Professor Clayton T. Crowe of Washington State University (WSU) made seminal contributions in the discipline of Fluids Engineering, starting with his early work on solid fuel combustion for rocket launching applications. In the mid-1970s he developed and applied the now well-known particle-in cell model, where a droplet phase is a source of mass, momentum, and energy for the gaseous phase. He then worked with his WSU colleague Dave Stock in developing computational methods for predicting the performance of electrostatic precipitators and cyclone separators. Spray drying has been an enduring part of his research work and a motivation for developing a number of modeling and numerical procedures to capture the thermal and momentum coupling between the dispersed and carrier phases. Since the mid-1980s, Clayton was devoted to tackling some of the very fundamental issues of two-phase dispersed flows. He contributed to the theory of two-fluid modeling and how one obtained the “continuum” equations for high dispersed phase volume fractions from the various averaging procedures. He wrote very lucidly on this subject and much of this formed the appendices in his Multiphase Flows with Droplets and Particles book. He was also interested in the carrier phase turbulence, in particular turbulence modulation caused by suspended particles and particle segregation. While contributing significantly in research, he was also an excellent teacher. He received several excellence-in-teaching awards and his undergraduate book Engineering Fluid Mechanics (co-authored with several other of his colleagues) has been one of the most popular undergraduate fluid mechanics textbooks for over 35 years. He received the “Fluids Engineering Award” from the ASME and the “Senior Multiphase Flow Award” in the 2001 International Conference on Multiphase Flow (ICMF).
Clayton T. Crowe was an enthusiastic member of the ASME and served admirably on the Fluids Engineering Division and the Journal of Fluids Engineering. He was an Associate Editor of the Journal and under his leadership the Multiphase Flow Technical Committee of the ASME grew significantly; he was elected in the Executive Committee of the Fluids Engineering Division and served as its Chair. Apart from his research and educational accomplishments, Clayton T. Crowe had a remarkably pleasant and unassuming personality. He was amiable, modest, easily approachable, with a good sense of humor and always full of energy. He made a point not to be defined by his excellent scientific work; his standing in the multiphase community; his publications and grants and was a scientist with an engaging personality. With his excellent interpersonal skills, his sense of humor and his impeccable scientific credentials, he was a brilliant ambassador of the multiphase flow community. He approached everyone; he laughed at everything with his contagious laugh; he talked to and encouraged all young researchers in the field. He represented one of the rare combinations of educator/researcher/mentor who has deservedly earned the admiration of his colleagues, his peers, and his students.
The Multiphase Flow Technical Committee of the ASME dedicated the 15th International Symposium on Gas-Particle Flows to the Memory of Professor Clayton T. Crowe. The Symposium took place in Chicago Illinois in August 2014 during the ASME-FED Summer Meeting. Twenty-six excellent papers were presented at the Symposium. This Special Issue of the Journal of Fluids Engineering contains several of the papers that were presented at the meeting.
The guest editors of this Special Issue would like to thank all of the authors for their contributions and all of the reviewers for their assistance in reviewing and improving the quality of all the papers. Finally, we would like to thank the Journal of Fluids Engineering Editor, the Editorial Office, and the ASME Production Team for their encouragement and assistance during the course of this publication.
