Exit Boundary Layer Data for a Round Convergent Nozzle in Support of Numerical Simulation Efforts

An experiment is conducted with hot-wire anemometry to document the exit boundary layer characteristics of two nozzle configurations at jet Mach numbers up to 0.82. Far-field noise and jet plume experimental data from these two configurations have been used in Large Eddy Simulations (LES) of jets by colleagues at other Institutions. The current experiment provides the boundary layer data which have been identified as being critical for validation of the simulations since the initial conditions can significantly affect subsequent jet evolution and its radiated noise. The data exhibit fully turbulent boundary layers for the case with a pipe attached upstream of the nozzle. The case without the pipe involves ‘Blasius-like’ mean velocity profiles but a ‘highly disturbed laminar state’ with large turbulence intensities in a range of subsonic Mach numbers.