The culmination of the stream-function-vorticity approach was the publication of the 1969 book “Heat and Mass Transfer in Recirculating Flow” [1], for which Prof. Gosman was the editor, and which included the source code for the CFD tool called ANSWER, developed by Runchal and Wolfshtein. This book marked a turning point for CFD, demonstrating for the first time that industrially relevant flow problems could be solved using numerical simulation, and providing a tool with which to do it. The techniques advocated by this publication were subsequently used to provide the first examples of CFD applied to a recirculating flow exhibiting combustion.

Having demonstrated that the stream-function-vorticity approach could be used to simulate low-speed two-dimensional flow problems, Prof. Spalding and his team began to investigate the extension of the methods to three-dimensions. However, they quickly realized that the solution of Navier-Stokes Equations in three dimensions requires the solution of six equations when cast in terms of stream-function and vorticity, but only four equations if cast in terms of the primitive variables of velocity and pressure.

This realization development was followed quickly by two important developments: the 1976 introduction of Patankar and Spalding’s SIMPLE algorithm variants of which were to form the backbone of almost every CFD code that followed; a year later, Launder and Spalding published the standard k-epsilon model, which provided the first practical method of modeling turbulence without invoking an arbitrary length scale. With these essential ingredients in place, Prof. Spalding’s group were now free to start developing problem specific CFD codes that were capable of addressing real engineering problems. Although simple by contemporary standards, these codes could easily be considered an early prototype for all that followed, performing important role in establishing the credibility of the new discipline of Computational Fluid Dynamics and directly inspiring all of the commercial CFD codes that would eventually follow.

Prof. Gosman’s own contribution during this period was a two-dimensional code called TEACH, which he originally developed (together with Dr W.P. Pun) as an educational tool for the post-experience courses in CFD that Spalding’s team were beginning to offer. With TEACH, Prof. Gosman pioneered the use of CFD in the classroom, introducing numerical simulation into the curriculum for undergraduate mechanical engineering students, authoring the first course to make practical use of CFD as a learning tool for fluid mechanics and heat transfer, and publishing the first text book [2]. This showed tremendous foresight; although CFD techniques were beginning to be tentatively examined in some “high technology” sectors of industry, the release of the first general purpose commercial CFD codes was still half a decade away, and practical fluid mechanics was almost entirely dominated by experimental methods.

Although TEACH was originally conceived as a teaching tool, by publishing the source code (as a 1000 line FORTRAN program at the back of a text book), Prof. Gosman may have inadvertently pioneered the open source CFD movement. TEACH was subjected to much modification and extension, and was probably the most widely used CFD code in the pre-commercial world [3, 4].

The original motivation for Spalding had to been to develop simulation methods for problems involving heat-transfer and combustion, which unlike pure fluid mechanics problems involved recirculation zones that were not easily addressed by either existing theoretical methods or experimental investigation. It was now, in the late 1970s, that some of these ambitions started to be realized, with the first practical simulations of combustion in gas turbines and stationary combustors.