摘要

Direct numerical simulation (DNS) is used to investigate the development of a turbulent wake created by an impulsively accelerating axisymmetric self-propelled body below a non-deformable free surface. The manoeuvring body is represented by the combination of an immersed boundary method and a body force. The Reynolds number based on either the diameter of the virtual body or the jet forcing intensity is relatively high (O (1000)), corresponding to the fully turbulent case. The vertical growth of the coherent structure behind the body is restricted by the upper and lower stress-free layers, and the wake signatures are observed to penetrate to the free surface. The late-time behaviour of the dipole induced due to vertical confinement can be predicted by scaling laws, also relevant to a stratified fluid.

  • 出版日期2012