massless particle tracking problem
 

Hi guys,

I am simulating a 2D transient flow and want to track the trajactory of a fluid element in the flow. So I am using the unsteady tracking with a massless particle. I chose the Track with Fluid Flow Time option and set the Max number of steps to 5e7. I thought for this option the integral time for the particle tracking is equal to the time step size of the continous phase flow. However, I found the result of the unsteady tracking is not what I want. I did an unsteady tracking when the continous phase flow ran for one time step, and did a steady tracking at this time step. I found that the location of the particle from the unsteady tracking is the same as the final location from the steady tracking. So I wonder how to control the integral time for the unsteady tracking so that it is equal to the time step size of the continous flow. Thank you.

Renold