Liquid crystals for unsteady surface shear stress visualization

Conference · Fri Jan 01 00:00:00 EST 1988

OSTI ID:5025923

Reda, D C

Oscillating airfoil experiments were conducted to test the frequency response of thermochromic liquid crystal coatings to unsteady surface shear stresses under isothermal-flow conditions. The model was an NACA-0015 airfoil, exposed to an incompressible flow at a freestream Reynolds number (based on chord) of 1.14 x 10/sup 6/. Angle-of-attack forcing functions were sine waves of amplitude +- 10/degree/ about each of three mean angles of attack: 0/degree/, 10/degree/, and 20/degree/. Frequencies of oscillation were 0.2, 0.6 and 1.2 hertz, corresponding to reduced frequencies of 0.0055, 0.0164 and 0.0328. Data acquisition was accomplished by video recording. Observations showed the liquid crystal technique capable of visualizing high surface shear stress zones over the stated dynamic range in a continuous and reversible manner. 11 refs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5025923
• Report Number(s): SAND-88-1360C; CONF-880716-3; ON: DE88010570
• Resource Relation: Conference: 1. national fluid dynamics congress, Cincinnati, OH, USA, 24 Jul 1988
• Country of Publication: United States
• Language: English

Related Subjects

17 WIND ENERGY
LIQUID CRYSTALS
OPTICAL PROPERTIES
USES
STRESSES
MEASURING METHODS
TURBINE BLADES
MECHANICAL VIBRATIONS
WIND TURBINES
BOUNDARY LAYERS
SHEAR
CRYSTALS
FLUIDS
LAYERS
LIQUIDS
MACHINERY
PHYSICAL PROPERTIES
TURBINES
TURBOMACHINERY
170602* - Wind Energy Engineering- Turbine Design & Operation