Originally Posted by Gingervytes
No, it is not assumed -- it is observed and measured. The de Laval nozzle dates back to Victorian times, used in steam turbine engines. The pressure "gradient" is converted to velocity, which is expressed in your equation as Ve
I already pointed out that your derivation of the "pressure gradient force" was in error because you wrongly conflated two concepts in the derivation of the rocket equation. You did not address that. Before you claim that no one has refuted you, you must address the posts in which they do just that.