可压流计算发散，出现Negative Initial Temperature 问题如何处理？
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@RebelYoung
你这个log是rhoC的吧？你的case是inviscid还是viscous flow? rhoCentralFoam对待inviscid flow是用的explicit方法求解，所以假如你没有viscosity，用diagonal solver时，residual就是0. -
@RebelYoung
建议先查boundary conditions；还有mesh，你的checkMesh结果呢 -
以上基本描述的都是rhoCentralFoam问题，报错是Negative Initial Temperature，但是全场最小温度并没有负值。。
这个rcf_sphere_laminar是根据，$FOAM_TUTORIALS/compressible/rhoCentralFoam/obliqueShock改的。是层流计算，/0下设置了p，T，U三个量。
以下贴出rhoC 0下文件：
./0/pFoamFile { version 2.0; format ascii; class volScalarField; object p; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [1 -1 -2 0 0 0 0]; internalField uniform 100000; boundaryField { ball { type zeroGradient; } inlet { type zeroGradient; } outlet { type fixedValue; value uniform 100000; } far { type zeroGradient; } }./0/T
FoamFile { version 2.0; format ascii; class volScalarField; object T; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 0 0 1 0 0 0]; internalField uniform 270; boundaryField { ball { type zeroGradient; } inlet { type fixedValue; value uniform 270; } outlet { type zeroGradient; } far { type fixedValue; value uniform 270; } }./0/U
其中U从1到250，都算过。都出现能量方程发散或negative initial temperature问题。FoamFile { version 2.0; format ascii; class volVectorField; object U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 1 -1 0 0 0 0]; internalField uniform (1 0 0); boundaryField { ball { type noSlip; } inlet { type fixedValue; value uniform (1 0 0); } outlet { type zeroGradient; } far { type fixedValue; value uniform (1 0 0); } }checkMesh结果：
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // Create time Create polyMesh for time = 0 Time = 0 Mesh stats points: 28680 faces: 309924 internal faces: 293684 cells: 150902 faces per cell: 4 boundary patches: 4 point zones: 0 face zones: 0 cell zones: 0 Overall number of cells of each type: hexahedra: 0 prisms: 0 wedges: 0 pyramids: 0 tet wedges: 0 tetrahedra: 150902 polyhedra: 0 Checking topology... Boundary definition OK. Cell to face addressing OK. Point usage OK. Upper triangular ordering OK. Face vertices OK. Number of regions: 1 (OK). Checking patch topology for multiply connected surfaces... Patch Faces Points Surface topology ball 9780 4892 ok (closed singly connected) far 4404 2278 ok (non-closed singly connected) inlet 1028 553 ok (non-closed singly connected) outlet 1028 553 ok (non-closed singly connected) Checking geometry... Overall domain bounding box (-0.1 -0.1 -0.1) (0.1 0.1 0.1) Mesh has 3 geometric (non-empty/wedge) directions (1 1 1) Mesh has 3 solution (non-empty) directions (1 1 1) Boundary openness (1.54762e-16 -1.49987e-17 -1.09064e-16) OK. Max cell openness = 3.03063e-16 OK. Max aspect ratio = 5.29154 OK. Minimum face area = 3.38388e-08. Maximum face area = 0.000137468. Face area magnitudes OK. Min volume = 4.46514e-12. Max volume = 4.98913e-07. Total volume = 0.00799582. Cell volumes OK. Mesh non-orthogonality Max: 58.0988 average: 22.4508 Non-orthogonality check OK. Face pyramids OK. Max skewness = 0.67456 OK. Coupled point location match (average 0) OK. Mesh OK. End./constant/thermophysicalProperties: 此文件根据rhoS中计算翼型的文件修改，因为原算例是想控制mach数等原因，改的不符合物理性质，且mu=0。我将其改成了正常参数。
FoamFile { version 2.0; format ascii; class dictionary; location "constant"; object thermophysicalProperties; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // thermoType { type hePsiThermo; mixture pureMixture; transport const; thermo hConst; equationOfState perfectGas; specie specie; energy sensibleInternalEnergy; } mixture { // normalised gas specie { molWeight 28.9; } thermodynamics { Cp 1005; Hf 0; } transport { mu 1.8e-5; Pr 0.71; } }FoamFile { version 2.0; format ascii; class dictionary; location "constant"; object turbulenceProperties; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // simulationType laminar; -
最新看到的说法是，T估算值或者插值中出现了问题。比如方程解的是h，那么从h=cp(T)T中解出T的估算值，结果是负的。。
rhoC解的是e，那么e=CvT，cv基本不变，那应该是e出现负值导致T出现负值。。。 -
@RebelYoung 出现负值不代表计算结果是负的。数值溢出也会成负值。就是大到极限了。
温度的 min max 最后一步最大值不但跳增，而且离上一个坐标点很远，这很明显有问题啊。一个时间步至少增长了4000K，你的时间步还那么的小。这种增长率很可能是数值溢出了。
如果问题描述搭的附件太多，会看起来很难成一体，即使尽力地暗逻辑描述。一般这种状况的信息是像引用文献那样表述的。下面是个例子，自由软件基金会的公开邮件。不过因为是纯文本格式的，所以网址是直接贴的，你可以用超链接。
这样主体信息和逻辑就不会被附件打断了。现在看你的帖子有种听微信语音的感觉
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