⼀、变量未定义：CFLCMP
通过全局搜索我们可以发现，在层流的⽅程视图中⽤CFLCMP来定义CFL数。这么看来CFL数是内置变量。
查阅⽤户⼿册我们会到以下描述。
If the automatic expression for CFLloc is set to the built-in variable CFLCMP, then the
automatic setting suggests a PID regulator for the pseudo time step in the default热解气化
solver. The PID regulator starts with a small CFL number and increases CFLloc as the
solution comes closer to convergence.
CFLCMP明明是内置变量，只要勾选伪时间步进就会⾃动添加。 但是我们在优化求解器的分离项中可以查看到伪时间步进已经被激活，赋值处于⾃动状态。 继续查阅comsol的讨论我们发现已经有⼈遇到了相似的问题。他给出了⼀个不怎么靠谱的解决⽅案：
I found that ‘comp1.spf.locCFL’ is the pseudo time defined in Laminar flow. By default, in laminar flow-advanced setting, the box for ‘use pseudo time stepping for stationary equation form’ is checked, and CFL number expression is given automatically. However, it seems my CFL number wasn’t given automatically. So I just tick off the ‘use pseudo time stepping for stationary equation form’, then, it runs well.
However, I still don’t know why stationary study can run well while optimization can not previously.
删除求解器配置然后重新获取初始值求解，亲测⽆效。
在评论中有⼈给出了更⾼级的⽅案可惜我看不懂。
Open the .java, for example with eclipse. Search the line in which the study step is defined for the third solver
model.sol(“sol1”).feature(“st3”).set(“studystep”, “stat2”);
change it to李宝健
model.sol(“sol1”).feature(“st3”).set(“studystep”, “stat”);
Now the first step get´s simulated several times. Changes in the boundary conditions are not possible, but it fit´s at least for my case. save the .java file, when the automatic builder is activated, a .class file will be generated in the folder “bin”.
Open the .class file with comsol. With no further changes, the simulation starts automatically, so the opening process could last pretty long.
Would be nice to hear from some with more knowledge about comsol than me, why this work-around works, while taking stat2 as study step causes errors. I checked every line of the Java code, both steps were completly identical.
黑龙江经济报
或许我们可以⼿动设置CFLCMP，在层流⾼级选项中将伪时间步进下的赋值改为⼿动但是CFLloc的值保持默认。再次求解时，相同的错误不再出现。
⼆、⼴义源项的物理意义院星航
在⼆维流体传热物理场中添加域热源，其中⼴义源项的单位是W/m^3。⼀般⽤来近似⼴泛分布的化学反应，流固热耦合的拓扑优化。Select the General source (default) or Heat rate button to define Qs.
· For General source enter a value or expression for Qs as a heat source per volume.
交通参与者
· For Heat rate define the heat rate Ps. In this case Qs = Ps ⁄ V where V equal to the
volume of the layer selection.
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