could you attach a 2010 version of your file , i couldn't have a look.....
thanks in advance
Even if the solution converges, there's no guarantee that your model will be a good approximation of reality. Errors in boundary conditions or incorrect turbulence models, for example, can give you a solution that won't reflect reality. The best way is to start with a real life experiment and build your CFD model off that, so you can verify your solution. This type of exercise will build confidence and help you refine the type of analysis you do. Naturally you'll want to pick out experiments that are related to the problems you want to model.
-First of all how can you certify your results with Flow Simulation? Indeed I used to do some FEA analysis using the software Abaqus for example. In order to certify my results, I refine my meshing until I get the convergence of my Von Mises stress. It looks automatic with Solidworks, is it right? (or it's maybe why we define goals...)
same methods, improve the mesh, make sure convergence has been achieved, and check the setup as amit mentions.
-Is there any ways to calculate directly the drag coefficient and find the center of pressure?
there is no built in function to calculate the coefficients, but all the components are reportable. there is even a tutorial on this.
-Moreover my calculation looks really long... I attached the file if ever you can have a look... I need to find out about cavitation.
calculation is long and cavitation is enabled? this is expected. i would definitely start smaller, disable cavitation to start to get an understanding if what is going on, coarse mesh and then you can refine later.