Learning Forum

[scabo]

Hi-

I have read the User guide. There are 2 things: In the main discrete dialogue box, there is an option for particle time step size. It is to inject particles in domain. Does it also control the particle trajectory integration size? There is another option to set length scale and step length factor in Tracking Parameter box. In user guide, it is mentioned that this controls the trajectory integration size. So is the first one only to inject particles in the domain? This is slightly confusing as the term particle time step size is used in both the cases. Any clarification is helpful, thanks.

[Rob]

Time step controls the injection but also how long to track each cycle of particle updates. The max steps, step length factor etc is then how many integration steps are done during the time step. So incomplete tracks can be due to too long a time step relative to the number of max steps or step length factor. 

[scabo]

So you are saying for each particle time step, there are these max no of steps and step length factor? But the particle integration time step size is controlled by step length factor right?(length/particle velocity)?

[Rob]

Probably.