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  • 0 赞同
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    Y

    已经解决。
    (在一个视频中提到这一点)网格统计问题有三种情况:
    第一种,是显示问题的网格数目很少,就几个,占总体的0.0002%。对于这种情况直接更改限定值。
    第二种,是显示问题的网格数目很多,占总体的超过10%,甚至更多,对于这种情况需要更改MeshData的参数设置,重新对网格进行绘制。
    必须保证,不能出现负网格。

  • twoPhaseEulerFoam

    Algorithm
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    金石为开

    @cfd-china 可以私发给我呀,肯定有帮助的~谢谢~1277909926@qq.com

  • 关于流场初始化的疑问

    Algorithm
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    L

    本人小白,有个疑问:为什么在做流体仿真的时候设置完边界条件后,还要进行初始化后才能开始计算。而做固体有限元分析的时候设置完边界条件后就可以直接开始计算了?照理说微分方程有边界条件后就可以确定唯一的解了,想不明白初始化的目的是什么,各位老师可不可以深入浅出的给我讲解一下?谢谢

  • M1制作免费ubuntu虚拟机

    CFD彩虹条
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    R

    感谢分享。不过虚拟机的话用UTM(免费)很方便,直接加载官方镜像安装即可。我在UTM里的Ubuntu20.04(Focal)里成功编译了OF8,9和OF v2012。

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    bestucanB

    @jdzhang 你的颗粒会动么?不会动,为什么颗粒间还有距离?会动,那对着“多相流”查比对着“多孔介质”查更容易找到解决方案些。

    这有一个画网格的:
    https://www.bilibili.com/video/BV1eS4y1F7Wm/?vd_source=c01e8d4fff0db460c75b32e0d0191b24

    这有些相关的:
    https://www.researchgate.net/publication/308996206_Pore-scale_numerical_simulation_of_mud_erosion_in_the_subsea_sand-mud_alternate_layer_using_lattice_Boltzmann_method

    https://ascelibrary.org/doi/10.1061/(ASCE)HY.1943-7900.0001489

  • 关于加载用于自定义函数

    Fluent
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    I

    可以加载多个

  • 关于网格局部加密问题

    Meshy
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    W

    周老师,这里我测试发现好像这种结构网格的加密方式对于三维模型可以,对于二维网格,在经过局部加密后再导入到OF里面是会报错的,错误是:--> FOAM FATAL ERROR:
    face 11528151 does not belong to cell 210100. Face owner: -1 neighbour: 210099

    From Foam::cellShape Foam::extrudedQuadCellShape(Foam::label, const labelList&, const faceList&, const labelList&, const labelList&, Foam::label, Foam::faceList&) in file extrudedQuadCellShape.C at line 105.

    FOAM aborting
    感觉好像是在z方向拉伸出来的面没有识别到具体的cell中

  • 搅拌反应器ICEM结构网格划分方式

    Meshy
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    C

    @李东岳 好的,谢谢李老师耐心解答

  • CFD和LBM的优劣势

    CFD彩虹条
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    C

    @leo_chou 大批量的工业算例(本身可能不复杂,但就是工况多),LBM是不是也需要大规模网格和较长时间?工业应用CFD对时间的要求基本上是小时级别的。

    另外好奇问下,复杂几何下的LBM如何,需要湍流的LBM呢?我觉得大部分案例,复杂几何+湍流模型是标配,没有湍流的话可能有多相或者化学反应啥的,这些LBM是不是会更强一些?

  • turbulence里k设置的问题

    OpenFOAM
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    Cloud1990C

    @李东岳 在 turbulence里k设置的问题 中说:

    你这个可以通过codedfixedvalue来实现,在论坛里有代码你找找这个关键词。我现在手机写不了代码,找不到再回帖。

    还有一个方法上是用timeVaryingMappedFixedValue这个boundary condition。

    参见tutorials/incompressible/simpleFoam/pitzDailyExptInlet。

    需要在constant里建立一个boundaryData的文件,一般只要给定0 时刻分布,就相当于给定constant分布。

    boundaryData中点的坐标和具体数值可用python或matlab自行生成。

    必须注意的是,boundaryData里面文件的具体格式,不同版本OpenFOAM可能不同。

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    我真的发现,凡是写“求大神指导的”,下面的回复就是这样的

  • MAC

    Algorithm
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    Elibathe康E

    倒是没有在研究这个,最近在用有限体积法求解翼型绕流流函数的问题,用到一点点。谢谢你,我找来看一下:happy:

  • Ubuntu 关掉特效

    OpenFOAM
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    李东岳
    sudo apt-get install compizconfig-settings-manager compiz-plugins-extra

    然后运行。

  • CFD青年成长支持计划(2021)

    公告
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    F

    想问一下李老师这个计划还有吗!!很想要这本湍流模型:mianmo:

  • 0 赞同
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    P

    英国谢菲尔德大学(The University of sheffield)Energy2050团队(http://energy2050.ac.uk)在招一个做CFD方向的全奖博士,做旋转填料床反应器捕捉二氧化碳的CFD仿真研究,对此职位感兴趣的研究生或者优秀本科毕业生可以申请(可直博),目前的申请截止日期是2022年7月22日(可能推迟),如来不及,入学时间可推迟到明年一月。

    谢菲尔德大学,世界百强名校,著名的CFD仿真软件Fluent的发源地,课题组学术氛围很好,适合静心搞科研。课题组在CFD领域有几十年的研究基础,在CCUS领域有丰富的研究资源,课题紧扣国内火热的"双碳"主题,该细分方向组里有7年的研究基础了,可以在前人的基础上接着做。

    具体招聘信息如下:
    We have a fully funded PhD studentship and look for applicants open to both UK and international students: Engineering doctorate (EngD): Predicting performance of intensified carbon capture inside rotating packed beds using CFD modelling

    If you know any good students from China, or the UK, please encourage them to apply.
    Any questions then let them to contact Professor Lin Ma: https://www.sheffield.ac.uk/mecheng/people/academic/lin-ma

    The advert is on findaphd.com: https://www.findaphd.com, search for the project 搜索 predicting performance of intensified carbon capture inside rotating packed beds using cfd modelling。

    或直接通过以下链接:https://www.findaphd.com/phds/project/engineering-doctorate-engd-predicting-performance-of-intensified-carbon-capture-inside-rotating-packed-beds-using-cfd-modelling/?p145128#opennewwindow

    Please make sure that they apply through the university of sheffield website: https://www.sheffield.ac.uk/postgraduate/phd/apply/applying.

    课题介绍:

    Carbon capture is considered the only technology able to decarbonise the hard-to-abate industries. many of these industries utilise legacy sites with little space for large new unit operations required in conventional carbon capture. rotating packed beds (RPB) look to solve this problem by intensifying carbon capture and reducing the footprint required by up to ten times, while also significantly decreasing the capital cost of these units. when combined with proprietary solvents, it is believed the cost of capture can be reduced to $30/tonne CO2 in some cases, helping to enable the rapid uptake of carbon capture and progression towards net zero.

    RPB are a novel technology that utilise the principles of process intensification to enhance the performance of mass transfer processes between fluids. given the application of rpb to the field of CO2 capture is relatively new, there is uncertainty regarding the impact of different process variables on the performance of the rpb that would otherwise require a significant amount of practical experimentation to investigate. computational fluid dynamics can enable the process to be accurately modelled, allowing for quick and inexpensive prediction of performance under various conditions.

    In this project a rotating packed bed absorber will be modelled in ansys fluent, with validation of the model’s outputs through use of the 1 tonnes of co2 per day (TPD) pilot-scale rotating packed bed absorber at the university of sheffield’s translational energy research centre. Initial research will involve investigating the impact of operational conditions and physical properties of the solvent on capture performance. As the project continues, the scope will widen to include sensitivity analysis of design parameters and the impact of scaling the RPB absorber on the existing project outputs and learnings. Additionally, further rotating unit operations could also be investigated.

    This project will utilise and develop your knowledge surrounding CFD modelling, mass and heat transfer, reaction kinetics and chemical equilibria. You will work closely with carbon clean, a global leader in the development of carbon capture technology and pioneers in the use of RPB for industrial decarbonisation. Your findings could directly impact the design and operation of commercial working carbon capture facilities, supporting the pathway to net zero.

    We are seeking applicants to start in september 2022.

    The project will be part of the EPSRC-supported centre for doctoral training in resilient decarbonised fuel energy systems. The student who undertakes it will be one of a cohort of over 50 students in a broad range of disciplines across the universities of sheffield, nottingham and cardiff.

    The research work will be based in the energy research group within the department of mechanical engineering and the translational energy research centre (TERC) at sheffield which is a brand new, high profile, innovation focused national research facility. You will be working within an exciting and dynamic group with approximately over 60 researchers undertaking a broad area of energy research with approximately three years' extensive research time in industry, preparing for high-level careers in the energy sector.

    Funding notes
    The studentship will cover full university fees and a tax-free, enhanced annual stipend of £20,352, including £16,062 (2022/2023) a year for four years and a stipend enhancement of £3,750 per annum.

    英国的全奖机会非常少,机会难得,欢迎各位优秀的CFDer申请!

  • 0 赞同
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    bestucanB

    @李东岳 我就记得我之前搞过,后来坑太深了,就没搞了。

    这些涉及到图形处理的各个层,又是平台不同,又是商业公司夹私货,那些个组件的名字本来就乱七八糟,缩写规则还不一样。想短时间了解就更乱。

    大概就是,可以软件渲染(OSMesa),可以硬件渲染(EGL)。
    其实都是基于Open GL,就这三个英语词空格隔开一起搜都一大堆讲更多术语关系的文章。

    paraview 默认用软件渲染,想要硬件渲染把 EGL 编译选项打开就行了,这就有个忘了打开报错的:
    https://discourse.paraview.org/t/build-paraview-for-nvidia-gpu/8309
    但这个是单GPU的,不知道多GPU的怎么搞,

    我的GPU是当显卡用的,一开paraview就调用GPU,当然是为“图形界面渲染"的,不是为“paraview渲染”的,这俩还都是opengl下面的,那些名词太乱了。

    我试着编了一下 pvserver能多线程跑在GPU上,
    Screenshot from 2022-06-11 15-52-46.png
    就是这个方法:
    https://github.com/Kitware/ParaView/blob/master/Documentation/dev/build.md

    当然编译之前已经安装好nvidia自带的驱动了。

    nvidia 早些年自己出过 paraview 的插件:
    https://www.nvidia.com/en-us/data-center/index-paraview-plugin/
    不过是针对 paraview 5 的

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    B

    @LuoS 在 snappyHexMesh对复杂地形添加边界层报“浮点数例外 (核心已转储)”错误 中说:

    教程中似乎有个建筑风的案例:
    /Tutorials/inco

    好的谢谢 我试一下

  • openfoam,导入,ansys

    Fluent
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    I

    进展怎么样?

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    getdata取点;
    给原作者发个邮件问一下;
    这个图是excel 做的吧

    你可以用excel 也可以用origin

  • 大家发朋友圈越来越少了

    CFD彩虹条
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    @李东岳 这两年的学生真的是过的没劲。。