Affiliations: Research scholar, Department of Aerospace Engineering,
Indian Institute of Technology, Kanpur 208 016, India. E-mail:
[email protected] | Professor, Department of Aerospace Engineering, Indian
Institute of Technology, Kanpur 208 016, India. E-mail: [email protected]
Abstract: In the present experimental investigation, shear sensitive liquid
crystals have been successfully used to study the flow characteristics and
detect separation in two-dimensional Sduct diffusers of different curvatures.
Tapered-fin vortex generators in two different orientations were used to
control flow separation that was observed on one of the curved walls of the
diffuser. The results were verified by conventional oil flow visualization
technique and excellent agreement was observed. In addition to visualization,
detailed measurements that included wall static pressure, skin friction,
diffuser exit total pressure and velocity distributions were taken in a uniform
inlet flow with Reynolds number of 3.49 × 10^5. These results are presented here
in terms of skin friction distribution, distortion and total pressure loss
coefficients. The extent of the separation zone (in terms of intensity of red
distribution) in the diffuser with and without vortex generators (in both
configurations) compared well with the Preston tube measurements. The present
study demonstrates that shear sensitive liquid crystals can be efficiently used
to study the flow physics in complex internal flows. In addition, the results
also indicate that shear sensitive liquid crystals can be effectively used not
only as flow visualization tool but also to gain quantitative information about
the flow field in internal flows.