Sunday, August 16, 2015

Happy Birthday to Academician Zhang Hanxin, China's CFD Pioneer

I did not know anything about CFD when I started college. My childhood dream was to be a fighter aircraft pilot. In the countryside where my parents taught schools (Jiangtou, Leiyang, Hunan), I often saw aircraft flying in the sky, and was fascinated by them. My fascination to aircraft grew even stronger because of a dream. When you are a young kid, the teachers' words are like the Bible. I still remember my physical education (PE) teacher telling us not to wear white clothes at night outside because enemy planes might see us from the sky, and even shoot us. That evening, I had the weirdest dream which I still remember to this day. In the dream, my best friend and I were playing and running in the rice field. Out of nowhere, a plane looking like a soucer appeared afar in the sky. Remembering what the teacher said during the day, I immediately gestured my friend to run for our lives, and we did. The soucer also spotted us, and started to chase and shoot at us. Suddenly, I was shot, and actually died in my own dream. The dream, however, continued with my friend running to my home, telling my parents that I was dead. I got to visualize what's happening lying there dead, without any pain...

I had to give up my pilot dream early in my childhood because I cannot handle spins and had a deep scar in my head. When I was admitted to National University of Defense Technology (NUDT, which, by the way, produced the fastest computer in the world right now according to, I chose the Department of Applied Mechanics, which had majors in rockets and missiles. I was put in the major of solid rocket engines. During my junior year, I decided to switch major to aerodynamics. Shortly after that, Academician Zhang Hanxin, who is a member of Chinese Academy of Sciences, visited NUDT, and introduced me to CFD, which I was immediately attracted to. In my final semester, I spent 3 months doing a senior design project at the China Aerodynamic Research and Development Center (CARDC) in Mianyang, Sichuan to study the artificial compressibility method developed by Professor Zhang. My direct project advisor was Mr. He Fangshang, who told me many stories about Academician Zhang. The favorite one was that Prof. Zhang remembered exactly which pages all the equations were on after he studied a book, for only once. The senior design project was a wonderful experience, which completely hooked me to CFD.

After obtaining my BS degree, I decided to pursue a MS degree at NUDT under the direction of Professor Zhang, who was also an adjunct professor of NUDT. I spent about three or four months in CARDC in 1986 to attend Professor Zhang's lectures on total variation diminishing (TVD) schemes before leaving for Glasgow University in Scotland to pursue my PhD degree sponsored by the Sino-British Friendship Scholarship Scheme. My PhD thesis title was "Total Variation Diminishing Schemes for Steady Flow Computations".

I am indebted to Academician Zhang for first introducing me to CFD, teaching me the basics, and inspiring me with his passion and dedication. His physics based approach to developing numerical methods has a long lasting impact on CFD development. Last month, a CFD workshop was organized in Mianyang, Sichuan, to celebrate Prof. Zhang's 80th birthday. It was a wonderful workshop with many excellent talks by top CFD researchers from all over the world.

Happy 80th Birthday and Best Wishes, Academician Zhang!