Zirui Mao, PhD

Zirui Mao, PhD

Postdoc, PCSD, PNNL

Posts by Collection

portfolio

Lid-driven cavity flow

2015.09-2016.06 / PhD side project @ UC: FDM simulation of cavity flow driven by moving lid

publications

A comprehensive study on the parameters setting in smoothed particle hydrodynamics (SPH) method applied to hydrodynamics problems

Published in Computers & Geotechnics, 2017

How to cite

Mao Z, Liu GR, Dong X. A comprehensive study on the parameters setting in smoothed particle hydrodynamics (SPH) method applied to hydrodynamics problems. Comput Geotech. 2017;92:77‐95. https://doi.org/10.1016/j.compgeo.2017.07.024. [manuscript]

Abstract

Smoothed particle hydrodynamics (SPH) is a meshfree, Lagrangian particle method which has advantages in handling solids with extremely large deformation. Like any other numerical methods, cares must be taken to ensure its desirable accuracy and stability through considering several correction techniques in calculation. The selection of values for parameters in those correction approaches is a key step in SPH simulation, which is always difficult for new beginners to deal well with effectively. This paper examines the common inconsistency and instability problems in SPH method and studies its computational efficiency when applied to hydrodynamics problems with material strength like soil column collapse. We analyzed in detail how the correction techniques mitigate these inconsistency and instability problems. Also, the numerical testing results associate with different values for the parameters used in the correction techniques are provided for better understanding the influence of these parameters and for finding out the desirable values. It is found that (1) the SPH method is easily subjected to an inconsistency problem in the boundary area due to the boundary deficiency, and it can be treated well by adopting “virtual particles” contributing to the particle summations. (2) The numerical oscillation in SPH simulation can be mitigated effectively by artificial viscosity with the suggested parameter values. (3) The tension cracking treatment, artificial viscosity and artificial stress work well in removing the tensile instability problem in SPH method. In addition, the nearest neighboring particle searching (NNPS) algorithm, spacing ratio, smoothing length and time step influence the efficiency and accuracy of SPH method significantly. It is shown that SPH method with suggested parameters values can produce a very good result compared with the experimental result.

Keyword

Smoothed Particle Hydrodynamics, hydrodynamics with material strength, soil column collapse, tensile instability and artificial stress, artificial viscosity

Perfectly matched layer absorbing boundary conditions for Euler equations with oblique mean flows modeled with smoothed particle hydrodynamics

Published in The Journal of the Acoustical Society of America, 2020

How to cite

Jie Yang, Xinyu Zhang, G. R. Liu, Zirui Mao, and Wenping Zhang, Perfectly matched layer absorbing boundary conditions for Euler equations with oblique mean flows modeled with smoothed particle hydrodynamics, The Journal of the Acoustical Society of America, Volume 147, Issue 2, 1311 (2020). https://doi.org/10.1121/10.0000648.

A 3D Lagrangian gradient smoothing method framework with an adaptable gradient smoothing domain‐constructing algorithm for simulating large deformation free surface flows

Published in International Journal for Numerical Methods in Engineering, 2020

How to cite

Mao, Z, Liu, GR. A 3D Lagrangian gradient smoothing method framework with an adaptable gradient smoothing domain‐constructing algorithm for simulating large deformation free surface flows. Int J Numer Methods Eng. 2020; 121: 1268– 1296. https://doi.org/10.1002/nme.6265. [manuscript]

talks

teaching

Physic-based models for material processing

MATLAB, in-house code, 2019

Three highly efficient physics-based models are developed in Matlab for predicting the mechanical behaviors of material during processing: large deformation, bound strength, and failure. The software is archived by P&G and here are some samples.

L-GSM platform

FORTRAN & MATLAB, in-house code, 2021

The L-GSM platform provides a meshfree method for handling large deformation problems with a much better performance in stability and efficiency. Applications can be found here. The in-house code will be released as planned.

Phase-Field platform

FORTRAN & MATLAB, in-house code, 2021

The Phase-Field platform solves the general Allan-Cahn and Cahn-Hilliard equations using Finite Difference Method (with uniform grid) or Gradient Smoothing Method (with adaptive grid). Two numerical solvers are provided: a simple explicit solver and an efficient implicit solver. The in-house code will be released as planned associated with upcoming paper publication.

Optimal Controller of microstructure’s evolution

FORTRAN & MATLAB & Python, in-house code, 2021

This software enables optimal control of microstructure’s evolution through coupling phase-field models with reinforcement learning algorithms. The microstructure can be guided from any initial, unstructured state to any target state with the least cost. Please refer to the examples.

1D diffusion freeware

Matlab GUI, Tutorial freeware, 2021

This tutorial freeware (1D diffusion software) aims at providing students/new beginners a direct computational tool for understanding diffusion type of problems in engineering and material science.

1D Phase Field software

Matlab GUI, Tutorial freeware, 2021

This tutorial freeware (1D Phase Field software) aims at providing students/new beginners a direct computational tool for understanding material microstructure evolution in engineering and material science.

Adaptive remeshing for GSM

MATLAB, in-house code, 2022

This software enables adaptive remeshing based on moving material features for Gradient Smoothing Method.

GPU accelerated mixed-precision SPH framework

CUDA and Fortran, Open source, 2023

Herein, we introduce a GPU-accelerated mixed-precision SPH framework by using low precision FP16 in NNPS while maintaining high-precision FP64 in other components.