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Visualization of Turbulent Wedges under Favorable Pressure Gradients Using Shear‐Sensitive and Temperature‐Sensitive Liquid Crystals
Author(s) -
CHONG TZEPEI,
ZHONG SHAN,
HODSON HOWARD P.
Publication year - 2002
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2002.tb04558.x
Subject(s) - pressure gradient , turbulence , temperature gradient , materials science , mechanics , shear (geology) , thermal , heat transfer , surface finish , chemistry , thermodynamics , composite material , physics , meteorology
A bstract : Turbulent wedges induced by a three‐dimensional surface roughness placed on a flat plate were studied using both shear sensitive and temperature sensitive liquid crystals, respectively denoted by SSLC and TSLC. The experiments were carried out at a free‐stream velocity of 28 m/sec at three different favorable pressure gradients. The purpose of this investigation was to examine the spreading angles of the turbulent wedges, as indicated by their associated surface shear stresses and heat transfer characteristics, and to obtain more insight about the behavior of transitional momentum and thermal boundary layers when a streamwise pressure gradient exists. It was shown that under a zero pressure gradient the spreading angles indicated by the two types of liquid crystals are the same, but the difference increases as the level of the favorable pressure gradient increases. The result from the present study is important for modelling the transition of thermal boundary layers over gas turbine blades.