I have worked in the CFD area for almost 30 years and have used a number of the commercial packages. I am currently using ANSYS/CFX and am biased, but I do believe that it offers the best integrated solution available today.
I'm familiar with CFX and I believe you can use it to model water hammer. Water hammer is of course a pressure wave. In most situations water is treated as an incompressiblle fluid which implies infinite sound speeds. To model water hammer, you would have to treat the water as being compressible...
I am quite familiar with CFD and have quite a bit of experience with convergence of software like CFDesign and I've seen this question come up numerous times. I would suggest that you monitor the convergence of the quantity that you are primarily interested in. For example, if it's the total...