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OpenFOAM交流区

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  • openfoam源项发散的原因

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    K

    这样啊谢谢,我看论文中测试的时间都没有这么久,就看着能加速反应速率,时间加快些不

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    @香柏树 你这个问题解决了吗

  • 1 帖子
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    King_RVMK

    各位老师,近期在研究立管涡激振动问题,想采用切片法,主要思路是针对具有大长细比特征的立管,我想沿展长方向设置多个切片,通过求解每个切片上二维圆柱的升力和阻力来获得立管不同高度处的外力,然后再将这些外力作为输入项,自己编一段有限元程序来求解立管结构动力学问题。
    现在存在的主要问题和疑惑是:我如果想设置100个二维切片,应该采用什么样的方式实现循环求解这100个二维圆柱涡激振动问题,以及如何将这100个切片上求解得到的外力与有限元程序耦合实现流固耦合求解呢?
    想请问各位老师有什么思路吗?

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    @李东岳 好的,谢谢老师!!

  • python进行OpenFOAM流场后处理

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    @田畔的风 是的,感谢大佬,果然可以了。得抓紧学python了,批量后处理急需。
    bf4b5b57-9231-415f-b4a7-970bce7e09e5-截图_20231102134831.png

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    Z

    @李东岳 东岳博士,案例发上来了,您帮着看看

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    L

    OF中旋转轴对称怎么体现,与轴对称有什么区别,怎么设置?因为OF中没有二维网格,通过frontandback类型为empty来体现二维模型,但是怎么区别轴对称与旋转轴对称,后处理能不能转化为轴对称或者旋转轴对称?

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    自己回复自己一下吧,问题可能有些幼稚了,分享给跟我一样的小白吧。昨天晚上查了些资料解决了,syntax问题在OF的userguide里面说的很清楚,请见下图:
    image.png
    我所要表达的公式正确的写法应为:
    1.225 * pow((1 - 6.5/288.15 * H), 4.26)

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    F

    openfoam9,修改了interFoam的wave算例,波浪接触不到右边界,导致水面会一直升高,是应该改变造波的边界条件吗?
    8978e184-53b8-4fb2-8134-20d7cb8ce1a8-image.png

    0da4e1a3-0872-449b-81f2-fb3f90c82b15-52ca5aad005e7a61704afcd2ea12c6e.png

    8dcae52f-33b9-4468-8840-2b4662a564d9-e2989bf4848ad9eafea957f65955c89.png

  • cfdem未解析法网格小于颗粒大小的问题

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    cfdem小白您好,我的研究方向也是cdfem,用of+liggghts+cfdem,能否加一下联系方式多交流,我的邮箱a6160212@163.com

  • 气液两相流曳力模型问题

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    ZY-GONGZ

    各位前辈,大佬们,最近在学习中遇到了几个问题希望各位前辈指教一下:
    目前在大多数文献中我看到气液两相流中的曳力模型系数都是以下形式:
    $k=\frac{3}{4}\alpha_d\rho_c\frac{C_D}{d_d}\left|U_c-U_d\right|$
    但是最近学习文献的时候在核口的一些CFD代码文章比如SIMMER-III,AFDM,还有一些其他程序里出现了另外一种形式:
    $k=A+B*\left|U_c-U_d\right|$
    B项一般是跟$C_d$相关,在SIMMER-III中其形式为:
    $B=\frac{1}{8}a_i\rho_cC_D,a_i是交界面面积$
    而A项给出的解释一般是comes from Stokes law for viscous flow,形式一般是:
    $A=\frac{3\alpha_c\mu_c}{d_d}$
    比较好奇这种形式的曳力系数是怎么得到的,尤其是A项,在文献里也没看到相关的引用。
    是否是由于这些代码一般是用来计算液态金属-气体两相流,因此比较特殊呢?
    希望各位大佬不吝赐教,非常感谢!:xiexie:

  • 运算报错出现killed

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    @bestucan 谢谢老师,我试试

  • openfoam化学反应模拟如何导出组分的反应源项

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    W

    @江山不如凉竹 我就补充下求解器中保存组分的化学反应源项吧。
    不知道你用的什么chemistryModel。假设你用的是StandardChemistryModel,那就将StandardChemistryModel.C文件中下面代码里的NO_WRITE改成AUTO_WRITE,编译完成后算例再运行一步保存就可以了。

    // Create the fields for the chemistry sources forAll(RR_, fieldi) { RR_.set ( fieldi, new volScalarField::Internal ( IOobject ( "RR." + Y_[fieldi].name(), this->mesh().time().timeName(), this->mesh(), IOobject::NO_READ, //IOobject::NO_WRITE IOobject::AUTO_WRITE ), this->mesh(), dimensionedScalar(dimMass/dimVolume/dimTime, Zero) ) ); }

    注:要拷贝到自己的工程路径下修改编译,不建议直接在原始代码里改。

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    Unknown rhoReactionThermo type Valid rhoReactionThermo types :

  • ubuntu启动黑屏 - 独显问题

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    李东岳

    我们2020年发的服务器,有一些客户需要做ubuntu系统。当时我们给他们做的显卡驱动。但是这个显卡驱动经常出问题。就像啥的,就像写代码出来,总是有bug,需要经常维护。主要就是这个ubuntu内核总是自动更新。有时候还禁用不干净。所以我们2020年之后的机器,linux系统的,都不装显卡驱动。这个能装。但是客户如果没有自己维护的能力,每次找我们维护显卡驱动就太费事了。

    所以linux系统,如果需要装显卡驱动,请自己装然后自己维护(就是某一天开机黑屏了,要自己重新装一下)。

  • 最简单的提取openfoam边界名字的方法

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    李东岳

    foamDictionary constant/polyMesh/boundary -entry entry0 -keywords

    一行搞定。功能很强大。https://cpp.openfoam.org/v11/foamDictionary_8C.html

  • windows10 下载paraview5.11.2 无法使用

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    李东岳

    paraview5.11.2我前几天刚下载,再ubuntu打开没问题。我估计应该是你的电脑缺少点啥东西。看图跟opengl有关。具体不详

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    @strive_DUT 谢谢

  • 请教:OpenFOAM并行相关问题

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    G

    我最近也碰到这个问题,单核计算时对某个特定的patch上的面心可以赋值,但并行分块之后也是运行不了。

  • interFoam短周期波浪衰减过于严重

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    H

    Hi https://cfd-china.com/user/tidedrinker

    我在使用of2306也出现类似的情况,我的波频是1.3 而且不同网格密度的相位差和衰减率有明显差异

    但是我在使用最密网格(单位波高内20个网格)时,总是卡在67 迭代不出来 最终计算发散

    Courant Number mean: 1.18882076445e-06 max: 7.50119780436 Interface Courant Number mean: 3.00160678714e-08 max: 3.95428576669 deltaT = 6.18380398924e-152 Time = 67.132 PIMPLE: iteration 1 Updating StokesI wave model for patch inlet smoothSolver: Solving for alpha.water, Initial residual = 5.38442986655e-09, Final residual = 5.38442986655e-09, No Iterations 0 Phase-1 volume fraction = 0.666618301469 Min(alpha.water) = -2.29205431887e-10 Max(alpha.water) = 1.00000001308 MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.666618301469 Min(alpha.water) = -2.29205431887e-10 Max(alpha.water) = 1.00000001308 Updating shallowWaterAbsorption wave model for patch outlet DICPBiCGStab: Solving for p_rgh, Initial residual = 0.844109801632, Final residual = 0.00558442869736, No Iterations 20 DICPBiCGStab: Solving for p_rgh, Initial residual = 0.742328538632, Final residual = 0.00717435702295, No Iterations 26 time step continuity errors : sum local = 1.13821305653e-09, global = -5.40663033957e-10, cumulative = 2.0897431155e-05 DICPBiCGStab: Solving for p_rgh, Initial residual = 0.823953322827, Final residual = 0.00800680485496, No Iterations 25 DICPBiCGStab: Solving for p_rgh, Initial residual = 0.867377012998, Final residual = 9.38111948679e-10, No Iterations 389 time step continuity errors : sum local = 9.20755023008e-16, global = 7.16963646939e-16, cumulative = 2.08974311557e-05 smoothSolver: Solving for omega, Initial residual = 7.31631987399e-08, Final residual = 4.57762864183e-11, No Iterations 1 smoothSolver: Solving for k, Initial residual = 4.39226774226e-07, Final residual = 2.03583449134e-10, No Iterations 1 ExecutionTime = 29318.96 s ClockTime = 29376 s Courant Number mean: 1.18884127695e-06 max: 7.50169136387 Interface Courant Number mean: 3.0019195664e-08 max: 3.95459850554 deltaT = 8.24321301597e-153 Time = 67.132 PIMPLE: iteration 1 Updating StokesI wave model for patch inlet smoothSolver: Solving for alpha.water, Initial residual = 5.38393271075e-09, Final residual = 5.38393271075e-09, No Iterations 0 Phase-1 volume fraction = 0.666618301469 Min(alpha.water) = -2.29205431887e-10 Max(alpha.water) = 1.00000001308 MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.666618301469 Min(alpha.water) = -2.29205431887e-10 Max(alpha.water) = 1.00000001308 Updating shallowWaterAbsorption wave model for patch outlet DICPBiCGStab: Solving for p_rgh, Initial residual = 0.844175076514, Final residual = 0.00539645720402, No Iterations 20 DICPBiCGStab: Solving for p_rgh, Initial residual = 0.742024848316, Final residual = 0.00733560856723, No Iterations 27 time step continuity errors : sum local = 1.16277362766e-09, global = -5.78716682763e-10, cumulative = 2.08968524391e-05 DICPBiCGStab: Solving for p_rgh, Initial residual = 0.824114713535, Final residual = 0.00803020015335, No Iterations 25 DICPBiCGStab: Solving for p_rgh, Initial residual = 0.867366339743, Final residual = 9.11722968482e-10, No Iterations 373 time step continuity errors : sum local = 8.95106772158e-16, global = -5.97636368108e-16, cumulative = 2.08968524385e-05 smoothSolver: Solving for omega, Initial residual = 7.30573956466e-08, Final residual = 4.54407875238e-11, No Iterations 1 smoothSolver: Solving for k, Initial residual = 4.38607733913e-07, Final residual = 2.03320386843e-10, No Iterations 1 ExecutionTime = 29358.38 s ClockTime = 29416 s Courant Number mean: 1.18886725019e-06 max: 7.50212848379 Interface Courant Number mean: 3.00241095746e-08 max: 3.95487860459 deltaT = 1.09878323649e-153 Time = 67.132 PIMPLE: iteration 1 Updating StokesI wave model for patch inlet smoothSolver: Solving for alpha.water, Initial residual = 5.38400281089e-09, Final residual = 5.38400281089e-09, No Iterations 0 Phase-1 volume fraction = 0.666618301469 Min(alpha.water) = -2.29205431887e-10 Max(alpha.water) = 1.00000001308 MULES: Correcting alpha.water MULES: Correcting alpha.water Phase-1 volume fraction = 0.666618301469 Min(alpha.water) = -2.29205431887e-10 Max(alpha.water) = 1.00000001308 Updating shallowWaterAbsorption wave model for patch outlet -------------------------------------------------------------------------- Primary job terminated normally, but 1 process returned a non-zero exit code. Per user-direction, the job has been aborted. -------------------------------------------------------------------------- -------------------------------------------------------------------------- mpirun detected that one or more processes exited with non-zero status, thus causing the job to be terminated. The first process to do so was: Process name: [[8254,1],7] Exit code: 145 --------------------------------------------------------------------------

    在粗网格和中等网格却计算很稳定。根据https://cfd-china.com/topic/5462/mpirun-detected-that-one-or-more-processes-exited-with-non-zero-status,尝试修改了fvSolution,但依旧迭代不出来,请问您有什么解决办法吗