Tuesday, December 25, 2012

Random thoughts (about CFD, etc) on the Christmas Day of 2012

Merry Christmas!

It has been quite an eventful year with my recent job change from Iowa State University (ISU) to the University of Kansas (KU). Many of my colleagues and friends were very surprised (or even shocked) that I would even consider moving to the "dark side" (by being the chairperson of an academic department). I fully agree that something like this would have been unfathomable only two years ago. I have always enjoyed research and teaching as a college professor, and would have been extremely happy doing both for the rest of my life. The person who was the most responsible for this change was Dr. Rich Wlezien, my previous boss and the Vance and Arlene Coffman Endowed Department Chair in Aerospace Engineering at ISU. Rich tapped me to be his Associate Chair for Research and the Director of Graduate Education (or DOGE at ISU) around late 2010. Since I did not volunteer for the position, I agreed to give it a try to see whether the job would distract me from my regular research and teaching. Serving in this role revealed to me a bigger picture of the Department than what I would normally see. With the Graduate Studies Committee, we were able to reform the graduate program in several areas. Earlier, these reforms had been considered beneficial to the entire Department, but not pushed through due to resistance from multiple directions. With extensive discussions and consensus building, the reformed graduate policies received nearly unanimous faculty support. Events like this showed me that a positive impact can be made to an academic environment not only through teaching and research, but also through service, including being a Department administrator. Another person who was also responsible for the change was Dr. Charlie Zheng, my fellow CFDer and colleague at KU, who convinced me to take a look at the opportunity. A heartfelt thank you to both Rich and Charlie.

I have found that both ISU and KU are great places to work. Both aerospace programs are nationally ranked, and have produced very prominent national leaders such as Thornton "T" A. Wilson (ISU alum and former CEO and Chairman of the Board of Boeing), Vance Coffman (ISU alum and former CEO and Chairman of the Board of Lockheed Martin), and Alan Mulally (KU alum and current CEO of Ford). ISU has been known for its CFD program since the 1980s, and its faculty (Tannehill, Pleacher and Anderson) authored one of the most popular CFD text books. ISU has a much larger faculty, has graduated much more students, and ranks higher than KU. KU is known internationally for its aircraft and engine design education. Over the years, KU students have won many AIAA student aircraft and engine design competitions, ranking KU near the top (if not at the top) of all international aerospace programs. KUAE is poised to grow rapidly in the next few years due to the University's strategic plan to grow the engineering faculty by 30% and the number of students by 50%. I hope to strengthen KUAE's research profile so that it will one day rank as high as ISU. Although we loved living in Ames, Lawrence does have the better climate, downtown and variety of restaurants!

I heard a rumor that I changed job because CFD is dead, or my research has hit a big obstacle. I can forcefully state that neither is true. In fact, I intend to continue my CFD research and education in the foreseeable future. I brought nearly my entire group from ISU to KU, and we are working very hard on tackling some of the challenges in high-order adaptive CFD methods (see my previous blog for sample topics). Now and then, we look for talented and hard-working students or postdocs to join our team. If you are motivated and enjoy math, programming and fluid dynamics, you are welcome to apply to KUAE. On CFD education, we are considering to establish a graduate CFD certificate at KUAE, hopefully in the Fall 2013. Do visit KUAE (http://www.ae.engr.ku.edu/) often for updates.

After more than three decades of development, CFD has undoubtedly established itself as a critical tool in the design process of many industries. I am not sure of the market size of commercial CFD software products, but won't be surprised if it is in the order of billions of dollars/year. Constant improvements have been made to these products, which are increasingly more efficient, accurate, robust, and easier to use. There are also many web sites and blogs dedicated to CFD. The fact that these sites and blogs are being visited is a good sign that CFD is well and receiving a lot of attention. I particularly like "Another Fine Mesh", maintained by John Chawner of Pointwise. I just wonder how John manages to run his company and still find time to do the blogs on a weekly basis. 

Almost all CFD commercial software has benefited from research carried out in the "golden age" of CFD, generally considered to be the 1980es, by many well-known CFDers. If we do a survey about the top CFD giants in the world, who have made the most far-reaching impact, I am very confident that the names of Antony Jameson, Phil Roe and Bram van Leer would stand out. In order to celebrate their seminal contrbutions in CFD, an international symposium in their honor is being organized, with support from AFOSR. More information will be posted in the near future with a link from this blog.

BTW, the 2nd International Workshop on High-Order CFD Methods will be held in Germany. See this web site for more info: http://www.dlr.de/as/desktopdefault.aspx/tabid-8170/13999_read-35550/   

Finally, what happened to the often dreamed "push button" CFD tool, which is supposed to give you accurate CFD solutions by pushing a few buttons? Is such a tool going to appear one day, or is it still desired? Let me know your thoughts.

Last but not least, have a great 2013!

Thursday, June 21, 2012

A Very Successful Workshop

This blog is so overdue, since the Workshop concluded nearly six months ago! But better late than never. So here I am, giving you an much delayed update.

After several years of planning, the 1st International Workshop on High-Order CFD Methods was successfully held in Nashville, Tennessee, on January 7 and 8, 2012, just before the 50th Aerospace Sciences Meeting. Over 70 participants from all over the world across the research spectrum of academia, government labs and private industry attended the Workshop. Many interesting results were presented. The major findings from the Workshop include:

1.     For problems with smooth solutions and geometries, high-order methods are able to demonstrate high-order accuracy with h and p-refinement. High-order methods demonstrated better performance than the 2nd-order finite volume method for both steady and unsteady problems based on error vs. cost.

2.     For problems with non-smooth solutions or geometries, high-order methods cannot achieve high-order accuracy as expected. They are comparable to low order methods in performance.

3.     Solution based hp-adaptations have been shown to be very effective in minimizing the computational cost to achieve a given level of accuracy.

4.     For RANS simulations, high-order methods are still not as robust as low order methods in converging to the steady state solution. It is believed that this behavior is related to non-smoothness introduced in the turbulence models.

If you are interested in doing research on high order methods, the following pacing items may interest you:

1.     High-order mesh generation

2.     Solution based hp-adaptations

3.  Scalable, low memory efficient time integrators for RANS and hybrid RANS/LES approaches

4.     Robust, accuracy-preserving and parameter-free shock capturing

Some of the abstracts of the workshop are contained here:

The next workshop will be held in Cologne, Germany next summer. Check the workshop 
web site for updated information.

On a personal note, I will join University of Kansas as the Spahr Professor and Chair of Aerospace Engineering in August 2012. It was a difficult decision, but I do look forward to the new challenges ahead.