Abstract
Molecular tagging velocimetry, a minimally intrusive laser diagnostic, was used to find quantitative off-body velocity measurements in the wake of both strut-mounted and free-flight spheres in hypersonic flow. Acetone gas seeded in the flow was excited using the fourth harmonic of a pulse-burst Nd:YAG laser. The experimental tests were validated and compared to simulations using a continuous Galerkin flow solver and an adaptive mesh refinement process. Near the centerline in the wake of the sphere, velocities between −105 and 65 m/s were observed due to reverse flow in the viscous shear layer. Similarly, the simulated data showed negative velocity values in the shear layer region. Outside of the shear layer, average velocities of 730 m/s were observed in both the experimental and simulated results. The overall average uncertainty for the strut-mounted and free-flight cases was estimated to have an accuracy of ±4% (±35.5 m/s or 4.9%). This non-intrusive technique provides a velocity map of the wake behind a sphere under hypersonic conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 1933-1942 |
| Number of pages | 10 |
| Journal | Applied Optics |
| Volume | 64 |
| Issue number | 8 |
| DOIs | |
| State | Published - Mar 10 2025 |
Funding
Oak Ridge National Laboratory (DE-AC05-00OR22725); National Aeronautics and Space Administration (80NSSC19M0194). The authors would like to thank Geneva Ballard, Andrew Cervantes, Patrick Hughes, and Rafael Lopez from the Hypersonics Laboratory at the University of Texas at San Antonio for their help in this study. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Oak Ridge National Laboratory, NASA, or the US Government.This paper has been authored by UT-Battelle, LLC, with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the paper for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this paper, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan