Investigative Research on the Effect of Zero-Mass Jets on the Base Drag of Axisymmatric Bodies at Sunersonic Speeds

摘要

Preliminary investigations of wakes behind bodies with a blunt base have been carried out. For low subsonic Mach numbers, we have found that zero- mass jets that are generated by high-frequency forcing can have a significant effect on the flow structures that develop downstream of the base. These investigations were carried out using Direct Numerical Simulations (DNS) based on the complete Navier-Stokes equations for compressible flows. The codes for these simulations were developed with previous funding from ARO and have been tested extensively and validated by numerous comparison calculations. In the simulations, the zero-mass jets were generated by high-frequency, periodic blowing and suction at the base. With funds from the present STIR grant, we wanted to confirm, validate, and extend our preliminary investigations on the effects of zero-mass jets on the wake structures behind an axisymmetric body with a blunt base. Of particular interest was the question if the numerical simulations of zero-mass jets could be extended to high subsonic and supersonic Mach numbers. Toward this end, our Navier-Stokes code, which was previously developed for investigating supersonic base flows, was modified to allow for the introduction of high-frequency disturbances at the base of the body.