Judging just from the animation you posted, I have a few comments:
1. Your jet seems to have an extremely low resolution mesh, it's obvious from the blending done by the "interpolate results" feature. There are large gradients across single cells, some of them appear to be as large as your jet nozzle diameter.
2. Since this software does not have the capability to do a moving mesh, it looks like you performed several simulations with the rocket at different distances from the "launch pad" and presented them as a single result in the animation, this is not intellectually honest.
Thank you for your observations!
In fact I think most of the blog participants, just like you, understand the actual functionality and capabilities of Flow Simulation.
The animation is simply one gif creation with images of scenarios. Simply wanted to share with all this excitement.
I had no interest here to create a validation study, only present the features and software interface. Anyway, I'm glad you observed carefully in my presentation, maybe you can share his extensive knowledge in CFD with us and informational materials.
I would be happy to read it
I think your presentation should show your mesh and how you chose the parameters such as cell size, local regions, etc... Getting a good mesh is one of the most critical parts of the simulation process.
If I was doing a simulation like this I would create an approximate jet volume where the expected high velocity gradients exist, and make sure to refine the mesh there sufficiently.
Also, the tip of your jet appears to land outside of the computational domain, you should allow plenty of room for the jet to dissipate within your domain for a more accurate model.