[Lee 小亢]

Hi everyone~
My UDS is a transient computation, I defined a scalar, then I defined the source term,convective term and diffusivity term for the scalar. In the starting a few seconds, the computation works well, but later on,the value becomes vary strange:the value of the scalar decreases significantly, even the value becomes negative value(as I expect the value of it should keep increasing, WHY???) I don't know how to upload the pictures. If anyone is intersted in or know how to deal with this, please contact me, I can give you the picture.
Thanks a lot~