 Today he is most widely known for his pioneering work in the field of fire safety engineering.He has been called "the father of modern fire science" for his contribution to the understanding of flame propagation and fire dynamics.He also helped design the first supersonic wind tunnel, identified a signature of the transition to turbulence in boundary layer flows (now known as "Emmons spots"), and was the first to observe compressor stall in a gas turbine compressor (still a major item of research today).