The decision to apply a wind code or CFD (Computational Fluid Dynamics) modeling will depend on the purpose and scope of the project in question.
If the objective is to perform wind analysis at the macroscopic level, i.e. to evaluate the effects of wind on large structures such as buildings, bridges or wind energy towers, then a wind code may be sufficient. Wind codes are simplified tools that allow the simulation of airflow around large, bulky structures and provide a general understanding of how wind affects the performance and safety of such structures.
On the other hand, if a more detailed and accurate analysis of airflow is required, such as in the design of an automobile, aircraft, or the analysis of the aerodynamics of a small object, then CFD modeling is recommended. CFD models are capable of simulating airflow around complex and detailed objects, allowing a much deeper understanding of the physical phenomena involved in airflow.