Skip to content
  • dpm模型模拟闪蒸

    Fluent
    1
    0 赞同
    1 帖子
    2k 浏览

    请问一下各位大佬,在使用dpm模拟液滴闪蒸时,液滴沸点设置为373k,液滴温度设置为400k,连续相温度为300k,连续相介质为空气,采用双向耦合进行计算,当液滴颗粒射入连续相中时,连续相喷嘴处的温度就迅速上升,可达上千度,甚至报温度超限的错误,请问一下这是为什么呀![QQ图片20230818084454.jpg

  • ICEM非结构网格的Max element问题

    Meshy
    1
    0 赞同
    1 帖子
    4k 浏览

    请教一个比较初级的问题,查了帮助文档没有找到想得到的答案。
    ICEM采用Octree方法划分非结构网格的时候,帮助文档和网上的一些教程中都写到:“建议全局网格参数设置中的Max element值要是2的幂”
    这里2的幂是指:2的正整数幂?2的正数幂?2的实数幂?
    实际测试过感觉比如填0.05啥的也可以划分,网格也确实要比2的密很多。所以想问下各位高手这里这个数值填写应该有什么经验或者规律呢?尤其是模型尺寸很小的话,有时候确实需要很小的尺寸啊~

  • 0 赞同
    4 帖子
    7k 浏览

    用于求解不可压的pseudo-compressible method, 被认为有更好的收敛特性,见A. J. Chorin, JCP, 1967, pp. 12-26

  • 关于入口湍流边界条件

    OpenFOAM
    3
    0 赞同
    3 帖子
    5k 浏览
    E

    @东岳 嗯嗯,谢谢李老师,昨天周老师帮我向您请教了一些,我目前研究大气湍流流动,所以希望入口能满足真实环境的条件;我再研究一下相关文献,谢谢。

  • 0 赞同
    1 帖子
    2k 浏览
    L

    标准的限制方法是保证插值后网格顶点(vertice)的值不会出现极大值或极小值(比周围网格的最大值大或比周围网格的最小值小)因为梯度插值最容易出现越界值的就是在顶点处,从而用一个标量来scale梯度gradient;另外一种方法是保证网格的面心midponts of cell faces处不出现极大值或极小值即可,就认为满足了插值后不存在越界的问题。我想的是关于第二种方法,面心处插值后不出现最大值或最小值不能代表顶点处不出现最值,对吗

  • 翻到之前的基金申请拒信

    CFD彩虹条
    6
    0 赞同
    6 帖子
    8k 浏览
    李东岳

    不知道他们几千万的CFD算法研究经费都是怎么构成的 :143:

  • 喷嘴建模问题

    OpenFOAM
    4
    0 赞同
    4 帖子
    6k 浏览
    C

    @mohui 谢谢!

  • 0 赞同
    5 帖子
    11k 浏览
    txwwbzT

    @suzuhaz 大师求助帮忙看一下简单的一个模型块的划分0_1532943202163_05.zip

  • 0 赞同
    2 帖子
    5k 浏览
    李东岳

    VOF+动网格是interDyMFoam,用这个求解器就行

  • 多相液体表面网格动态加密

    Meshy
    4
    0 赞同
    4 帖子
    8k 浏览
    李东岳

    就是两种液体接触的界面部分就没有办法加密啊?

    不就是界面(表面)么?

  • latex这个代码怎么省略

    CFD彩虹条
    4
    0 赞同
    4 帖子
    4k 浏览
    L

    mark 一下

  • 0 赞同
    5 帖子
    8k 浏览

    @gsky0809 老哥,物质传输方程在哪里设置啊,我刚开始学宏观偏析,还不太懂,能指导一下吗

  • 0 赞同
    2 帖子
    5k 浏览
    李东岳

    放点图有利于讨论..

  • 论坛搜索功能挂了

    CFD彩虹条
    2
    0 赞同
    2 帖子
    3k 浏览
    李东岳

    论坛每天都有3 4万点击,一万多IP,也不知道啥时候处理好 :143:

  • 应该如何计算外部流场的k和epsilon?

    OpenFOAM
    1
    0 赞同
    1 帖子
    2k 浏览
    J

    看到站內的一篇文章, 有提及到使用turbulence length scale和turbulence intensity level来计算k和epsilon。可是查看了一下,turbulence length scale和intensity level都需要使用水力直徑来计算。那么对于外部流场来说,应该要如何计算?通常模拟汽车移动的外部流场,在OpenFOAM中,上、左和右壁都设定为slip wall,那水力直徑还应该把它当成内部流场那样以inlet的高和宽来计算吗?
    小弟的流体知识浅薄,还请多多指教:shangxue:

  • 0 赞同
    6 帖子
    8k 浏览
    李东岳

    @Yan 你出全部的图,然后只看你感兴趣的地方就可以了

  • 0 赞同
    1 帖子
    3k 浏览

    各位OF前辈你们好,我想问一个有关sampleDict提取数据的问题。
    问题是:在多域算例中,我编辑好sampleDict放入system后,然后运行“sample”,OF没有报错但是算例里面却没有生成存放数据的postProcessing文件夹。
    PS:我的算例里面分为了固体域和流体域。我的目的是提取流体域中的速度数据。(单域情况下sample是成功的,但是多域提取就总是碰到如上所述的问题。)
    sample的运行结果如下:
    272cb4cb-644f-4a44-913d-71eef27eb908-image.png
    运行sample后算例内容图如下:
    3c7a0e34-7d3e-498d-9297-003311d0a561-image.png
    可以看到,算例中没有生成任何存放提取数据的文件夹。
    下是我的sampleDict的代码:

    interpolationScheme cellPoint; setFormat csv; fields (U); sets ( lineU-bottom { type midPoint; axis distance; start (0.08 0.0025 0.0025); end (0.08 0.0025 0.0625); nPoints 150; }

    我的多域算例的结构如下:
    a15cce49-9e0d-4300-b3db-5002f9aa4c19-image.png

  • UCSD-SDSU 联合博士项目招生

    CFD彩虹条
    1
    0 赞同
    1 帖子
    2k 浏览
    O

    Job description
    We provide the opportunity for the joint Ph.D. program between UCSD and SDSU.

    Research motivation
    Do you know that measurement in a turbulent environment has its own "sixth
    sense"? In fluid dynamical systems, measurements can be used to figure out
    events that happened far away from the probing location.
    Through state-of-art data assimilation techniques, we can trace back the origin
    of any information we have measured. We used this technique to locate the
    release of a pollution release, and reconstruct unknown flow fields from limited
    measurements.

    Are you self-motivated to do a Ph.D. in interdisciplinary researches about fluid
    dynamics, inverse problems, and optimization? We are looking for Ph.D. students
    that are willing to spend time studying in an encouraging and creative
    environment!

    There has been a long-hovering question about how to combine experimental
    measurements with numerical simulations. Especially in terms of designing a
    turbulence model that agrees with experimental studies. In addition, the design
    of sensor networks or sensor weighting can be optimized in terms of the amount
    of information obtained.
    In this Ph.D. project, you will develop novel simulation techniques that combine
    machine learning techniques with data assimilation.

    The required skills and preferred profile
    We are looking for self-motivated young researchers from mechanical
    engineering, aerospace engineering, computational physics, applied mathematics,
    or other closely related areas.

    Familiar with MATLAB and FORTRAN with MPI. C++ and python is a plus. Good conceptual understanding of calculus and linear algebra. Experience with simple machine learning algorithms. Good communication skills including presentation skills, academic writing
    with latex or word. Please note that the GRE is required for all JDP applicants and cannot be
    waived. Having a part-time hobby is a plus.

    Location
    Work is carried out in the Data Assimilation group at Aerospace Engineering, San Diego State University.
    We study various inverse problems in fluid dynamics using numerical simulations
    with the discrete adjoint operator.
    For further information, please visit us at
    https://qiwang.sdsu.edu/

    Information and application
    Interested applicants should visit
    https://www.engineering.sdsu.edu/admissions/jointdoc_areomech.aspx
    for more details about applying for the joint program.
    Meanwhile, please reach out to Qi Wang (qwang4@sdsu.edu), including:
    • A short description of your qualifications and motivation to apply for this
    position.
    • CV or resume.
    • Transcripts from your Bachelor and Master degrees.
    Selected candidates will be invited to an interview and should prepare a
    scientific presentation as part of the requirements.

    We highly value diversity at our university. Applicants from all backgrounds are
    welcomed.

  • 0 赞同
    1 帖子
    2k 浏览
    L

    SPH-DEM是否适合做气液固三相搅拌

  • 如何在simpleFoam kEpsilon中加入重力?

    OpenFOAM
    4
    0 赞同
    4 帖子
    5k 浏览
    J

    @东岳 其实我是想看一下加了重力会不会对CdA和Cp做成影响 如果没有多大影响的话 就可以不考虑重力了