[mejahan]

Originally Posted by mejahan

Thank you Glenn,
I have tried a finer mesh over the interface, and results are the same with better contour color map for the residence time. I have also tried to reduce the element size of the entire domain, but I faced convergence difficulties showing the transient flow behavior. I need to mention that the flow is entirely laminar and steady state. This behavior is expected in turbulent flows where extremely fine mesh results in resolving small scale eddies.
I was thinking that this problem may arise from the effect of the neighboring elements with extremely different residence time values.
I am also trying another case with finer mesh at the interface.

Hi Glenn,

I have tried multiple cases with a fine mesh and 5-7 layers at the interface, double precision solver, high resolution advective scheme for this variable, and still have a distribution of the Residence time at the fresh flow region.
The only thing that comes to my mind is that since the flow is inherently diffusive, in addition to be advective, therefore, we observe the influence of the recirculation flow at the boundary of the fresh incoming flow. At the center of the fresh flow, the residence time is zero. Therefore, observing a distribution of residence time at the boundary of the fresh incoming flow seems unavoidable, although it is very small, i.e. <0.02 s.

In different note, I would like to acknowledge your advice in my future publication and would like to have your affiliation.

Thank you,
Mehdi

[ghorrocks]

Good to hear you got it working good enough in the end.

My name is Glenn Horrocks, I work for Memjet Australia.