On the near Flow Field Generated by the Supersonic Flow over Rearward Facing Steps

摘要

Measurements were made and evaluated in the oncoming boundary layer, in the free shear layer, the lip shock and in the wake (or reattachment) shock region. Pitot and static pressure surveys were conducted, along with hot wire measurements and flow visualization studies. The measured free shear layer profiles were compared at different free stream Mach numbers, Reynolds numbers and step heights. A new technique was established for reducing the hot wire data. This was based upon the heat transfer correlation formula, and allows a broader range of applicability; in both the low Reynolds number region and in the free shear layer where the flow field is changing rapidly. This technique when applied to the measurements allowed the flow structure in the recirculating region to be explored. The low base pressure generated by the step influences the flow field ahead of the step and the extent of this upstream influence has been discussed. A new base pressure correlation parameter has also been developed for fully laminar and transitional flow. (Author)