Streaklines

Streaklines describe the motion of an injected mass less material at a specific point in a flow volume over a certain time interval. Therefore a Streakline is a family of line segments. The following class Streakline holds data of a single Streakline:

 

#CLASS StreakLine : Trace {
  int number_of_steps;
  int max_number_of_steps;
};

where number_of_points is the number of points in a single trace segments (the trace for a single particle, released at one instant in time). There are number_of_steps time intervals under consideration. This results in number_of_steps +1 single traces. A time cut of the streakline is a line build up by the corresponding cuts of the single traces. With increasing time its length grows first and then keeps at a certain length. A list of times gives the stored timecuts of a streakline. number_of_steps is assumed to be greater than number_of_points.

       ------------- time ---------->

       ------------------|-->
        -single trace ---|--->
         ----------------|---->
          ---------------|----->
           --------------|------>
            -------------|------->
             ------------|-------->
              -----------|--------->
               ----------|---------->
                         streakline

A streak time ruler in the moving projects allows to fix the length of the single traces, where the interval from start time to end time determines the total considered time interval. A button "move streaks" allows to release streaklines at picked positions.

   

GRAPE(streak, "display")()

STREAKLINE *streak

The method "display" visualizes the first trace in a streakline.

   

GRAPE(streak, "get-object")(triang1d,t)

STREAKLINE *streak
TRIANG1D *triang1d
double t

"get-object" returns a Triang1d instance containing the current time slice at time t.

       

GRAPE(streak, "list-alloc")(maxpoints,maxsteps)

GRAPE(streak, "list-free")()

STREAKLINE *streak
int maxpoints,maxsteps

"list-alloc" allocates memory for a maximum of maxpoints points in a single trace of the Streakline and maxsteps integrations intervals. This results in a maximum of maxsteps +1 such traces. "list-free" frees the memory in a Streakline. For more information about "list-alloc" and "list-free" see 5.4.4.2.

   

GRAPE(streak, "get-times")(stime,etime)

STREAKLINE *streak
double *stime,*etime

get-times fills stime, etime with the maximal and minimal time of a Streakline.