Wyniki wyszukiwania - BazTech

1

Path planning for an autonomous underwater vehicle in a cluttered underwater environment based on the heat method

Sun Kaiyue, Liu Xiangyang

International Journal of Applied Mathematics and Computer Science

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2021

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Vol. 31, no. 2

289--301

EN

This paper proposes a novel autonomous underwater vehicle path planning algorithm in a cluttered underwater environment based on the heat method. The algorithm calculates the isotropic and anisotropic geodesic distances by adding the direction and magnitude of the currents to the heat method, which is named the anisotropy-based heat method. Taking account of the relevant influence of the environment on the cost functions, such as currents, obstacles and turn of the vehicle, an efficient collision-free and energy-optimized path solution can be obtained. Simulation results show that the anisotropy-based heat method is able to find a good trajectory in both static and dynamic clutter fields (including uncertain obstacles and changing currents). Compared with the fast marching (FM) algorithm, the anisotropy-based heat method is not only robust, flexible, and simple to implement, but it also greatly saves time consumption and memory footprint in a time-variant environment. Finally, the evaluation criteria of paths are proposed in terms of length, arrival time, energy consumption, and smoothness.

2

The effect of multigrid parameters in a 3D heat diffusion equation

de Oliveira F., Franco S. R., Villela Pinto M. A.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 1

213--221

EN

The aim of this paper is to reduce the necessary CPU time to solve the three-dimensional heat diffusion equation using Dirichlet boundary conditions. The finite difference method (FDM) is used to discretize the differential equations with a second-order accuracy central difference scheme (CDS). The algebraic equations systems are solved using the lexicographical and red-black Gauss-Seidel methods, associated with the geometric multigrid method with a correction scheme (CS) and V-cycle. Comparisons are made between two types of restriction: injection and full weighting. The used prolongation process is the trilinear interpolation. This work is concerned with the study of the influence of the smoothing value (v), number of mesh levels (L) and number of unknowns (N) on the CPU time, as well as the analysis of algorithm complexity.

3

Verification of a binary fluid solidification model using semi-analitycal solution of 1D heat diffusion equation

Wacławczyk T., Schäfer M.

Chemical and Process Engineering

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2018

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Vol. 39, nr 1

85–-102

EN

The aim of the present work is to verify a numerical implementation of a binary fluid, heat conduction dominated solidification model with a novel semi-analytical solution to the heat diffusion equation. The semi-analytical solution put forward by Chakaraborty and Dutta (2002) is extended by taking into account variable in the mushy region solid/liquid mixture heat conduction coefficient. Subsequently, the range in which the extended semi-analytical solution can be used to verify numerical solutions is investigated and determined. It has been found that linearization introduced to analytically integrate the heat diffusion equation impairs its ability to predict solidus and liquidus line positions whenever the magnitude of latent heat of fusion exceeds a certain value.

4

Application of the BEM for numerical simulation of non-steady thermal diffusion in cylindrical domains

Majchrzak E., Dziewoński M.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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1999

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z. 10

209-214

EN

In the paper the boundary element method is used for numerical simulation of non-steady heat conduction in domains oriented in cylindrical coordinate system. The starting point of considerations is 3D problem, for which of fundamental solution is known. This function allow to determine the fundamental solution in a case of cylindrical domain. The first scheme of the BEM is applied in order to construct the numerical algorithm. In the final part of the paper the example of numerical computation is shown.

PL

W pracy wykorzystano metodę elementów brzegowych do numerycznej symulacji nieustalonego przewodzenia ciepła w obszarach zorientowanych w walcowym układzie współrzędnych. Punktem wyjściowym rozważań jest zadanie przestrzenne, dla którego znane jest rozwiązanie fundamentalne. Funkcja ta pozwala określić rozwiązanie fundamentalne dla obszarów walcowych. Przy tworzeniu algorytmu numerycznego zastosowano tzw. pierwszy schemat MEB. W końcowej części artykułu przedstawiono wyniki dla obliczeń testujących.