Author Archives: news

Coupling OpenFOAM with FeniCS for multiphysis simulation (OpenFOAM workshop 13 presentation)

Posted on June 25, 2018 by news

This is my presentation for OpenFOAM workshop 13 presentation, unfortunately, I can not attend the workshop in person. Link to my presentation PDF: OFW13-19-119__Coupling_OpenFOAM_with_FeniCS_for_multiphysis_simulation__QingfengXIA Outline of this presentation: 1. physics simulation automation 2. CFD module for FreeCAD (GUI for OpenFOAM) … Continue reading →

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preCICE build and test on Ubuntu 16.04

Posted on June 22, 2018 by news

please read PDF version for better code highlighting preCICE build and test on Ubuntu 16.04

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FreeCAD 0.17 + OpenFOAM CFD module now works on windows 10 WSL

Posted on May 6, 2018 by news

after windows 10 2018 april update, it is possible to run my CFD module on FreeCAD 0.17 Limited by my time I can spend on this open source project, I will will make new feature in about half year, but … Continue reading →

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I have developed several multi-physics solver based on Fenics and GUI within FreeCAD CFD workbench

Posted on November 27, 2017 by news

This is also announced in Fenics support forum Screenshot of FenicsSolver in FreeCAD Dear all, I have developed several multi-physics solver based on Fenics, it is hosted on github: https://github.com/qingfengxia/FenicsSolver This solver is data driven (json), instead of programming … Continue reading →

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Add visual studio command prompt to windows explorer context menu

Posted on November 5, 2017 by news

Recently relised visual studio build tool (with cmake support), enables building windows c++ project without GUI. It is essential to accelerate the testing of cross-platform program. It is convenient and decent to add Bash (WSL) and visual studio command line … Continue reading →

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using cloud space as a private git repo

Posted on September 24, 2017 by news

[answer from stackoverflow] It is absolutely possible – what you probably want to do is create a “bare” git repository in folder Y (git init –bare) and then add that file location as a remote:

git remote add Y file:///path/to/Y
#example path: file:///media/sf_OneDrive/gitr<wbr />epo/FenicsSolver/

1 2	git remote add Y file:///path/to/Y #example path: file:///media/sf_OneDrive/gitr<wbr />epo/FenicsSolver/

======= push and pull … Continue reading →

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BoundaryLayer setup for Gmsh 3D meshing

Posted on June 16, 2017 by news

Precise control of the thickness of the first cell normal to wall, is crucial for turbulence models like k-epsilon, k-omega. Before moving to turbulence flow simulation for CFD workbench of FreeCAD 2D meshing with boundary layer, tutorial <http://www.iesensor.com/blog/2017/05/24/gmsh_fenics_meshing/> 3D boundary … Continue reading →

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from gmsh geo file to fenics mesh with subdomain and boundary facet exported

Posted on May 24, 2017 by news

from dolfin import *
import os.path
from subprocess import Popen, PIPE, check_output

# https://fenicsproject.org/qa/9983/setting-boundary-conditions-for-meshes-generated-by-gmsh
# generete mesh by: gmsh test.geo -3
# dolfin-convert -i gmsh test.msh test.xml

geo_file_content = """
size = 1; //m
meshThickness = size / 3; 
gridsize = size / 5;

// All numbering counterclockwise from bottom-left corner
Point(1) = {0, 0, 0, gridsize};
Point(2) = {0, size, 0, gridsize};
Point(3) = {size, size, 0, gridsize};
Point(4) = {size, 0, 0, gridsize};
Line(1) = {1, 2};               
Line(2) = {2, 3};           
Line(3) = {3, 4};       
Line(4) = {4, 1};       
Line Loop(4) = {1, 2, 3, 4};
Plane Surface(8) = {4};
Physical Line(12) = {1};
Physical Line(23) = {2};
Physical Line(34) = {3};
Physical Line(41) = {4};

Physical Surface(1) = {8};  // do not comment out this line

//Transfinite Surface{8};  // fenics does not support recomine
//Recombine Surface{8};


// boundary layer
Field[4] = BoundaryLayer;
Field[4].EdgesList = {1,3};  // FacesList  for 3D
Field[4].hfar = 10;
Field[4].hwall_n = 0.015;
Field[4].hwall_t = 0.01;
Field[4].thickness = 0.02;
Field[4].ratio = 1.0;

BoundaryLayer Field = 4;

Mesh.CharacteristicLengthFromCurvature = 1;
Mesh.Algorithm = 8; // delannay=1
"""

fname="test"
with open(fname+".geo", 'w') as f:
    f.write(geo_file_content)

cmd = 'gmsh {}.geo -3'.format(fname)
print check_output([cmd], shell=True)  # run in shell mode in case you are not run in terminal

cmd = 'dolfin-convert -i gmsh {}.msh {}.xml'.format(fname, fname)
Popen([cmd], stdout=PIPE, shell=True).communicate()

mesh = Mesh(fname+".xml")
if os.path.exists( fname+"_physical_region.xml"):
    subdomains = MeshFunction("size_t", mesh, fname+"_physical_region.xml")
    plot(subdomains)
if os.path.exists( fname+"_facet_region.xml"):
    boundaries = MeshFunction("size_t", mesh, fname+"_facet_region.xml")
    plot(boundaries)

plot(mesh)
interactive()

from dolfin import *

import os.path

from subprocess import Popen, PIPE, check_output

# https://fenicsproject.org/qa/9983/setting-boundary-conditions-for-meshes-generated-by-gmsh

# generete mesh by: gmsh test.geo -3

# dolfin-convert -i gmsh test.msh test.xml

geo_file_content = """

size = 1; //m

meshThickness = size / 3;

gridsize = size / 5;

// All numbering counterclockwise from bottom-left corner

Point(1) = {0, 0, 0, gridsize};

Point(2) = {0, size, 0, gridsize};

Point(3) = {size, size, 0, gridsize};

Point(4) = {size, 0, 0, gridsize};

Line(1) = {1, 2};

Line(2) = {2, 3};

Line(3) = {3, 4};

Line(4) = {4, 1};

Line Loop(4) = {1, 2, 3, 4};

Plane Surface(8) = {4};

Physical Line(12) = {1};

Physical Line(23) = {2};

Physical Line(34) = {3};

Physical Line(41) = {4};

Physical Surface(1) = {8}; // do not comment out this line

//Transfinite Surface{8}; // fenics does not support recomine

//Recombine Surface{8};

// boundary layer

Field[4] = BoundaryLayer;

Field[4].EdgesList = {1,3}; // FacesList for 3D

Field[4].hfar = 10;

Field[4].hwall_n = 0.015;

Field[4].hwall_t = 0.01;

Field[4].thickness = 0.02;

Field[4].ratio = 1.0;

BoundaryLayer Field = 4;

Mesh.CharacteristicLengthFromCurvature = 1;

Mesh.Algorithm = 8; // delannay=1

"""

fname="test"

with open(fname+".geo", 'w') as f:

f.write(geo_file_content)

cmd = 'gmsh {}.geo -3'.format(fname)

print check_output([cmd], shell=True) # run in shell mode in case you are not run in terminal

cmd = 'dolfin-convert -i gmsh {}.msh {}.xml'.format(fname, fname)

Popen([cmd], stdout=PIPE, shell=True).communicate()

mesh = Mesh(fname+".xml")

if os.path.exists( fname+"_physical_region.xml"):

subdomains = MeshFunction("size_t", mesh, fname+"_physical_region.xml")

plot(subdomains)

if os.path.exists( fname+"_facet_region.xml"):

boundaries = MeshFunction("size_t", mesh, fname+"_facet_region.xml")

plot(boundaries)

plot(mesh)

interactive()

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FreeCAD compatible Fenics mshr geometry building

Posted on February 27, 2017 by news

Fenics geometry building API is based on CGAL, it can import CAD, but can not export CAD file like step. Here is a solution, not fully tested. This file may be further developed in github.

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solved Fenics (2016.2) cpp code compiling error on ubuntu 16.04

Posted on February 27, 2017 by news

for any expression in Expression for Fenics 2016.2( installed from PPA ) expr = “”” x[2]> {} ? {}:{}”””.format(disc_zmax, lambda_p, lambda_d) print(expr) K = Expression(expr, element=V.ufl_element()) # error in compiling instant error log: ” — The imported target “vtkRenderingPythonTkWidgets” references … Continue reading →

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Cmake cheatsheet

Posted on December 24, 2016 by news

#Cmake cheat sheet in markdown

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c and cpp pitfalls, mixing signed and unsigned integer, implicit conversion

Posted on December 21, 2016 by news

1. mixing unsigned and sign int is a bad idea first of all, remember: signed int types will be implicitly converted to unsigned if sizeof(signed int types) == sizeof(unsigned int types) Google C++ coding standard, say “do not use unsigned … Continue reading →

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compile c++ codes using Visual C++ Build Tools from the command prompt

Posted on December 6, 2016 by news

Introducing the Visual Studio Build Tools “If you have installed Microsoft Visual C++ Build Tools 2015 on Windows 10, open the Start menu and choose All apps. Scroll down and open the Visual C++ Build Tools folder. Choose Visual C++ … Continue reading →

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Mibox 2 install youtube and play to kodi (just as chromecast)

Posted on November 8, 2016 by news

1. install shafa TV manager and/or ES file explorer to be enable install apk from USB/SD card http://www.shafa.com/articles/yWNpNK6erhB6Q4dO.html 2. install Kodi/XMBC apk from shafa’s file manager (in toolbox) on USB storage 3. install apk of youtube for Google TV, and … Continue reading →

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Evaluation of OpenFOAM on bash on Ubuntu on windows 10

Posted on September 4, 2016 by news

## installation After Anniversary Build (2016 Aug) for x65 windows 10, it is possible to evaluate this beta feature in developer mode without upgrade to claimed unstable insider version. see detailed tutorial: To install ubuntu on windows 10 from power … Continue reading →

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disable windows input method hotkey

Posted on August 21, 2016 by news

UPDATE: it seems the following methods still fails, as restart pc or windows update will invalidated the setting =========== Avoid the annoying hotkey to trigger the IME shape/punctation in Chinese for half/full see tutorial: http://superuser.com/questions/327479/ctrl-space-always-toggles-chinese-ime-windows-7 In addition to disapble Ctrl-Space, … Continue reading →

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Toshiba L650 laptop disassembling

Posted on May 29, 2016 by news

I got a 5 year old laptop, it does not boot, no screen show, no beeping. So I need to disassemble and check. Generally, this laptop is easy to repalce harddisk or memory on the back. And the dissabling is … Continue reading →

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Introduction to Industrial IO (sensor framework for Linux)

Posted on May 29, 2016 by news

introduciton to Industrial IO overview of industrial IO. In short, SPI and I2C sensor framework for Linux sensor categories: “ADC, DAC, light, accel(erometer), gyro, magnetometer, humidity, temperature, amplifier, frequency, orientation, health”, etc merged to mainline kernel 3.14, used by beagleBone, … Continue reading →

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A recommendation for free of charge 2D CAD and office system, also cross-platform

Posted on May 17, 2016 by news

for office system, I recommend kingsoft WPS office, which is based on Qt, much faster than java based solution. It has Android, Linux version in alpha, in addition to mature windows ‘s version http://wps-community.org/download.html For 2D CAD drawing, I recommend … Continue reading →

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Solve CFD via OpenFOAM in free CAx platform FreeCAD

Posted on January 24, 2016 by news

Updated 2016-04-17 Boundary condition setup GUI has been done for preview This is an early preview, only for people with experience of OpenFoam. Test instruction could be found at https://github.com/qingfengxia/FreeCAD/ … /Readme.md I would love to see some feedback for … Continue reading →

Posted in Linux, Programming, Research | Comments Off

Author Archives: news

Coupling OpenFOAM with FeniCS for multiphysis simulation (OpenFOAM workshop 13 presentation)

preCICE build and test on Ubuntu 16.04

FreeCAD 0.17 + OpenFOAM CFD module now works on windows 10 WSL

I have developed several multi-physics solver based on Fenics and GUI within FreeCAD CFD workbench

Add visual studio command prompt to windows explorer context menu

using cloud space as a private git repo

BoundaryLayer setup for Gmsh 3D meshing

from gmsh geo file to fenics mesh with subdomain and boundary facet exported

FreeCAD compatible Fenics mshr geometry building

solved Fenics (2016.2) cpp code compiling error on ubuntu 16.04

Cmake cheatsheet

c and cpp pitfalls, mixing signed and unsigned integer, implicit conversion

compile c++ codes using Visual C++ Build Tools from the command prompt

Mibox 2 install youtube and play to kodi (just as chromecast)

Evaluation of OpenFOAM on bash on Ubuntu on windows 10

disable windows input method hotkey

Toshiba L650 laptop disassembling

Introduction to Industrial IO (sensor framework for Linux)

A recommendation for free of charge 2D CAD and office system, also cross-platform

Solve CFD via OpenFOAM in free CAx platform FreeCAD

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