用瞬态方法求解DPM时出现报错！！求大神指点一下！！

zyj2020

在使用fluent的DDPM模型做仿真的时候，迭代没有几步就出现警告： 9.9650% of the total discrete phase mass was not tracked for the expected residence time:0.00028 s less on a mass-weighted average (which is 2.2752% of their total age or 28.0006% of the last time step).
You may be able to reduce this discrepancy by changing the tracking parameters, that is,increasing the maximum number of time steps used to compute a single particle trajectory.出现这个是什么原因啊，还有该怎么设置才可以？