In the article, the tortuosity in randomly generated 2D pore structures with various porosity and size of a structural element forming the solid body is investigated. Two different numerical methods are applied: the L...
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In the article, the tortuosity in randomly generated 2D pore structures with various porosity and size of a structural element forming the solid body is investigated. Two different numerical methods are applied: the Lattice Boltzmann Method and the self-developed algorithm, the so-called path searching algorithm. The first method serves to calculate the hydraulic tortuosity based on the velocity field. The second method is used to detect free passages in the porous medium in the chosen space direction. In the study, 15000 different pore structures are investigated with 5 different resolutions of the numerical grid. The main result of the investigations is a new empirical function destined to estimate the tortuosity in cases where the porosity and the size of the structural element are known. Such functions are not known in the literature. (C) 2019 International Association for Mathematics and Computers in Simulation (IMACS). Published by Elsevier B.V. All rights reserved.
This paper addresses optimal motion for general machines. Approximation for optimal motion needs a global path planning algorithm that precisely calculates the whole dynamics of a machine in a brief calculation. We pr...
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ISBN:
(纸本)9781457708398
This paper addresses optimal motion for general machines. Approximation for optimal motion needs a global path planning algorithm that precisely calculates the whole dynamics of a machine in a brief calculation. We propose a path planning algorithm that is composed of a path searching algorithm and a pruning algorithm. The pruning algorithm is based on our analysis for the resemblances of states. To confirm the precision, calculation cost, optimality, and applicability of the proposed algorithm, we conducted several shortest time path planning examinations for the dynamic models of double inverted pendulums. The precision to reach the goal state of the pendulums was better than other algorithms. The calculation was at least 58 times faster. There was a positive correlation between the optimality and the resolutions of the proposed algorithm. As a result of torque based feedback control simulation, we confirmed applicability of the proposed algorithm under noisy situation.
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