The boundary-constraint method for constructing vortex-surface fields

Submitted for the DFD16 Meeting of The American Physical Society The boundary-constraint method for constructing vortex-surface fields1 SHIYING XIONG, YUE YANG, Peking Univ — We develop a boundaryconstraint method for constructing the vortex-surface field (VSF) in a threedimensional fluid velocity field. The isosurface of VSF is a vortex surface consisting of vortex lines, which can be used to identify and track the evolution of vortical structures in a Lagrangian sense. The evolution equation with pseudo-time is solved under the boundary constraint of VSF to obtain an approximate solution of VSF. Using the boundary-constraint method, we construct the VSFs in Taylor-Green flow and transitional channel flow. The uniqueness of VSF are demonstrated with different initial conditions, and the consistency of this boundary-constraint method and the previous two-time approach for constructing VSF is discussed. In addition, the convergence error in the calculation of VSF is analyzed. 1This work has been supported in part by the National Natural Science Foundation of China (Grant Nos. 11522215 and 11521091), and the Thousand Young Talents Program of China. Shiying Xiong Peking Univ Date submitted: 26 Jul 2016 Electronic form version 1.4