One way multiphysics coupling within a transient simulation

Hello Fellow Users,

I am solving two physics (fluid flow & species transport) in a transient simulation. The fluid flow is not affected by the concentration distribution. As of now, i have implemented the above using 'fully coupled' feature.

Is there any way to implement one way coupling within a transient simulation i.e. at every time step i want to solve for fluid flow first and then use that estimated velocity field to calculate the concentration distribution. It is not clear to me whether segregated step would do the above mentioned? I tried segregated node separating these two physics (still using direct solver) for both physics but the total simulation time goes up (more than double) compared to the fully coupled case.

my understanding is : if segregated step implements one way coupling then the simulation time should be less than the fully coupled case? any thoughts/comments on this.

Any guidelines or similar example for this kind of coupling in dynamic simulation is appreciated.

Thanks in advance for your suggestions.