Plug20 Test Report: Particle Image Velocimetry (PIV) Measurements

This report provides turbulent flow statistics made using particle image velocimetry (PIV) for several
internally mixed exhaust systems with external plugs (Plug20 designs). The tests were conducted at the
NASA Glenn Research Center’s Aero-Acoustic Propulsion Laboratory (AAPL) in May and June 2022.
The corresponding acoustic data for the configurations and flows presented in this report can be found in an earlier Technical Memorandum, NASA/TM-20210010291, “Plug20 Test Report.”

The Plug20 nozzle family was designed to represent commercial supersonic vehicles in the 2025 to
2035 timeframe with a bypass ratio around 4, having an internal mixer, with and without an external plug
to improve nacelle boattail drag and shock. The flow conditions measured represent engine cycles for
commercial supersonic aircraft at takeoff, having pressure ratios of 2.0 and heated fan and core streams, measured both with and without a flight stream surrounding the plume. A few unheated flow conditions were also tested to tie results to other baseline test results. The PIV measurements in both streamwise and cross-stream planes are described, along with brief analysis to visually catalog the contents and confirm their validity. In this analysis, the streamwise PIV is found to match benchmark datasets within its experimental error. However, the cross-stream turbulent quantities measured by two systems do not match each other or the streamwise measurements in amplitude—caution is required when using the cross-stream data.

Data acquired and included in this report are (1) velocity statistics of the plumes in both a streamwise
and several cross-stream planes, and (2) the hot nozzle geometry. Tabular forms of the data and
computer-aided design (CAD) files of the hot geometry are presented as supplemental files described in
Appendix A (TM-20230006779SUPPL1.zip) and Appendix B (TM-20230006779SUPPL2.zip).