I have been following this thread the last few days and would like to chime in some. First, I would highly doubt that OpenFOAM is producing incorrect shear stress values as it has been used for many years in both academic and research projects. Something that basic would have been caught by the people using the code. I really need to revisit this problem again because it is a very important baseline simulation for the platform to have complete.
Dave, did you make sure to choose one of my simulations with the proper frontal area? One issue I did find was that the forces and coefficients would be incorrect if the proper area was not used with a symmetric simulation. This messed me up for a while and I don’t know if this exact simulation is correct.
Everyone, we really need to make a simulation profile with Cd versus Re with comparison to literature. This should be done at multiple rear hatch angles as this angle is very important regarding the final draft coefficient. I may have bit off more than I could chew at the time of the initial simulation. I have learned quite a bit from reading papers since then (specific to this problem) and should probably update the Ahmed Calculations.