2 9 Ju l 2 00 3 Fluctuations of energy injection rate in a shear flow Jörg
نویسنده
چکیده
We study the instantaneous and local energy injection in a turbulent shear flow driven by volume forces. The energy injection can be both positive and negative. Extremal events are related to coherent streaks. The probability distribution is asymmetric, deviates slightly from a Gaussian shape and depends on the position in shear direction. The probabilities for positive and negative injection are exponentially related, but the prefactor in the exponent varies across the shear layer.
منابع مشابه
Fluctuations of energy injection rate in a shear flow
We study the instantaneous and local energy injection in a turbulent shear flow driven by volume forces. The energy injection can be both positive and negative. Extremal events are related to coherent streaks. The probability distribution is asymmetric, deviates slightly from a Gaussian shape and depends on the position in shear direction. The probabilities for positive and negative injection a...
متن کاملar X iv : p hy si cs / 0 30 71 10 v 1 2 3 Ju l 2 00 3 Probability density function of turbulent velocity fluctuations in rough - wall boundary layer ∗
The probability density function of single-point velocity fluctuations in turbulence is studied systematically using Fourier coefficients in the energy-containing range. In ideal turbulence where energy-containing motions are random and independent, the Fourier coefficients tend to Gaussian and independent of each other. Velocity fluctuations accordingly tend to Gaussian. However, if energy-con...
متن کاملar X iv : c on d - m at / 0 40 77 55 v 1 2 9 Ju l 2 00 4 Shearing behavior of polydisperse media
We study the shearing of polydisperse and bidisperse media with a size ratio of 10. Simulations are performed with a the two dimensional shear cell using contact dynamics. With a truncated power law for the polydisperse media we find that they show a stronger dilatancy and greater resistance to shearing than bidisperse mixtures. Motivated by the practical problem of reducing the energy needed t...
متن کاملEnergy dissipation in a shear layer with suction*
The rate of viscous energy dissipation in a shear layer of incompressible Newtonian fluid with injection and suction is studied by means of exact solutions, nonlinear and linearized stability theory, and rigorous upper bounds. The injection and suction rates are maintained constant and equal and this leads to solutions with constant throughput. For strong enough suction, expressed in terms of t...
متن کاملAnalysis of the Characteristics, Physical Concepts and Entropy Generation in a Turbulent Channel Flow Using Vortex Blob Method
In this paper, using vortex blob method (VBM), turbulent flow in a channel is studied and physical concepts of turbulence are obtained and discussed. At first, time-averaged velocities, and , and then their fluctuations are calculated. To clarify turbulence structures, velocity fluctuations and are plotted. It is observed that turbulence structures occupy different positions and move with con...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2003