Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Jin-Han Xie's Research
Channel Turbulence
Based on the structural ensemble dynamics we analyze the k-ω model of channel turbulence. The choice of order parameter k/ω is the key to showing the solution's multiple-layer structure characterized by distinguished dominant balances. This structure is captured by a class of self-symmetry solutions, which stem from the Lie group analysis of the model equations and match the Karman log-law by expansion. As is shown in the figure on the right, k and ω profiles are well expressed based on these self-symmetry solutions. The multiple-layer structure is not only a property of k-ω model but also discovered in DNS data, this suggests a possibility of improving the k-ω model by DNS data via these self-symmetric multiple-layer solutions.
(This work is supervised by Prof. Zhen-Su She, and collaborated with Dr. Xi Chen and Dr. You Wu.)
Ball lightning
As a rare but interesting natural phenomena, Ball lightning remains a mystery with its strange motion and long lifetime. Speculated plasma phenomena its mechanism may inspire magnetic confinement which is the key for controlled nuclear infusion. In this research originated from the two-fluid equations we propose a plasma model whose stable state can be expressed by double curl equations (∇×∇×B + α∇×B+β B = 0) inside a ball geometry. The in-ball solution can be expressed by force-free field and matches with the outside uncharged fluid velocity and pressure, which indicate the potential influence by the wind hence possible strange path. The long lifetime, which is proportional to the streamline length, could be explained by the chaotic solution, as is shown in the figure on the right by the Poincare intersection of streamline.
(This work is supervised by Prof. Wei-Dong Su.)
