Bad fire effects on rocket engine

I am trying to create an animation involving a rocket engine, which I am trying to get as physically realistic as I can. However, I can’t seem to get the fire to be smooth or create mach diamonds. In addition to that, the fire generated by particles goes right through my collision object. Firstly though I’d like to tackle the issue of the fire not being smooth. I have attached an image, let me know if you want the blend file.

nevermind about the smoothness I had to increase resolution;;

anybody got ideas on how the collision object doesn’t at all stop the fire from going through it?

Is it a smoke object of subtype ‘collision’, or an object with ‘Collision’ enabled?