Wyniki wyszukiwania - BazTech

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Simulation modeling of random change of ground surface characteristic during military tracked vehicle motion

Rudiy A., Khaustov D., Bystrytsky M.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 1

137--146

EN

This article is dedicated to the study of the simulation modeling of random external perturbation influence on the military tracked vehicles motion, including accidental changes of the ground surface characteristics. Despite the significant amount of work done on the subject, the modeling of the ground surface characteristics changes needs additional consideration. Based on the inverse-transform method, this article proposes an algorithm to obtain an array of random coefficients of resistance to the linear motion and rotation. The results show that the algorithm can improve the accuracy of the simulation of tracked military vehicles perturbed motion and could be useful for studies aimed at improving the transmission elements and power units of military tracked vehicles.

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Metodyka numerycznego wyznaczania współczynników oporu nadwodnej części statku

Kaup J.

Zeszyty Naukowe / Akademia Morska w Szczecinie

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2006

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nr 11 (83)

131-140

PL

Artykuł przedstawia metodykę wyznaczania współczynników sił aerodynamicznych statku z wykorzystaniem numerycznej dynamiki płynów. Obliczenia numeryczne zostały zweryfikowane z wynikami uzyskanymi w tunelu aerodynamicznym. Pokazano również sposób ułożenia siatki i jej późniejszej adaptacji w celu dopasowania jej do lokalnych warunków przepływu. Duży nacisk w prezentowanej metodyce obliczeń położono na ograniczenia czasu generowania siatki i automatyzację procesu obliczeń.

EN

The paper presents guidelines for the determination of ship aerodynamic forces with the application of computational fluid dynamics methods. Numerical calculations were verified against the results from the wind tunnel. The techniques of grid making and furhter grid adoption for local flow characteristics were discussed. Special attention was paid to the problems of time limitations during grid generation and automation of thge computation process.

3

O obliczaniu przepustowości koryt rzecznych

Kubrak E.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2005

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Vol. 14, No. 1

29--38

EN

The calculation method of discharges capacity in rivers and channels are based on the Manning-Stricklera and Darcy-Weisbach friction factors to represent local river bed stresses coupled with other fluid dynamic processes. This paper describes the comparison of the velocities computed with the use of both methods of the evaluation of friction factors. The velocities calculated within rough zone based on Manning-Strickler and Darcy-Weisbach friction factors agree with each other for relative roughness k/4R(0.001; 0.050 ). When the relative roughness goes beyond this rangę or the flow is within smooth or transition zones, the velocities calculated on the basis of Manninga-Strickler friction factor are greater by about 20%. In rough zone there are two areas on Moody Diagram in which the ratio vST/v changes with the depth of the channel. In the transition zone the difference between the calculated velocities based on two methods inerease with the depth of the channel.