Planar velocity and scalar concentration measurements in shock-accelerated,unstable fluid interfaces.
- Cherie
- Sanjay
- Mark
- Adam
- Katherine P.
- Paul M.
- Chris D.
- Michael T.
- James R.
- Cindy A.
- Greg
- Peter V.
We report applications of several high-speed photographic techniques to diagnose fluid instability and the onset of turbulence in an ongoing experimental study of the evolution of shock-accelerated, heavy-gas cylinders. Results are at Reynolds numbers well above that associated with the turbulent and mixing transitions. Recent developments in diagnostics enable high-resolution, planar (2D) measurements of velocity fields (using particle image velocimetry, or PIV) and scalar concentration (using planar laser-induced fluorescence, or PLIF). The purpose of this work is to understand the basic science of complex, shock-driven flows and to provide high-quality data for code validation and development. The combination of these high-speed optical methods, PIV and PLIF, is setting a new standard in validating large codes for fluid simulations. The PIV velocity measurements provide quantitative evidence of transition to turbulence. In the PIV technique, a frame transfer camera with a 1 ms separation is used to image flows illuminated by two 10 ns laser pulses. Individual particles in a seeded flow are tracked from frame to frame to produce a velocity field. Dynamic PLIF measurements of the concentration field are high-resolution, quantitative dynamic data that reveal finely detailed structure at several instances after shock passage. These structures include those associated with the incipient secondary instability and late-time transition. Multiple instances of the flow are captured using a single frame Apogee camera and laser pulses with 140 {mu}s spacing. We describe tradeoffs of diagnostic instrumentation to provide PLIF images.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 977900
- Report Number(s):
- LA-UR-04-7243; TRN: US201012%%574
- Resource Relation:
- Journal Volume: 5580; Conference: Submitted to: Proceedings of the SPIE 26th International Congress on, High-Speed Photography and Photonics
- Country of Publication:
- United States
- Language:
- English
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