In order to identify coherent structure of turbulent shear flow, a new combination of...

Upper bounds on general dissipation functionals

Cross correlations between normal and downstream velocity fluctuations in a turbulent shear flow are shown to carry information about the non-normal amplification process. The creation of spanwise modulated streaks by downstream vortices implies an asymmetry in temporal correlation functions. We

1.1 Basic definitions and notation Turbulent diffusion can be defined as the study of how a fluid in turbulent motion transports foreign substances that it contains. There are many examples, including smoke, acid rain, and other pollution in the atmosphere, salt in the sea and estuaries, and hot

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Exact coherent structures are three-dimensional, nonlinear traveling wave solutions of the Navier-Stokes equations. These solutions are typi-cally unstable from onset, yet they capture the basic statistical and struc-tural features of low Reynolds number turbulent shear flows remarkably well

Direct numerical simulation of turbulent homogeneous shear ow is performed in order to clarify compressibility effects on the turbulence growth in the flow. The two Mach numbers relevant to homogeneous shear flow are the turbulent Mach number Mt and the gradient Mach number Mg. Twoseries

. The turbulent dynamo action in a shear flow is considered by making use of a quasilinear approximation and neglecting the back-reaction of a generated magnetic field on turbulence. The shear can stretch turbulent magnetic field lines in such a way that turbulent motions may become suitable

Stochastic Structural Stability Theory (SSST) provides an autonomous, deterministic, nonlinear dynamical system for evolving a turbulent mean state. In this work SSST is applied to the problem of understanding the origin and dynamics of roll/streak structures associated with both transition

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