Abstract
The forced wavelengths of Gortler vortices are easily given by the leading edge plates with varying the period of a saw-tooth edge, and the variation of the forced wavelengths makes transformation of secondary instability flows. The experiments with concave channel of 1 m radius of the curvature for main airflow velocity of 2.5m/s were performed using the leading edge plates. Variation in secondary instability flows was tested by smoke visualization and hot-wire measurement, and was examined from viewpoints of maximum disturbance amplitude Kmax. It was confirmed that meandering flows whose (Kmax)max varies linearly with the non-dimensional forced wavelength parameter Λ prevail at 100<Λ<200. On the other hand, horseshoe-type vortices with (Kmax)max= {-.7em}\
aisebox{1.1ex}{.} {.1em}\
aisebox{-0.2ex}{.} 0.35 are formed at Λ of 250 or greater.
