This paper investigates the influence of boundary layer skew on flow structure, total pressure loss, and flow control technique numerically on a high-loaded axial-flow compressor cascade. We have developed two new models respectively about loss evaluation and end wall flow control mechanism for more specific analysis. The result shows that boundary layer skew weakens the secondary flow and delays the generation of passage vortex when incidence approaches 0°. This results in a reduction of total pressure loss mainly (89.4%) due to relieved corner separation. However, as incidence exceeds a certain value (+7°), severe corner separation or even earlier corner stall can be induced by inlet boundary layer skew. Optimization procedure for profiled end wall at inflow condition of +7° incidence is further carried out to investigate the impact of boundary layer skew on flow control technique. The result shows that boundary layer skew should be counted in the optimization design of profiled end wall because of its significant influence on the development of end wall flow. The optimum profiled end walls for cases with and without boundary layer skew show great difference in the manner of end wall flow control. According to the improvement of cascades’ performance, end wall profiling seems more efficient in reducing loss when influenced by the boundary layer skew.

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The exchanged hypercube EH(s, t), proposed by Loh et al. [The exchanged hypercube, IEEE Transactions on Parallel and Distributed Systems 16 (9) (2005) 866-874], is obtained by removing edges from a hypercube Q s+t+1 . This paper considers a kind of generalized measures κ (h) and λ (h) of fault tolerance in EH(s, t) with 1 s t and determines κ (h) (EH(s, t)) = λ (h) (EH(s, t)) = 2 h (s + 1 − h) for any h with 0 h s. The results show that at least 2 h (s + 1 − h) vertices (resp. 2 h (s + 1 − h) edges) of EH(s, t) have to be removed to get a disconnected graph that contains no vertices of degree less than h, and generalizes some known results.