Liquid crystal coatings for surface shear stress visualization in hypersonic flows
Experiments were conducted to test the surface-shear-stress visualization capabilities of shear-stress-sensitive/temperature- insensitive liquid crystal compounds in hypersonic flow. Liquid crystal coatings were applied to the surface of a conical model, which was then exposed to a high-unit-Reynolds-number (2.3 {times} 10{sup 7}/m) Mach 5 flow. The coating was illuminated by white light, and its response to the various flow situations was monitored and recorded with standard video and high-speed movie cameras. Boundary layer transition to turbulence was clearly demarcated by the technique. The dynamic location of the transition front as a function of model angle of attack (for sharp and blunt cones, with and without boundary-layer trips) was recorded, and observations were found to be consistent with established (published) trends for hypersonic flows over conical bodies. Normal shock passage over the model during tunnel shutdown was recorded (at 400 frames/second), and the liquid crystal coating was observed to respond to this event in a time interval less than or equal to the time between sequential movie frame exposures ({le} 0.0025 seconds). The liquid crystal technique has thus been demonstrated as a viable diagnostic tool for use in transient/compressible flows. 18 refs., 3 figs.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- DOE/DP
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6975863
- Report Number(s):
- SAND-89-2389C; CONF-9006153-1; ON: DE90010846
- Resource Relation:
- Conference: 21. AIAA fluid dynamics, plasmadynamics and laser conference in conjuction with the AIAA 25th thermophysics and heat transfer conference and the 16th aerodynamic ground testing conference, Seattle, WA (USA), 18-20 Jun 1990
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
47 OTHER INSTRUMENTATION
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
HYPERSONIC FLOW
FLOW MODELS
LIQUID CRYSTALS
AERODYNAMICS
ADIABATIC PROCESSES
AIRFOILS
COATINGS
FEASIBILITY STUDIES
ISOTHERMAL PROCESSES
MECHANICAL PROPERTIES
OPTICAL PROPERTIES
PERFORMANCE TESTING
PRESSURE EFFECTS
RESPONSE FUNCTIONS
SHEAR
STRESS ANALYSIS
SURFACE PROPERTIES
TEMPERATURE EFFECTS
TURBULENT FLOW
CRYSTALS
FLUID FLOW
FLUID MECHANICS
FLUIDS
FUNCTIONS
LIQUIDS
MATHEMATICAL MODELS
MECHANICS
PHYSICAL PROPERTIES
TESTING
360603* - Materials- Properties
420400 - Engineering- Heat Transfer & Fluid Flow
440600 - Optical Instrumentation- (1990-)
320201 - Energy Conservation
Consumption
& Utilization- Transportation- Air & Aerospace