Grid generation is often quoted as the most important and most time consuming part of CFD analysis. The quality of the grid plays a direct role on the quality of the analysis, regardless of the flow solver used. Additionally, the solver will be more robust and efficient when using a well-constructed mesh. If there are some problems in selection and creation of mesh, this propagates all the way to the solution step and results into large amount of rework.
A good quality mesh is essentially an important input to the CFD solvers, which decides the convergence and accuracy of solutions.
Several parameters need to be considered before starting mesh generations. Few important parameters are like what type of mesh is required (Tetrahedral, Hexahedral, Hybrid mesh etc.) mesh quality, mesh distribution in the viscous and Inviscid regions, what type of boundary layer modelling will be employed in CFD solver (Anticipated y plus range), identifying high gradient regions and placing fine mesh resolutions etc.
This is possible only when a CFD expert is available to guide the meshing team. In our organizations we technically think beyond our customer expectations to provide the best solutions.