This paper introduces a virtual boundary method for compressible viscous fluid flow that is capable of accurately representing moving bodies in flow and aeroacoustic simulations. The method is the compressible extension of the boundary data immersion method (BDIM, Maertens & Weymouth (2015)). The BDIM equations for the compressible Navier-Stokes equations are derived and the accuracy of the method for the hydrodynamic representation of solid bodies is demonstrated with challenging test cases, including a fully turbulent boundary layer flow and a supersonic instability wave. In addition we show that the compressible BDIM is able to accurately represent noise radiation from moving bodies and flow induced noise generation without any penalty in allowable time step.
Direct numerical simulations (DNS) of boundary layers convecting over a compliant trailing edge are considered in this study. To that end a fully coupled fluid structure interaction framework was developed by coupling a newly developed structural solver to a well validated DNS code. The moving boundaries were represented by an immersed boundary technique using feedback-forcing which was validated with laminar boundary layer instability growth rates and a trailing edge noise problem. First results indicate that the compliant trailing edge yields a decreased noise level in the low and intermediate frequency range. In contrast to that an increased sound level has been found in frequency ranges close to the first three natural frequencies of the structure vibration.
In this work, a series of direct numerical simulations are conducted to study the effect of wall normal spanwise homogeneous wall actuation on a turbulent boundary layer. The moving boundary is represented by a boundary data immersion technique. A parametric study was performed, varying the actuator length, the wall normal actuation amplitude and the actuation frequency. It was found that localized actuation, relying only on wall motion instead of requiring a plenum in the case of synthetic jets, generated a net momentum flux jet affecting the flow not only in the immediate vicinity of the actuator but also for a significant distance downstream. The cases with an actuator velocity of u + act = 20.1 showed a particularly pronounced effect on the boundary layer and resulted in a recirculation region.
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