Angles of Inclination

In her intern blog, Allyce Jackman discusses applying her Mech Eng degree to CFD.

Going from an academic to a professional setting is a daunting yet exciting transition. After studying a broad range of topics in mechanical engineering there’s both excitement and fear at all the possible options to pursue. I wanted to stay in Santa Fe and had heard amazing things about Flow Science, so I decided to put my hat in the ring for a CFD internship. After a long interview with topics ranging from volcanoes to sales I already had an itch for more. To my delight, I had scored an internship.

Allyce Jackman, Flow Science Intern
Ally along with her mentor, John Wendelbo on National Intern Day.

Discovering my role

When I began as a CFD intern at Flow Science I wasn’t entirely sure what my role would entail. However, I was soon given a general multiphysics track with an emphasis in coating applications. Due to the broad nature of the internship I had to decide my own approach to tackling coating simulations which began with reading paper after paper on coating technology, experiments, and general theory. I often found myself in a sort of chaotic dance between researching and simulating on three different computers. I quickly got to the point where I had so many tabs open that the top of my browser resembled a deck of cards. To say that I was knee-deep in coating research would be appropriate, and I still feel that I haven’t even scratched the surface of what there is to learn.

Wrapping my head around coating

Have you ever thought about how photos get that glossy finish? Or how that primer got in every nook and orifice of your car? Or how all those labels on packaged foods were printed? I can tell you that I certainly hadn’t, and when beginning my journey into coating simulations I had no idea how far this topic could reach. After reading a mountain of research papers, which were more academic in nature, I realized I needed to take a step back and get a better idea of what coating looks like in a manufacturing setting. I watched some videos of large-scale coating machines in action and realized that there is so much to consider when identifying parameters that could be implemented for simulation. A typical roll coating machine will have 5 to 6 rollers, all with different purposes, made of different material, and sometimes running at different speeds. There are rollers for application, metering, drying, and winding. The nature of each roller in conjunction with the nature of a given fluid will determine whether your coating will come out even or riddled with defects, and there are endless configurations.

Getting down to business

When setting up a coating simulation using CFD it is important to identify what results you’re after and what scales they exist on. For instance, when using a large machine (about the size of a smart car) to produce a very thin coating (thinner than a sheet of paper!) you must decide whether to approach the macro, to incorporate machine parameters, or the micro, to capture micron-sized coating thickness. Typically, you will be interested in the micro scale, in which case you have to correctly identify which area of your domain to isolate.

For instance, I set up a validation study in an attempt to capture the ribbing defect resulting from a high capillary number in forward roll coating. My domain was a 25 mm2 block at the meniscus of the two rolls. This block contained 20,000,000 cells and was expected to take 16 days for a 1 second simulation. I let it run over a long weekend and when I returned, the picture I saw after a long render of a significant amount of data points was a beautifully ribbed coating thickness. I celebrated in the early morning office silence as I had correctly chosen the area which would show exactly what I was after.

However, this success on the first try was by no means the norm, and due to my initial lack of knowledge of CFD I needed to elicit a good amount of help from the brilliant minds that fuel Flow Science. In doing this I discovered just how genuinely interested everyone is in CFD and its usefulness in solving problems. I quickly learned how exciting it can be to correctly simulate a problem in FLOW-3D and further validate the accuracy of the program. The staff at Flow Science are obviously highly intellectual but, maybe not as obvious, is their humble and inclusive nature. When making my final presentation to showcase what I had done over the course of my internship it was quite obvious that everyone wanted me to succeed which made this daunting task a lot more approachable. It was so interesting looking back on all the material I had created and realizing how my process had improved compared with my early models which were either overly complicated or missing important information. Participating in this internship at Flow Science not only helped my technical knowledge, but gave me a lot of insight into how to work efficiently and organize my work to make for a compelling presentation.

Editor’s note: After completing a very successful internship, Ally will join the Flow Science Sales team as a full-time CFD Engineer in November.