Open Access

ARTICLE

A Simplified Approach of Open Boundary Conditions for the Smoothed Particle Hydrodynamics Method

Thanh Tien Bui^1,*, Yoshihisa Fujita², Susumu Nakata²

1 Graduate School of Information Science and Engineering, Ritsumeikan University, Shiga, 525-8577, Japan
2 College of Information Science and Engineering, Ritsumeikan University, Shiga, 525-8577, Japan

* Corresponding Author: Thanh Tien Bui. Email:

Computer Modeling in Engineering & Sciences 2021, 129(2), 425-442. https://doi.org/10.32604/cmes.2021.016766

Received 24 March 2021; Accepted 12 July 2021; Issue published 08 October 2021

Abstract

In this paper, we propose a simplified approach of open boundary conditions for particle-based fluid simulations using the weakly compressible smoothed-particle hydrodynamics (SPH) method. In this scheme, the values of the inflow/outflow particles are calculated as fluid particles or imposed desired values to ensure the appropriate evolution of the flow field instead of using a renormalization process involving the fluid particles. We concentrate on handling the generation of new inflow particles using several simple approaches that contribute to the flow field stability. The advantages of the . -SPH scheme, specifically the particle shifting technique, were successfully applied to correct the position, velocity, and pressure terms of the particles. Therefore, unexpected errors were removed and tensile instabilities of the particles were prevented. The proposed technique is validated for several benchmark test cases, and the tests show that the results match the reference solutions well. A viscous open-channel flow is used to demonstrate the stability of the flow field during the computational time. Based on this stability, we compress the computational domain to a lower resolution in a second test case while preserving the accuracy of the simulation. Flow over a backward-facing step is used to highlight the challenges of inflow boundary conditions with prescribed or non-prescribed values. The developed technique is well suited to the wall boundaries and the evolution of the flow field. The results demonstrate the robustness and versatility of the proposed technique for a variety of simulations.

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Keywords

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