High reynolds number flows: A challenge for experiment and simulation

Most available information on the behavior of turbulent flows has been obtained using small-scale facilites and limited computer resources. Consequently, the range of Reynolds numbers over which detailed data are available is limited, and in the case of large vehicles such as aircraft and submarines, several orders of magnitude smaller than that, experienced in practice. This disparity in Reynolds number places a great emphasis on scaling laws since the variation with Reynolds number must be known very accurately before predictions of the full-scale performance can be made with confidence. In many instances, we do not know the scaling laws with sufficient precision to make acceptable predictions, and further research is required. In this paper: we discuss the uncertainties in scaling laws as we understand them at present, and suggest a number of new experiments that will shed light on this subject.