CFD中文网

用的windAroundBuildings算例，840万网格的二维模型，网格质量检查过了，计算域是14000*4000米。epsilonInlet 0.0003; // Cmu^0.75 * k^1.5 / L ; L =10

dimensions [0 2 -3 0 0 0 0];

internalField uniform $epsilonInlet;

boundaryField
{
INLET
{
type fixedValue;
value uniform $epsilonInlet;
}

OUTLET { type zeroGradient; } WALL { type epsilonWallFunction; value uniform $epsilonInlet; } frontAndBackPlanes { type empty; } #includeEtc "caseDicts/setConstraintTypes"

}
kInlet 1.5; // approx k = 1.5*(I*U)^2 ; I = 0.1

dimensions [0 2 -2 0 0 0 0];

internalField uniform $kInlet;

boundaryField
{
INLET
{
type fixedValue;
value uniform $kInlet;
}
OUTLET
{
type zeroGradient;
}

WALL { type kqRWallFunction; value uniform $kInlet; } frontAndBackPlanes { type empty; } #includeEtc "caseDicts/setConstraintTypes"

}
nut
internalField uniform 0;

boundaryField
{
INLET
{
type calculated;
value uniform 0;
}

OUTLET { type calculated; value uniform 0; } WALL { type nutUSpaldingWallFunction; value uniform 0; } frontAndBackPlanes { type empty; } #includeEtc "caseDicts/setConstraintTypes"

}
p
internalField uniform 0;

boundaryField
{
INLET
{
type zeroGradient;
}
OUTLET
{
type fixedValue;
value uniform 0;
p0 uniform 0;
}
WALL
{
type zeroGradient;
}
frontAndBackPlanes
{
type empty;
}

#includeEtc "caseDicts/setConstraintTypes"

}
Uinlet (10 0 0);

dimensions [0 1 -1 0 0 0 0];

internalField uniform (10 0 0);

boundaryField
{
INLET
{
type fixedValue;
value uniform $Uinlet;
}
OUTLET
{
type zeroGradient;
}

WALL { type noSlip; } frontAndBackPlanes { type empty; } #includeEtc "caseDicts/setConstraintTypes"

}
时间步长试过1 0.1 0.01 其他的都没动

@东岳 刚性翼型用的pisoFoam，柔性翼型用的是fsiFoam。但是pisoFoam算出来的系数波动很大，而fsiFoam算出来系数波动就很小。不知道是为什么

看来还是有只用动网格而不用自适应的。这种状况应该用在变形的铁板、高层建筑随风摆之类的在一定范围内变形的。这样网格即使没有自适应也没关系。一般用来做应力分析之类的。

查看了下网格发现网格变形为负了

你的这个初始网格就不好。在圆形边界上没有用O形网格。畸变本就很严重，然后一变形，还不是震荡变形，是一直一个方向走，网格又没有自适应，然后就负网格了。

我同时想在INLET（火箭喷管口）设置燃气射流环境，目前改了 0/p 0/U 0/T 下的边界条件，并在constant/thermophysicalProperties 设置了燃气参数，但不知道如何指定在INLET上不断喷射燃气。

最简单的把边界设定成固定压力梯度。要是还要计算燃烧过程就不懂了:mihu:

钝体绕流来说，升阻力的主频和流场监测点的速度主频应该是相同的。

针对一个高度为3mm，宽度为1mm的矩形微通道，用fluent mesh 画网格后，在入口流速为0.3 0.4 m/s时，计算都可以收敛。但是当入口流速为0.5m/s时，计算收敛不了，这可能是什么原因导致的，尝试过增加网格数量也无效

已解决，虚拟机内存调到16g成功安装

@Cr 十分感谢，问题已经解决了:xinxin:

是的，@hangsz 说的第二种和行业关系很大。
就是在计算机行业也是如此，化工行业的CS说是待遇20万+也是普遍。

:sunglasses:

苹果retina屏那个本也不错。就是能不能装win系统？

http://item.jd.com/2819597.html

目前是在用重叠网格进行模拟，一个结构是固体，另一个是线弹性。用的是明渠造波，初始化总是崩溃，这是为什么呢？报错代码附在下面，感谢各位大佬抽出时间回答这个问题。
Grouping and repartitioning the fluid cell zones...

14 Stored Partitions:
P Cells I-Cells Cell Ratio Faces I-Faces Face Ratio Neighbors Load
0 52115 3581 0.069 176927 7246 0.041 5 1
1 52472 4620 0.088 162295 4236 0.026 4 1
2 54617 12093 0.221 134005 7412 0.055 9 1
3 52637 6006 0.114 169686 5664 0.033 4 1
4 52807 11023 0.209 167910 5289 0.031 6 1
5 52057 3479 0.067 162444 4597 0.028 5 1
6 52745 1693 0.032 170269 3362 0.020 2 1
7 52784 13211 0.250 163205 4296 0.026 5 1
8 52259 3566 0.068 176157 7128 0.040 5 1
9 51910 1672 0.032 160241 2070 0.013 1 1
10 51748 3480 0.067 164291 5004 0.030 3 1
11 54525 9324 0.171 134306 6166 0.046 8 1
12 51710 3562 0.069 166038 5640 0.034 4 1
13 54297 9707 0.179 133333 6836 0.051 9 1

Collective Partition Statistics: Minimum Maximum Total

Cell count 51710 54617 738683
Mean cell count deviation -2.0% 3.5%
Partition boundary cell count 1672 13211 87017
Partition boundary cell count ratio 3.2% 25.0% 11.8%

Face count 133333 176927 2200909
Mean face count deviation -16.7% 10.5%
Partition boundary face count 2070 7412 40198
Partition boundary face count ratio 1.3% 5.5% 1.8%

Partition neighbor count 1 9

Partition Method Metis
Stored Partition Count 14

Overset partition statistics:
P Cells Solve-cells Dead-cells
0 52115 58811 0
1 52472 52274 66
2 54617 56753 617
3 52637 54720 391
4 52807 46085 6296
5 52057 52626 0
6 52745 55832 0
7 52784 43070 6359
8 52259 58396 0
9 51910 51910 0
10 51748 53430 0
11 54525 59651 261
12 51710 54199 0
13 54297 58997 228

Overset Partition Statistics: Minimum Maximum Total

Cell count 51710 54617 738683
Mean cell count deviation -2.0% 3.5%

Solve cell count 43070 59651 756754
Mean solve cell count deviation -20.3% 10.4%

Dead cell count 0 6359 14218
Mean dead cell count deviation -100.0% 526.1%

Partition Method Metis
Stored Partition Count 14

Done.

10422 partition interfaces of the 215044 cells aspect ratio > 5 545456 groups for partitioning (including overlaps) Merging groups across partitions: 1 99888 2 8996 3 2718 4 599 5 112 6 20 7 2 8 0 Partition 535235 groups out of 738683 cells 183 partition interfaces of the 215044 cells aspect ratio > 5

Grouping and repartitioning the solid cell zones...

14 Stored Partitions:
P Cells I-Cells Cell Ratio Faces I-Faces Face Ratio Neighbors Load
0 3081 778 0.253 163329 1521 0.009 4 1
1 3081 814 0.264 163934 1432 0.009 5 1
2 3089 845 0.274 129565 7700 0.059 11 1
3 3076 819 0.266 164712 1583 0.010 3 1
4 3080 832 0.270 164935 1464 0.009 6 1
5 3079 829 0.269 162882 1455 0.009 6 1
6 3077 1026 0.333 163326 1996 0.012 7 1
7 3089 795 0.257 165081 1535 0.009 4 1
8 3092 928 0.300 163821 1637 0.010 5 1
9 3093 884 0.286 160599 1611 0.010 5 1
10 3090 761 0.246 161874 1493 0.009 4 1
11 3075 806 0.262 127548 7289 0.057 9 1
12 3097 868 0.280 162126 1544 0.010 5 1
13 3098 319 0.103 126305 4986 0.039 6 1

Collective Partition Statistics: Minimum Maximum Total

Cell count 3075 3098 43197
Mean cell count deviation -0.3% 0.4%
Partition boundary cell count 319 1026 11304
Partition boundary cell count ratio 10.3% 33.3% 26.2%

Face count 126305 165081 2133715
Mean face count deviation -18.9% 6.0%
Partition boundary face count 1432 7700 46322
Partition boundary face count ratio 0.9% 5.9% 2.2%

Partition neighbor count 3 11

Partition Method Metis
Stored Partition Count 14

Overset partition statistics:
P Cells Solve-cells Dead-cells
0 3081 55196 0
1 3081 55355 66
2 3089 54741 617
3 3076 54989 391
4 3080 47373 6296
5 3079 55136 0
6 3077 55822 0
7 3089 46159 6359
8 3092 55351 0
9 3093 55003 0
10 3090 54838 0
11 3075 56138 261
12 3097 54807 0
13 3098 55846 228

Overset Partition Statistics: Minimum Maximum Total

Cell count 3075 3098 43197
Mean cell count deviation -0.3% 0.4%

Solve cell count 46159 56138 756754
Mean solve cell count deviation -14.6% 3.9%

Dead cell count 0 6359 14218
Mean dead cell count deviation -100.0% 526.1%

Partition Method Metis
Stored Partition Count 14

Done.

42 partition interfaces of the 1073 cells aspect ratio > 5 43150 groups for partitioning (including overlaps) Merging groups across partitions: 1 6 2 0 Partition 43147 groups out of 43197 cells *** Subcommunicators recreated (11/14)! *** 565 partition interfaces of the 1073 cells aspect ratio > 5 Migrating partitions to compute-nodes.

Node 1: Process 14244: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 13: Process 4932: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 5: Process 7224: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 11: Process 8716: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 7: Process 6588: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 8: Process 5632: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 9: Process 7040: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 10: Process 3868: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 6: Process 4756: Received signal SIGSEGV.

==============================================================================

==============================================================================

Node 4: Process 820: Received signal SIGSEGV.

==============================================================================

===================================================================================
= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
= RANK 0 PID 13864 RUNNING AT DESKTOP-RDMJC80
= EXIT STATUS: -1 (ffffffff) ===================================================================================
= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
= RANK 2 PID 12200 RUNNING AT DESKTOP-RDMJC80
= EXIT STATUS: -1 (ffffffff)

The fl process could not be started.

@李东岳 在 求流体凝固为固体的算法 中说：

@北斗 最近在研究多孔介质。目前一种非常简单的凝固模型，就是利用多孔介质来处理。固体区域给定一个非常小的渗透率。

血小板聚集形成血栓

这种看起来像是拉格朗日粒子的黏连

请问李博士，您的意思是通过多孔介质来实现凝固吗，如何实现，这方面资料可以发出来吗

怎么能够对计算完的case设定单元区域，取得这个区域内自己想要的值

在破碎模型中，破碎的概率和子气泡分布一般涉及到积分式，比如说经典的Luo模型270626e3-d11f-4d47-a461-cdc3cbde1bb6-image.png 这里边openfoam官方直接用大佬提出来的化积分为多项式公式替代求解：e4c4c71f-d206-4464-bb15-5ee960dcdba8-image.png 有学者就提出来了这个exp内的判据不精准，使用表面能和韦伯数多重盘踞，然后这个积分式就这样了：
6f926600-85cf-4d78-a936-ef166ab439ab-image.png 现在这样的话积分还怎么求解呢，因为min和max函数的存在原来的积分式公式还能使用么。还是需要分段求积。原论文是植入到fluent中大佬没写怎么处理的.

在外加压力下（1.0 MPa）水进入螺旋文丘里管内，在喉部流速增大，压力降低，使液体组分中溶解空气的析出，不过由于喉部管径长度都远比空化管的大，所以压力降低至饱和蒸汽压以上。目前找到比较多空化的学习资料，但是这个由于压力没有降到饱和蒸汽压以下，所以溶解在水中的气体通过溶解气浓度差析出而不是空化的相变。网上找到的相关资料比较少，请问下有人知道这种情况在多相流模型这部分怎么设置吗（所用物理模型如图所示）。4944e90f4e8663cccb56c7acc73b26b.png

很遗憾，木有啊:sad:

fluent自定义过饱和函数时应该用那个压力数据来计算？我的静压只有不到100pa，太小了

@Cr 原来是在这里啊，感谢感谢！

@李东岳 确实

请问像这种狭窄处要划分边界层，怎样处理能保证网格高质量呢

文章题目为《The inviscid impingement of a jet with arbitrary velocity profile》，主要是分析了法向二维冲击射流流场的解析解，但是个人比较疑惑的是为什么控制方程只包括了压力的泊松方程（如下）而没有包括二维的欧拉方程？
d64e75d4-5884-42a4-b208-20c90325cc29-image.png

全文见附件，希望有朋友可以解答。The inviscid impingement of a jet with arbitrary velocity profile.pdf