1. A method of predicting deformation of a rocket nozzle due to rocket engine combustion products flowing through the rocket nozzle during times associated with engine start-up and engine shut-down, comprising the steps of: providing structural parameters describing the rocket nozzle and wall geometry thereof; providing flow properties generated by the rocket engine combustion products and entering the rocket nozzle during the times associated with engine start-up and engine shut-down; providing a processing system that includes at least one processor for implementing a plurality of programmed processing steps and at least one output device for presenting results generated by said programmed processing steps; said programmed processing steps including performing computational fluid dynamics (CFD) computations at time increments using said structural parameters and said flow properties wherein said CFD computations describe a flowfield associated with the rocket engine combustion products flowing through the rocket nozzle, wherein each of said CFD computations accounts for movement of the wall geometry of the rocket nozzle due to said flowfield, performing structural dynamics computations at each of said time increments using said CFD computations wherein said structural dynamics computations describe the movement of the wall geometry, and performing mesh dynamics computations at each of said time increments to redefine said flowfield to account for the movement of the wall geometry, said mesh dynamics computations being based on a spring analogy process; and outputting results of said programmed processing steps for at least one of said time increments using said at least one output device.