Flow structure consistency analysis between vortex particle method and detached eddy simulation method based on modal decomposition

The vortex particle method (VPM) has been widely used for rotor wake simulation due to its lower numerical dissipation and computational cost. However, the data consistency of flow structure between VPM and high-fidelity methods still lacks systematic analysis. In this paper, the flow over the Caradonna-Tung rotor in hover is simulated using both the VPM and high-fidelity detached eddy simulation (DES) methods to compare the consistency of the load distribution and wake evolution. Two modal decomposition methods, proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD), are introduced to decompose the vorticity field into POD and DMD modes and then analyze the consistency of flow structure described by these modes between VPM and DES results. The research on basic features of load distribution and wake evolution indicates that the VPM can obtain results with accuracy similar to DES results and with less computation cost. The analysis of flow structure consistency finds that VPM has good consistency with the high-fidelity DES method on the dominated flow structures whose characteristic frequencies are rotation frequency, blade passing frequency, and their frequency multiplication.