Wyniki wyszukiwania - BazTech

1

Flight of a Guided Aerial Bomb Along a Vertical Plane in Turbulent Atmosphere

Stefański Konrad, Grzyb Marta

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2019

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Vol. 10, Nr 3 (37)

19--30

EN

The control of a homing flying object, which a guided aerial bomb (GAB) is, takes place in the earth’s atmosphere, which may feature various atmospheric phenomena that are disturbances to the GAB control. The atmospheric disturbances include air turbulences, wind pockets, and wind gusts. For the purpose of the research discussed in this paper, the atmospheric disturbances were qualified as a stochastic process of power spectral density according to the Dryden model. This paper presents a method of controlling a GAB in motion through a turbulent atmosphere of the earth. The GAB was homed to a moving ground target by the most universal method of proportional navigation. The research discussed in this paper included an analysis of the effect of atmospheric disturbances on the target striking accuracy of a GAB moving along a vertical plane, the GAB flight trajectory, the values of force inputs which controlled the GAB flight, the values of actual attack angles, the values of kinematic transverse overloads, and the control errors input to the guidance controller. The numerical simulations were completed during the research in Matlab/Simulink, and certain results thereof are represented in a graphical format.

PL

Proces sterowania samonaprowadzającym się obiektem latającym jakim jest lotnicza bomba kierowana (LBK) odbywa się w atmosferze ziemskiej, w której zachodzą różnego rodzaju zjawiska atmosferyczne będące zakłóceniami. Takimi zjawiskami mogą być na przykład: turbulencje, uskoki wiatru, jak też jego podmuchy. Dla potrzeb badań zakłócenia takie przyjęte zostały jako proces stochastyczny w postaci gęstości widmowej mocy to znaczy według modelu Drydena. W niniejszej pracy zaprezentowano metodę sterowania lotniczą bombą kierowaną, która porusza się w ziemskiej atmosferze zaburzonej. Do naprowadzania tego obiektu latającego na poruszający się cel naziemny wykorzystana tu została, jako najbardziej uniwersalna, metoda proporcjonalnej nawigacji. Przeprowadzone w pracy badania objęły analizę wpływu zakłóceń atmosferycznych na dokładność trafienia w cel przez poruszającą się w płaszczyźnie pionowej bombę kierowaną, kształt toru jej lotu, wartości generowanych sił sterujących lotem LBK, wartości realizowanych kątów natarcia, wartości kinematycznych przeciążeń poprzecznych, jak również uchybów sterowania podawanych na regulator. Symulacje numeryczne przeprowadzone zostały w środowisku Matlab/Simulink, a niektóre wyniki badań przedstawione są w postaci graficznej.

2

Renormalised group methods for theoretical description of a turbulent fluid motion

Klopkov Y., Zharov V., Gusarova K.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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2001

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nr 11

129-134

EN

A number of monographies and scientific papers are devoted to the problem of theoretical description of turbulent phenomena as this problem has appeared to be unfading for more than 150 years. From time to time there arise very bright new ideas and methods, which inspire many scientists to overcome unusual difficulties connected with understanding of the essence of the problem. Nevertheless the practical importance of an engineering solution to this problem has generated a great number of semiempirical models where the question about essence of the problem is not considered and the results are adjusted to a certain set of practically important flows. Thus the emphasis is put on the description of low order average such as average velocity, average pressure, average kinetic energy, average concentration of chemical components etc. Besides modeling has been developed due to impossibility of direct numerical simulation of flows at very high Reynolds numbers. Nevertheless significant progress in experimental and theoretical studies of non-isotropic turbulent flows has been recently made. It enables us to turn to the original problems connected with the essence of the phenomenon [1-4].

3

Comparison between 2D and 3D supersonic shear layer calculations using les method

Iourokina I.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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2001

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nr 11

111-118

EN

A numerical method for a direct simulation of the large-scale turbulence is proposed based on the Smagorinsky model of subgrid-scale turbulence. 2D and 3D numerical modeling of supersonic shear layer using the given method at the Alpha XL 266 workstation is presented. Numerical and experimental results are compared and an analysis of this comparison is given as well. A special attention is paid to a significant difference between 2D and 3D calculations and the reason for this difference is discussed. The possibility of using a personal computer in such calculations is investigated. In particular, the processing time and virtual memory used are estimated for each calculation.

4

Laminar-turbulent transition of the incompressible swept attachment-line

Wrona M., Tuliszka-Sznitko E.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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2000

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nr 10

219-224

EN

The linear and non-linear stability analyses of an incompressible attachment-line flow is presented within the temporal and special frameworks. The analyses are carried out in the cases with blowing and suction. The theory of stability equations is solved using the spectral collocation method.

5

An experience of using the method of direct numerical simulation of large-scale turbulence to the computation of supersonic turbulent shear layer

Tixtinskaya J.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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1999

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nr 9

213-219

EN

One of the modification of Large Eddy Simulation method is developed. It is applied to the problem of mixing of two supersonic flows. Kelvin-Helmholtz instability is obtained. Instantaneous data are averaged and the shear layer thickness is calculated. It is compared with the experimental one. The conclusion about the sensitivity of the method to the change in model constants is made.