Microactuator Arrays for Sublayer Control in Turbulent Boundary Layers Using the Electrokinetic Principle

Micro Electro Kinetic Actuator (MEKA) Arrays for Active Sublayer Control of Turbulent Boundary Layers

Transitional-turbulent spots and turbulent-turbulent spots in boundary layers.

Two observations drawn from a thoroughly validated direct numerical simulation of the canonical spatially developing, zero-pressure gradient, smooth, flat-plate boundary layer are presented here. The first is that, for bypass transition in the narrow sense defined herein, we found that the transitional-turbulent spot inception mechanism is analogous to the secondary instability of boundary-laye...

A deterministic model for the sublayer streaks in turbulent boundary layers for application to flow control.

We present a relatively simple, deterministic, theoretical model for the sublayer streaks in a turbulent boundary layer based on an analogy with Klebanoff modes. Our approach is to generate the streamwise vortices found in the buffer layer by means of a vorticity source in the form of a fictitious body force. It is found that the strongest streaks correspond to a spanwise wavelength that lies w...

Characteristic length scale of the intermediate structure in zero-pressure-gradient boundary layer flow.

In a turbulent boundary layer over a smooth flat plate with zero pressure gradient, the intermediate structure between the viscous sublayer and the free stream consists of two layers: one adjacent to the viscous sublayer and one adjacent to the free stream. When the level of turbulence in the free stream is low, the boundary between the two layers is sharp, and both have a self-similar structur...

Mechanics of inhomogeneous turbulence and interfacial layers

The mechanics of inhomogeneous turbulence in and adjacent to interfacial layers bounding turbulent and non-turbulent regions are analysed. Different mechanisms are identified according to the straining by the turbulent eddies in relation to the strength of the mean shear adjacent to, or across, the interfacial layer. How the turbulence is initiated and the topology of the region of turbulence a...