The goal of this study is the investigation of the promising secondary flow control technique of non-axisymmetric end wall profiling in a more engine representative environment. In this work end wall profiling is applied to the first stage of a high work, 1.5 stage, unshrouded turbine. Without purge flow non-axisymmetric end wall profiling has demonstrated a considerable increase of total-to-total efficiency. The two designs increased the total-to-total efficiency by 1% and 0.3% respectively relative to a baseline efficiency of already 91%. The first end wall design having the...