瞬时边界条件设置 请求高手指点

花花123

我在帮助文件里看到下面的UDF，有些问题不太明白，
This UDF is used to provide a time-varying specification of the mass flow rate. This boundary condition can be applied using a DEFINE_PROFILE UDF. The following UDF, named inlet_mf, adjusts the mass flow rate from  $1.00 kg/s$ to  $1.35 kg/s$ when the physical time step is greater than  $0.2$ seconds. After it has been interpreted or compiled, you can activate this UDF in the Mass-Flow Inlet boundary condition dialog box in ANSYS FLUENT by selecting the UDF from the Mass Flow Rate drop-down list.
#include "udf.h"

DEFINE_PROFILE(inlet_mf,th,i)
{
   face_t f;
   begin_f_loop(f,th)
     {
       if(CURRENT_TIME <= 0.01)
          F_PROFILE(f,th,i) = 3.0;
       else if(CURRENT_TIME <=0.02 && CURRENT_TIME >0.01)
          F_PROFILE(f,th,i) = 4.0;
       else
          F_PROFILE(f,th,i) = 5.0;
     }
    end_f_loop(f,th);
}
为什么UFD中没有出现1.35和1，出现的3.0,  4.0,   5.0是什么意思