CFD中文网

请教一下，我想研究不同风向对建筑物风环境的影响，比如有八个风向，但是只生成一次网格。用一个圆柱体定义一个cellZone，里面包含所有建筑物体，然后每模拟一个风向后，将cellZone 转动一个角度，即建筑物转动一个角度，接着模拟下一个风向。用的求解器是SimpleFoam.
我在网上找到有关吊扇的案例，但是风扇是通过dynamicMeshDict设置的周期性转动的，且用的是PimpleFoam。
https://www.openfoam.com/documentation/guides/latest/doc/tutorial-pimplefoam-ami-rotating-fan.html

是否有命令可以简单的转动cellZone一个角度，来满足只生成一次网格的想法？
谢谢指点！

请问各位大神，SHM里哪个参数导致生成的网格如图所示的拉伸变形？多谢！

@东岳 多谢！找到了！！

请问如何显示3D剖面，如图所示？
多谢！！

我试着安装openfoam在win10系统上，用的下面这个链接提供的安装文件。
https://www.openfoam.com/download/release-history.php
之前安装过，上半年还还好用的。但有一次系统更新后，Virtualbox就打不开了。
我重新安装时，过程中就显示以下信息，无论如何也不能安装成功。有哪位大神可以指点迷津吗？多谢！

Set-ExecutionPolicy : Windows PowerShell updated your execution policy successfully, but the setting is overridden by
a policy defined at a more specific scope.  Due to the override, your shell will retain its current effective
execution policy of Bypass. Type "Get-ExecutionPolicy -List" to view your execution policy settings. For more
information please see "Get-Help Set-ExecutionPolicy".
At C:\Program Files (x86)\ESI\OpenFOAM\1706\Windows\Scripts\of_install_image.ps1:2 char:1
+ Set-ExecutionPolicy Unrestricted -Scope CurrentUser
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : PermissionDenied: (:) [Set-ExecutionPolicy], SecurityException
    + FullyQualifiedErrorId : ExecutionPolicyOverride,Microsoft.PowerShell.Commands.SetExecutionPolicyCommand
Num Args: 2
of_v1706_centos73.tar
C:\Program Files\Docker Toolbox\;C:\Program Files\Git\bin
Creating CA: C:\Users\gwu\.docker\machine\certs\ca.pem
Creating client certificate: C:\Users\gwu\.docker\machine\certs\cert.pem
Running pre-create checks...
(default) Default Boot2Docker ISO is out-of-date, downloading the latest release...
(default) Latest release for github.com/boot2docker/boot2docker is v17.11.0-ce
(default) Downloading C:\Users\gwu\.docker\machine\cache\boot2docker.iso from https://github.com/boot2docker/boot2docker/releases/download/v17.11.0-ce/boot2docker.iso...
(default) 0%....10%....20%....30%....40%....50%....60%....70%....80%....90%....100%
Creating machine...
(default) Copying C:\Users\gwu\.docker\machine\cache\boot2docker.iso to C:\Users\gwu\.docker\machine\machines\default\boot2docker.iso...
(default) Creating VirtualBox VM...
(default) Creating SSH key...
(default) Starting the VM...
(default) Check network to re-create if needed...
(default) Windows might ask for the permission to create a network adapter. Sometimes, such confirmation window is minimized in the taskbar.
(default) Found a new host-only adapter: "VirtualBox Host-Only Ethernet Adapter #6"
(default) Windows might ask for the permission to configure a network adapter. Sometimes, such confirmation window is minimized in the taskbar.
Error creating machine: Error in driver during machine creation: Unable to start the VM: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe startvm default --type headless failed:
VBoxManage.exe: error: The virtual machine 'default' has terminated unexpectedly during startup with exit code 1 (0x1).  More details may be available in 'C:\Users\gwu\.docker\machine\machines\default\default\Logs\VBoxHardening.log'
VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component MachineWrap, interface IMachine

Error checking TLS connection: Host is not running
Starting "default"...
(default) Check network to re-create if needed...
Unable to start the VM: C:\Program Files\Oracle\VirtualBox\VBoxManage.exe startvm default --type headless failed:
VBoxManage.exe: error: The virtual machine 'default' has terminated unexpectedly during startup with exit code 1 (0x1).  More details may be available in 'C:\Users\gwu\.docker\machine\machines\default\default\Logs\VBoxHardening.log'
VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component MachineWrap, interface IMachine
 ************************************************************************.
Welcome to the OpenFOAM  Windows Version (v1706)
Please do not close the windows. This step will install OpenFOAM image
and will take time depending on your system memory
It could take 10-15 minutes if system has 4 GB of RAM
 ***************************************************************************.
 of_v1706_centos73.tar
 image loading . Please Wait.......
error during connect: Post http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.29/images/load?quiet=0: open //./pipe/docker_engine: The system cannot find the file specified. In the default daemon configuration on Windows, the docker client must be run elevated to connect. This error may also indicate that the docker daemon is not running.
      Done loading the image. Waiting for final check.. ..
  Please wait.... Almost done.. This step will take approximately 1-2 minutes to complete

@yp http://dyfluid.com ，这里的内容很丰富。还有他们的公众号"CFD界"，也值得关注。

@李东岳 十分感谢方向指引！我会继续努力！:sunglasses:

@李东岳 CFD就是一部大片呗，迭中迭。simpleFoam就是第一部。
我还是得多补点基础。多谢东岳指教！
另外很感激你们翻译的openFoam用户手册。我只有一些高数和线性代数的基础，CFD从零开始直接看英文的手册，实在是很难懂在说什么。看了你们翻译过的，加上东岳流体的一些文章，才逐渐隐约看到了CFD的轮廓。
路漫漫，不过有你们在，希望能坚持下去。

@wwzhao 那就是都一样的。如果用pimpleFoam是不是差别只在于deltaT需要计算，给一个合理的值，其他求解过程都一样？

@random_ran 能花时间写这么多已经很感谢了！
我刚接触的CFD，其实本来不太纠结瞬态稳态问题，目前稳态求解对我要研究的东西够用的。只是这两天发现simpleFoam的每个时间步长里的所有物理量都有个No Iteration，突然困惑了，难道稳态也要每步都收敛？之前看过一些文章，一直理解为时间步长内收敛是瞬态特有的，现在又蒙了...

多谢大神的解释！
关于time step continuity errors没太懂，等我补点基础知识再来讨教。

不过不好意思，还有问题。瞬态求解和稳态求解的迭代运算有什么不同。
之前看过一篇文章强调说"瞬态计算要求在每个时间步内达到收敛。若不能达到收敛，则迭代次数达到所设定的内迭代次数后进入下一个时间步，重新开启迭代计算。" 所以瞬态计算的残差监视图是锯齿状的。而稳态的曲线一般相对"平滑"。
在苏伟军博客里看的有关simpleFoam的文章，他说"这里的endTime不再是求解结束时间，而是最大迭代次数有关的量（迭代次数=（endTime-startTime）/deltaT)。如果在设定的最大迭代次数内方程收敛，程序也会自动退出计算。"
这些听起来好像稳态求解的内迭代没什么大关系。这让我有些困惑，稳态也要求在每个时间步内达到迭代吧，有什么不同呢？

多谢多谢！我大概明白什么意思了。
譬如在fvSolution中的速度场里，设定reTol为0.1,则当Final residual与Initial residual的比小于等于0.1时，这个物理量在内循环中停止迭代。
如果残差小于tolerance，则这个物理量无论是在内循化还是外循化都不再进行迭代计算。
如果所有物理量的残差都满足residualControl中设定的值，则求解器停止计算，或者是超过endTime时求解器也停止计算。
以上理解正确吗？

再问一下，为什么会出现这个error: "time step continuity errors : sum local = 8.135033e-09, global = 8.232192e-10, cumulative = -4.119173e-06"
对计算结果影响大吗？

    U
    {

        relTol		0.1;

        tolerance		1e-8;

        nSweeps		1;

        smoother		GaussSeidel;

        solver		smoothSolver;

    }

SIMPLE
{

    nNonOrthogonalCorrectors		2;

    residualControl
    {

        k		0.0001;

        U		0.0001;

        epsilon		0.0001;

        p		0.0001;

    }

}

如果deltaT为1的话，不同于瞬态求解器，simpleFoam里的endTime是最大迭代次数，这样理解正确吗？
下面的是我在模拟结束后从simpleFoam.log里提取的一段，如果Time=200是第200次迭代，那这里的No Iterations是指什么？
顺便问一下ExecutionTime和ClockTime的区别是什么？
不好意思，刚接触CFD，问得都是小白问题。

Time = 200

smoothSolver:  Solving for Ux, Initial residual = 0.0006172735, Final residual = 3.130585e-05, No Iterations 3
smoothSolver:  Solving for Uy, Initial residual = 0.0006120918, Final residual = 3.047995e-05, No Iterations 3
smoothSolver:  Solving for Uz, Initial residual = 0.00992249, Final residual = 0.0005011013, No Iterations 3
GAMG:  Solving for p, Initial residual = 0.0138261, Final residual = 0.0006013534, No Iterations 2
GAMG:  Solving for p, Initial residual = 0.001282478, Final residual = 0.0001129397, No Iterations 2
GAMG:  Solving for p, Initial residual = 0.0002430735, Final residual = 1.691212e-05, No Iterations 3
time step continuity errors : sum local = 8.135033e-09, global = 8.232192e-10, cumulative = -4.119173e-06
smoothSolver:  Solving for epsilon, Initial residual = 0.0003394608, Final residual = 2.162896e-05, No Iterations 3
smoothSolver:  Solving for k, Initial residual = 0.004169046, Final residual = 0.0002986839, No Iterations 3
ExecutionTime = 2357.53 s  ClockTime = 2430 s