STEADY AND UNSTEADY SURFACE PRESSURE DISTRIBUTIONS AROUND RECTANGULAR PRISMS WITH SHARP EDGES AT REYNOLDS NUMBER UP TO 2.5×10~6

摘要

The commonly-held assumption that the aerodynamics of rectangular prisms with sharp edges are insensitive to Reynolds number is shown to have limitations. Flow reattachment on the top and/or bottom of the prisms can be related to Reynolds number, Re. Steady and unsteady surface pressure measurements were carried out on nine different rectangular prisms for Re from 0.3 × 10~6 to 2.5 × 10~6 at several angles of attack, in smooth and turbulent flow. It was observed that the reattachment was dependent on parameters such as fineness ratio, edge treatment, angle of attack, turbulence of the oncoming flow and Reynolds number. Permanent reattachment occurred for prisms with fineness ratio of 4 and fluctuating reattachment took place for rectangular prisms with fineness ratio as low as 2.