Liquid crystal coatings for surface shear stress visualization in hypersonic flows

Conference · Mon Jan 01 04:00:00 EST 1990

DOI:https://doi.org/10.2514/6.1990-1513· OSTI ID:6975863

Reda, D C; Aeschliman, D P

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 Labs., Albuquerque, NM (USA)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6975863
• Report Number(s): SAND-89-2389C; CONF-9006153--1; ON: DE90010846
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320201 -- Energy Conservation
Consumption
& Utilization-- Transportation-- Air & Aerospace
36 MATERIALS SCIENCE
360603* -- Materials-- Properties
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
440600 -- Optical Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
ADIABATIC PROCESSES
AERODYNAMICS
AIRFOILS
COATINGS
CRYSTALS
FEASIBILITY STUDIES
FLOW MODELS
FLUID FLOW
FLUID MECHANICS
FLUIDS
FUNCTIONS
HYPERSONIC FLOW
ISOTHERMAL PROCESSES
LIQUID CRYSTALS
LIQUIDS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
MECHANICS
OPTICAL PROPERTIES
PERFORMANCE TESTING
PHYSICAL PROPERTIES
PRESSURE EFFECTS
RESPONSE FUNCTIONS
SHEAR
STRESS ANALYSIS
SURFACE PROPERTIES
TEMPERATURE EFFECTS
TESTING
TURBULENT FLOW