The authors express their gratitude to Professor Keogh for contributing his keen insights and perspectives and illuminating analysis on the Morton effect (ME) and on general thermally induced, near synchronous, rotordynamic instability problems [1]. Keogh and Morton's [2,3] landmark papers on the theoretical analysis of the ME launched an evolution of the understanding of the ME, which was stimulated by actual industrial experience and improved theoretical models. These models were developed to more accurately predict the ME for design and troubleshooting. This is a timely accomplishment since as recognized by Professor Keogh, modern rotordynamic systems continually push the boundaries in complexity, speed, loads, performance, efficiency, and structural lightness, which amplify higher order vibrational effects that disrupt machinery operation.
Professor Keogh insightfully pinpoints the importance of understanding the transient nature of the ME in his rhetorical question “How Synchronous Is the Morton Effect.” The ME...