Applied Mathematics Seminar | Gustaaf Jacobs, Lagrangian Coherent Structures and DNS with Discontinuous Galerkin methods

High-fidelity numerical tools based on high-order Discontinuous-Galerkin (DG) methods and Lagrangian Coherent Structure (LCS) theory for the study of separated, vortex-dominated flows are discussed. A numerical framework is presented that couples a higher-order DG-DNS solver with time-dependent analysis of the flow through LCS . At heart of this framework lies an algorithm that computes Finite-Time Lyapunov Exponent (FTLE) fields simultaneously with DNS and with spectral accuracy. The algorithm is applied to investigate the role of LCS in fluid mixing in the unstable bottom boundary layer under a solitary surface wave mimicked by a soliton-like pressure gradient driven flow in an oscillating water tunnel. The development of wwo and three-dimensional LCS fields for the unsteady separated flow over a NACA 65-(1)412 airfoil at a free-stream Reynolds number of Re=20,000 is also discussed.

*This is a joint event with The Water Institute