Noise generated by turbulent flow over forward facing steps

In this study, aeroacoustical characteristics of forward facing steps (FFSs) subject to turbulent freestream are assessed by means of linearized Euler equations (LEE). The investigated parameters are the velocity scaling of SPL and the different construction of sharp edge of FFSs. In addition to numerical simulation, an analytical vortex injection method and flow measurement are also utilized for validation purposes. It is found that the sound signal obtained from the simulation and from the theoretical approach at prescribed positions are of same phases and have comparable amplitudes. Moreover, it is reported that sound intensity scales with 5.8th power of freestream velocity. This result agrees well with the theoretical result of Curle et al. Sound radiation pattern is found to have dipole character lying horizontally. Finally, it is shown that one gains ≈10–15dB reduction in SPL by replacing sharp edged FFS with the half round edged one. Furthermore, round edged FFS, i.e. r=hr=h, is ≈4–5dB more silent than half round edged FFS at the same frequency level.