That Elusive Hum

This article highlights about modern power turbines that have the highest operating efficiencies. These turbines turn out the fewest pollutants among major combustion energy converting devices. In addition, they are attractive because of low capital costs required to bring new systems online. As a result, gas turbines have become the dominant technology for new power generating capacity in the United States and worldwide. Experimentalists have developed new diagnostic tools for making pertinent measurements in the unsteady, harsh combustor environment. In addition, computational advances in simulating these unsteady flows are providing a more complete picture of the relationships among the myriad of unsteady flow processes and flame propagation. The accuracy of simplified, physics-based models that can be used for design-level decisions is improving. Combustion dynamics remains a challenging problem, but the large efforts at university, industry, and government labs advance our understanding and bring us closer to dealing with the problem.