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Research and Development of High-performance Explosives
Published on: February 20, 2016
Raman spectroscopy of hypersonic shock waves
1Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid, Spain.
Summary
Raman spectroscopy effectively diagnoses hypersonic shock waves by measuring nitrogen density and rotational populations. This reveals molecular behavior analogous to helium shock waves, offering insights into high-speed gas dynamics.
Area of Science:
- Fluid dynamics
- Spectroscopy
- Physical chemistry
Background:
- Hypersonic shock waves present complex flow phenomena.
- Understanding molecular behavior in these regimes is crucial for aerospace applications.
- Raman spectroscopy offers a non-intrusive diagnostic tool.
Purpose of the Study:
- To utilize Raman spectroscopy for studying hypersonic shock waves.
- To measure density and rotational population profiles in nitrogen shock waves.
- To analyze molecular distribution functions and wake properties.
Main Methods:
- Generating normal shock waves in nitrogen (N2) within a free jet.
- Employing Raman spectroscopy to measure absolute density.
- Analyzing rotational population distributions across shock waves (Mach 7.7-15.3).
Main Results:
- Measured density and rotational population profiles across five normal shock waves.
- Observed a bimodal rotational distribution with scattered molecules, analogous to helium shock waves.
- Reported quantitative data on density profile invariance and wake properties.
Conclusions:
- Raman spectroscopy is an efficient diagnostic method for hypersonic shock waves.
- The study provides detailed molecular distribution data for nitrogen shock waves.
- Findings offer insights into gas dynamics at hypersonic speeds.
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