Software errors can be detected by verification studies. They are based on a systematic comparison of CFD results with verified solutions (in the optimal case analytical solutions). It is the task of the software developer to ensure the functionality of the software by systematic testing.
In most cases, pre-existing software will be used. It is assumed that all CFD packages have been sufficiently tested to ensure that no software verification studies have to be carried out in the project (except for newly developed modules). In case that two CFD packages give different results for the same application, using the same physical models, the sources for these differences will have to be evaluated. In case of code errors, they will be reported to the code developers and if possible removed.