This is a general question. In my case, i am optimizing an FSAE diffuser. The two parameters are the entrance length (3 values) and the diffuser angle ( 4 values). What is the correct way to do this:

- optimize entrance length at a random fixed diffuser angle then optimize the diffuser angle at the highest performing entrance length. 3+4=7 simulations
- Simulate every combination of the two variables 3x4=12 simulations

The difference between the number of simulations of the two approaches increases quickly for a larger number of parameters.

Also , is 3 values enough to optimize a parameter?