### 6.2.3. User Errors

User errors result from the inadequate use of the resources available for a CFD simulation. The resources are given by:

- Problem description

- Computing power

- CFD software

- Physical models in the software

- Project time frame.

According to the ERCOFTAC Best Practice Guidelines [140], some of the sources for user errors are:

- Lack of experience

- Lack of attention to detail or other mistakes.

Often, user errors are related to management errors when insufficient resources are assigned to a project, or inexperienced users are given a too complex application. Typical user errors are:

- Oversimplification of a given problem; for example, geometry, equation system, and so on

- Poor geometry and grid generation

- Use of incorrect boundary conditions

- Selection of non-optimal physical models

- Incorrect or inadequate solver parameters; for example, timestep, and so on

- Acceptance of non-converged solutions

- Postprocessing errors.

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