Horak Wojciech, Szczęch Marcin

Acta Mechanica et Automatica

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2019

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Vol. 13, no. 3

153--157

EN

The unique properties of magnetic fluids result from their ability to undergo reversible, almost immediate, changes in their rheological properties under the influence of magnetic fields as well as the possibility to position them by magnetic field forces. It is also possible to control the direction and flow rate of such fluids. These properties provide an efficient way to develop new types of controllable machines and devices, such as brakes, clutches and bearings. The objective of the study was to examine the axial force and torque friction of a magnetorheological (MR) fluid working in the shear flow mode (parallel plate system) subjected to different magnetic induction ramp profiles. The rotation speed and working gap height were also taken into account. Determining the response of the tested system to magnetic induction change in different working conditions was of particular interest.

8

Zanim powstała centrala początki telefonii w Krakowie w świetle materiałów prasowych

Więcek M.

Maszyny Elektryczne : zeszyty problemowe

|

2018

|

Nr 4 (120)

209--216

PL

Pierwsze próby z wykorzystaniem telefonów zostały przeprowadzone w Krakowie pod koniec 1877 roku. Szeroka publiczność miała okazję zetknąć się z tym wynalazkiem za sprawą publicznych prezentacji, organizowanych przez takich wynalazców jak Henryk Machalski lub Emil Protaszewicz. Na początku lat 1880-tych telefonia zaczęła zyskiwać znaczenie jako praktyczny środek wewnątrz budynków. Pierwsza próba organizowania publicznej sieci telefonicznej została podjęta pod koniec 1882 roku przez prywatne przedsiębiorstwo i po kilku latach zakończyła się niepowodzeniem. W roku 1887 udało się natomiast uruchomić miejską sieć przeciwpożarową, w której zastosowanie znalazło kilkanaście aparatów telefonicznych. W tym samym roku wznowiono działania zmierzające do uruchomienia w Krakowie publicznej sieci telefonicznej, tym razem pod auspicjami państwa. Projekt został jednak opóźniony, przez co faktyczne prace budowlane rozpoczęto dopiero w roku 1892. Sieć rozpoczęła działanie jeszcze przed oficjalnym uruchomieniem, w dniu 1 stycznia 1893 roku.

EN

First experiments with telephones in Cracow were conducted at the end of the year 1877. Wide audience had an opportunity to see the new invention during public presentations, organized by such inventors as Henryk Machalski or Emil Protaszewicz. During early 1880s telephony gained popularity as means of communication inside of buildings. First failed attempt to create public telephone network in the city was was made in 1882, by private enterprise. In 1887 city-wide fire protection network was established, utilizing both telephone and telegraph devices. In the same year goal of creating public telephone exchange system was resumed by the State. Due to delays first construction works were performed in 1892. Network was operational before its official launch on January 1, 1893.

9

Advances in Fundamental Studies on Partially Filled Tribological Gaps

Mueller M., Ostermeyer G. P.

Machine Dynamics Research

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2018

|

Vol. 42, No. 3

5--15

EN

Tribological scenarios with partially ﬁlled gaps can occur when either a lubricated system runs under starved lubrication or a system that usually operates under dry conditions is wetted by a ﬂuid. In order to get a detailed insight into the tribological character of partially ﬁlled gaps, it is necessary to investigate the dynamics of the ﬂuid ﬂow and its interaction with the pressure, velocity, nominal gap height and deformations. Within this problem, the total amount of ﬂuid in the gap plays a crucial role. Recent studies with novel models have shown that particularly near the fully ﬁlled regime the built up pressure is highly dependent on the ﬁlling ratio. Further studies proved that the ﬂuid forms characteristic bow waves in front of asperities thus leading to larger mean pressure values in the contact. This paper extends these ﬁndings by experimental investigations on different length scales. Special focus is on the correlation between the friction coefﬁcient and the supplied ﬂuid volume.

10

The use of Vacuum Packed Particles with adaptable properties in acoustic applications

Zalewski R., Rutkowski M.

Journal of Theoretical and Applied Mechanics

|

2018

|

Vol. 56 nr 2

403--416

EN

The aim of this paper is to present possibilities of using a new type of granular media in acoustics as innovative sound absorbers. Most materials of this type have a porous or fibrous structure. It is constant, and once manufactured, does not easily change its configuration. The examined material – Vacuum Packed Particles (VPP) is of a changeable structure. It can be assumed that the acoustical absorption of such structures can be modified and partially adjusted by an external factor. First steps in an experimental approach have been made – the acquired results are optimistic. Additional tests are being planned to confirm the observed phenomenon and to apply VPP as novel materials in acoustics. Basing on the preliminary experimental tests, it can be concluded that the considered structures could become a significant part of a multilayered structure which would have controllable sound absorption properties.

11

Małe turbiny parowe dla energetyki rozproszonej– uwarunkowania techniczno-ekonomiczne

Kryłłowicz W., Kantyka K.

Rynek Energii

|

2017

|

Nr 6

41--46

PL

Artykuł dotyczy zagadnienia możliwości i opłacalności produkcji w kraju małych turbin dla energetyki rozproszonej. Opisane są dwie zrealizowane konstrukcje małych turbin parowych o mocach 50 i 165 kW (odpowiednio turbina kondensacyjna i turbina przeciwprężna). Ponadto omówiono wyniki badań prowadzonych na stoisku turbiny modelowej TM1 -3, a dotyczących charakterystyk zewnętrznych stopni modelowych małych turbin akcyjnych dla różnych wariantów konstrukcyjnych: koła wirnikowe z bandażami lub bez. Przeprowadzono uproszczoną analizę kosztów produkcji turbin w zależności od mocy na wale (w zakresie do 250 kW). Poruszono zagadnienie cen i dostępności armatury dla turbin małej mocy.

EN

A possibility and cost-effectiveness of producing small turbines for distributed power generation is discussed. Designs of two small steam turbines with power ratings of 50 and 165 kW (a condensing turbine and a back pressure turbine, respectively) are described. In addition, the results of experimental investigations conducted on the TM1-3 model turbine stand, concerning the external characteristics of the model stages of small turbines for different design variants impellers with or without bandages are presented. A simplified analysis of turbine production costs depending on the shaft power (up to 250 kW) has been conducted. An issue of prices and availability of control valves for low power turbines is discussed.

12

150-lecie urodzin Marii Skłodowskiej-Curie, dwukrotnej laureatki Nagrody Nobla (w 1903 i 1911 r.)

Rurarz E., Sobieszczak-Marciniak M.

Postępy Techniki Jądrowej

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2017

|

z. 3

30--39

PL

Rok 2017 jest czasem wielu rocznic związanych z Marią Skłodowską-Curie i jej dokonaniami. 150 rocznica urodzin uczonej, 120 rocznica urodzin Ireny Joliot-Curie, 10 rocznica śmierci Ewy Curie Labouisse i 85 rocznica otwarcia Instytutu Radowego w Warszawie to przyczynek do wielu wydarzeń i artykułów na temat życia, odkryć i osiągnięć Marii Skłodowskiej-Curie. Historia badań nad promieniotwórczością, pierwiastkami promieniotwórczymi, to historia fizyki jądrowej, chemii radiacyjnej i onkologii. Oczywiście Maria i Piotr Curie nie byli jedynymi uczonymi zajmującymi się tymi dziedzinami, ale niewątpliwie to właśnie oni, a właściwie Maria Skłodowska-Curie była inicjatorką tak nowoczesnego myślenia o atomie. To dzięki jej uporowi, odwadze w stawianiu pytań i wydawałoby się niemożliwych do udowodnienia hipotez, nauka zawdzięcza nowe metody badawcze i pierwiastki promieniotwórcze. To jej kompleksowe myślenie o badaniach naukowych i medycynie dało początek nowoczesnym metodom leczenia nowotworów, powstanie dwóch bliźniaczych placówek onkologicznych- Instytutów Radowych w Paryżu i w Warszawie otworzyło drogę do budowy całej sieci onkologicznej i kompleksowego leczenia pacjentów.

EN

Year 2017 is a year of many anniversaries connected with Maria Skłodowska-Curie and her achievements. The 150th anniversary of the birth of Maria Skłodowska-Curie, the 120th anniversary of the birth of Irena Joliot-Curie’s, the 10th anniversary of Eve Curie Labouisse’s death and the 85th anniversary of the opening of the Radium Institute in Warsaw represent a contribution to many events and articles on Maria Skłodowska-Curie’s life, discoveries and accomplishments. The history of research on radioactivity and radioactive elements is the history of nuclear physics, radiation chemistry and oncology. Obviously, Maria and Piotr Curie were not the only scientists involved in these fields, but undoubtedly they, or Maria Skłodowska-Curie actually, who initiated such modern thinking about the atom. It is thanks to her persistence and courage to ask questions, as well as her perseverance in proving hypotheses that had been almost impossible to prove, the science owes new research methods and radioactive elements. It is Maria Curie’s comprehensive thinking about the research and medicine that has given rise to modern methods of cancer treatment, the establishment of two twin oncology centres: the Radium Institute in Paris and in Warsaw. These have opened the way to building the entire oncology network and comprehensive patient treatment.

13

Identification of the characteristics of a carbon dioxide breathing rotary sliding-vane expander

Milewski J., Lis P., Olszewski A., Sieńko A., Sęk T.

Journal of Power Technologies

|

2017

|

Vol. 97, nr 3

259--264

EN

This paper presents a study providing the experimental analyses on the rotary vane expander operating conditions with carbon dioxide as working fluid in comparison against air (chosen as reference). Such working fluid is promising for application as energy converters in a waste heat recovery for electric power. Experiments were performed on a prototype of rotary sliding vane expander. The experiment demonstrated that commercially available multi–vane pneumatic engines can be adopted to waste heat recovery systems. During the experiments, the operation of the multi–vane expander was kept under observation for various inlet temperature, various pressure ratios, and various rotational speeds. Adequate maps of performances for air and carbon dioxide were created, compared against each other, and commented. In general, by using the same machine, power and efficiency can be raised by only change of working fluid.

14

Modelling and Experimental Testing of Hybrid Joints Made of: Aluminium Adherends, Adhesive Layers and Rivets for Aerospace Applications

Sadowski T., Golewski P.

Archives of Metallurgy and Materials

|

2017

|

Vol. 62, iss. 3

1577--1583

EN

The contemporary demands in different branches of engineering require application of new multi-component materials and structural systems. Appropriately chosen joining technology can offer significant enhancement of structural system performance in terms of effectiveness, reliability, safety and other design criteria. The modern applications of complex joints are of great technological interest as they permit to combine and to enhance the individual effects of each kind of joint. This is of great importance for modern applications in different branches of engineering: aerospace, mechanical and civil. Therefore in this paper we will focus on the analysis of mechanical response of adhesive joint of aluminium strips reinforced by rivets. The aim of the paper is to investigate experimentally the mechanical behaviour of adhesive joint of aluminium strips reinforced by rivets for industrial applications in aerospace. The considered joint was subjected to uniaxial loading. The tests in this paper were performed for: • classical adhesive joint in order to investigate material parameters for numerical modelling of the hybrid joint • hybrid joining of the structural elements in order to investigate the reinforcement effect. The experiments with application of digital image ARAMIS system allowed for on-line monitoring of the deformation process of the considered joining elements. The particular distributions of displacement fields at the joint surface were estimated for any stage of loading process. Numerical modelling was performed for experimentally investigated specimens. The materials parameters, necessary for calculation, were estimated from experiments. FEA modelling was done with the help of ABAQUS code.

15

On the violin bridge hill – comparison of experimental testing and FEM

Jansson E. V., Barczewski R., Kabała A.

Vibrations in Physical Systems

|

2016

|

Vol. 27

151--160

EN

Italian violins of the golden era and French violins are different. Measurements of bridge mobility show that the Italian violins have a local maximum (a hump) at approx. 2,5 kHz in the bridge mobility. The French violins do not show this maximum. The arching along the centre line is different. The Italian violins are flat between the f-holes while the French ones are arched. Does this difference in design explain the difference in bridge mobility and tone? Proposed FEM simulation and digital signal post-processing of the time series are promising methods of the virtual testing of various violin models. These techniques may give an answer for the question above and they should be helpful in achieving high tonal quality of violin.

16

Ocena działania perfogeneratora w warunkach otworopodobnych – testy strzałowe

Habera Ł., Frodyma A., Godzik E., Koślik P., Hadzik J., Wilk Z.

Prace Naukowe Instytutu Nafty i Gazu

|

2016

|

nr 209 wyd. konferencyjne

663--666

PL

Artykuł poświęcony jest ocenie zdolności zainicjowania perfogeneratora prochowego uzbrojonego w paliwo obciążone materiałem podsadzkowym w postaci piasku kwarcowego. Istotą badań było przeprowadzenie serii eksperymentów strzałowych z wykorzystaniem wytłoczonych segmentów paliwowych ze zmienną zawartością piasku kwarcowego. W tym celu przygotowano stanowiska betonowe na poligonie, wykonano fragmenty odcinka perfogeneratora, zaprasowano pierścienie paliwowe ze zmienną ilością propantu oraz przeprowadzono badania strzałowe na tychże modelach. Ocenie poddano fakt samej inicjacji paliwa oraz wielkość i charakter spękań wywołanych spaleniem paliwa w atrapie otworu wiertniczego.

EN

Shooting experiments on a fire-ground constituted the main part of the research. In order to strengthen the effect of fracture propping, the research team has developed a method of joining the propellants with proppants in single, monolithic form, which shall enable to perform the gas fracturing jobs with immediate release of the proppants. The research involved selecting an appropriate proppant material, constructing experimental models and performing a number of fire-ground shooting experiments with use of proppant-loaded propellant materials.

17

Test Stand for Investigations of Magnetorheological Elastomers

Skalski P.

Machine Dynamics Research

|

2016

|

Vol. 40, No. 4

51--57

EN

The new experimental test setup for investigations of magnetorheological elastomers was conceived and constructed in the Institute of Aviation. The goal of this paper is to present the test stand, which makes determining the magnetic parameters of magnetorheological elastomers. The magnetic hysteresis curve of the magnetorheological elastomer fabricated with the carbon iron particles dispersed in natural rubber was studied in the magnetic field. The principle of operation, and results from experiment were presented.

18

Aviation Structure With a Magnetorheological Elastomer

Skalski P.

Machine Dynamics Research

|

2016

|

Vol. 40, No. 3

123--130

EN

In the paper the application of a magnetorheological elastomer (MRE) in an aviation structure was presented. The prototype of the aviation structure with MRE was described. The original, carbon composite model set a reference value of both lift and drag coefficients for an E214 profile. Experiments were conducted in order to evaluate the influence of the magnetorheological elastomer (placed on a surface of a wing) on the overall performance. Results of experiments were depicted and discussed.

19

Semi-active linear vacuum packed particles damper

Zalewski R., Chodkiewicz P.

Journal of Theoretical and Applied Mechanics

|

2016

|

Vol. 54 nr 1

311--316

EN

In this paper, the authors focus on the proposition of an innovative semi-active linear damper prototype working on the basis of granular materials. Vacuum Packed Particles (VPP) belong to the class of materials whose mechanical (rheological, dissipative) properties may be quickly changed by applying a partial vacuum inside the system. The concept of an innovative linear damper based on VPP is presented in the paper. Typical experimental results are presented to reveal changeable damping characteristics of the device. Additionally, the mathematical model is proposed to capture extraordinary features of the investigated damper.

20

Application of a magnetorheological elastomer in an aviation structure

Skalski P.

Journal of KONES

|

2016

|

Vol. 23, No. 3

449--455

EN

Magnetorheological elastomers have properties that can be altered by magnetic field. Many materials were invented more than 30 years ago, but their development and improvement over the past three decades has led to new, more varied uses of these adaptable materials. The main goal of the paper is to present and investigate the application of a magnetorheological elastomer in an aviation structure. The potential advantage of this solution is a possibility to adjust the shape of the wing during the flight by altering the magnetic field strength, which in turn causes deflection of a magnetorheological elastomer. For the purpose of the investigations, an E214 aerofoil has been selected. The original, carbon composite model set a reference value of both lift and drag coefficient for an E214 profile. A thin layer of magnetorheological elastomer was placed on the upper side of the reversed wing. In order to fully understand the effect of such structural change on an aerial profile, the new research stand was designed and manufactured for the purpose of this research in the Institute of Aviation. Experiments were conducted due to evaluate the influence of magnetorheological elastomer on the overall performance. Results of investigations were presented and discussed.