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Title: SPH with dynamical smoothing length adjustment based on the local flow kinematics

Abstract

Due to the Lagrangian nature of Smoothed Particle Hydrodynamics (SPH), the adaptive resolution remains a challenging task. In this work, we first analyse the influence of the simulation parameters and the smoothing length on solution accuracy, in particular in high strain regions. Based on this analysis we develop a novel approach to dynamically adjust the kernel range for each SPH particle separately, accounting for the local flow kinematics. We use the Okubo–Weiss parameter that distinguishes the strain and vorticity dominated regions in the flow domain. The proposed development is relatively simple and implies only a moderate computational overhead. We validate the modified SPH algorithm for a selection of two-dimensional test cases: the Taylor–Green flow, the vortex spin-down, the lid-driven cavity and the dam-break flow against a sharp-edged obstacle. The simulation results show good agreement with the reference data and improvement of the long-term accuracy for unsteady flows. For the lid-driven cavity case, the proposed dynamical adjustment remedies the problem of tensile instability (particle clustering).

Authors:
; ;
Publication Date:
OSTI Identifier:
22701616
Resource Type:
Journal Article
Journal Name:
Journal of Computational Physics
Additional Journal Information:
Journal Volume: 348; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9991
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; LAGRANGIAN FUNCTION; MATHEMATICAL SOLUTIONS; TWO-DIMENSIONAL CALCULATIONS; UNSTEADY FLOW

Citation Formats

Olejnik, Michał, Szewc, Kamil, and Pozorski, Jacek. SPH with dynamical smoothing length adjustment based on the local flow kinematics. United States: N. p., 2017. Web. doi:10.1016/J.JCP.2017.07.023.
Olejnik, Michał, Szewc, Kamil, & Pozorski, Jacek. SPH with dynamical smoothing length adjustment based on the local flow kinematics. United States. doi:10.1016/J.JCP.2017.07.023.
Olejnik, Michał, Szewc, Kamil, and Pozorski, Jacek. Wed . "SPH with dynamical smoothing length adjustment based on the local flow kinematics". United States. doi:10.1016/J.JCP.2017.07.023.
@article{osti_22701616,
title = {SPH with dynamical smoothing length adjustment based on the local flow kinematics},
author = {Olejnik, Michał and Szewc, Kamil and Pozorski, Jacek},
abstractNote = {Due to the Lagrangian nature of Smoothed Particle Hydrodynamics (SPH), the adaptive resolution remains a challenging task. In this work, we first analyse the influence of the simulation parameters and the smoothing length on solution accuracy, in particular in high strain regions. Based on this analysis we develop a novel approach to dynamically adjust the kernel range for each SPH particle separately, accounting for the local flow kinematics. We use the Okubo–Weiss parameter that distinguishes the strain and vorticity dominated regions in the flow domain. The proposed development is relatively simple and implies only a moderate computational overhead. We validate the modified SPH algorithm for a selection of two-dimensional test cases: the Taylor–Green flow, the vortex spin-down, the lid-driven cavity and the dam-break flow against a sharp-edged obstacle. The simulation results show good agreement with the reference data and improvement of the long-term accuracy for unsteady flows. For the lid-driven cavity case, the proposed dynamical adjustment remedies the problem of tensile instability (particle clustering).},
doi = {10.1016/J.JCP.2017.07.023},
journal = {Journal of Computational Physics},
issn = {0021-9991},
number = ,
volume = 348,
place = {United States},
year = {2017},
month = {11}
}