The study on the wake of a CLT propeller under different advance coefficients

Abstract

In this paper, the impact of advance coefficients on the characteristics of the CLT propeller wake is investigated and the large eddy simulation turbulence model is employed. A wide range of advance coefficients (0.1∼0.9) are calculated by solving the unsteady Navier-Stokes equations. The verification is performed and the results from the calculations are compared with experimental data. Under smaller advance coefficients, the wake is separated into three flow regimes: free stream, slipstream, and vortices between two regions. The boundaries among the flow regimes are indistinct under bigger advance coefficients. The perturbations induced by the rotating blades get smaller as the advance coefficient increases. Then, the vortical structures represented by the Q isosurface show that the endplate tip vortices merge with the secondary tip vortices, and the merged tip vortices will re-merge downstream. The inner trailing sheet vortices remain further than the outer ones under all advance coefficients. Finally, the trajectories (including the radius, the distance between two consecutive vortices, the pitch) of the vortex-system are analyzed in detail and fitted with different functions. It is recommended that proper considerations should be used for the establishment of the reliable wake model due to the various characteristics of the trajectory.