然后我打开了fluent残差的设置面板，默认设置为：

Convergence Criterion 里默认是 absolute，然后下拉菜单有;

而文章中所谓的 “the relative error between successive iterations” 到底属于absolute 还是 relative呢？
fluent用户手册里对两者的定义分别是：

absolute
is the default and is available for steady-state cases. The residual (scaled and/or normalized) of an equation at an iteration is compared with a user-specified value. If the residual is less than the user-specified value, that equation is deemed to have converged for a time step.
relative
is where the residual of an equation at an iteration of a time step is compared with the residual at the start of the time step. If the ratio of the two residuals is less than a user-specified value, that equation is deemed to have converged for a time step.

absolute是将该步计算所得值与给定值（初始化值？）进行比较所得的残差；relative是当前时间步长所得残差与初始时间步长所的残差的比较值。
那么文章中所指到底是哪种残差？还望各位大神不吝赐教~