Disclaimer I'm an applied mathematician by training, not an engineer. My work research primarily focuses on creating new "methods" to solve different PDE's related to solid deformation (elasticity) and fluid mechanics. In this sense, i know how to solve a pde problem computationally. From my perspective, engineers use my work as "tools" to accomplish their work.
However, due to my lack of education/experience in engineering, i admit i'm actually rather clueless on how numerical solutions to pde's are really used in an engineers actual practice. The primary source of my confusion is the following:
I've been told that engineers never (or should never) conduct numerical simulations (e.g. finite element analysis, CFD, etc...) without knowing or having a good idea ahead of time what the simulation "should" look like. This helps engineers discriminate realistic results from questionable ones.
However, i argue that if the engineer already knows what is supposed to happen in the simulation, then what's the point of simulation in the first place??? I've always assumed that simulations are needed for predictive purposes, which assumes ignorance of what is to come. That is, I think of a simulation as a stand-alone tool to predict the future when you don't know what to expect.
What i'm looking for is a broader perspective into how/when/why engineers use numerical simulations like CFD and Finite Element Analysis, especially if good engineering practice dictates that you should already know what to expect when you're simulating?