Generation Rate of Turbulent Patches in the Laminar Boundary Layer of a Submersible.

摘要

Suspended particulate in the environment of underwater vehicles has been suspected to be responsible for the generation of turbulent patches in the laminar boundary layer of the vehicle. This speculation, which is supported by much indirect evidence, is examined in this report through an attempt at calculating the turbulent patch generation rate. The method presented herein is based on the premise that patches are generated by those particles entering the boundary layer that are sufficiently large to 'trigger' a turbulent event. Since the triggering mechanism is not known, the choice of a critical particle size will involve some empriricism. An important element of the method is the calculation of the number of particles of a given size and specific gravity that enter the laminar boundary layer, through computation of the particle trajectories in the inviscid flow field about the vehicle.