Fabien Anselmet

A generalization of Yaglom's equation which accounts for the large-scale forcing in heated decaying turbulence

In most real or numerically simulated turbulent flows, the energy dissipated at small scales is equal to that injected at very large scales, which are anisotropic. Despite this injection-scale anisotropy, one generally expects the inertial-range scales to be locally isotropic. For moderate Reynolds numbers, the isotropic relations between second-order and third-order moments for temperature (Yagloms equation) or velocity increments (Kolmogorovs equation) are not respected, reflecting a non-negligible correlation between the scales responsible for the injection, the transfer and the dissipation of energy. In order to shed some light on the influence of the large scales on inertial-range properties, a generalization of Yagloms equation is deduced and tested, in heated grid turbulence ( R λ =66). In this case, the main phenomenon responsible for the non-universal inertial-range behaviour is the non-stationarity of the second-order moments, acting as a negative production term.

Analogy between predictions of Kolmogorov and Yaglom

The relation, first written by Kolmogorov, between the third-order moment of the longitudinal velocity increment δu 1 and the second-order moment of δu 1 is presented in a slightly more general form relating the mean value of the product δu 1(δu i)2, where (δu i)2 is the sum of the square of the three velocity increments, to the secondorder moment of δu i. In this form, the relation is similar to that derived by Yaglom for the mean value of the product δu 1(δu θ)2 where (δu θ)2 is the square of the temperature increment. Both equations reduce to a ‘four-thirds’ relation for inertialrange separations and differ only through the appearance of the molecular Prandtl number for very small separations. These results are confirmed by experiments in a turbulent wake, albeit at relatively small values of the turbulence Reynolds number.

Similarity of energy structure functions in decaying homogeneous isotropic turbulence

An equilibrium similarity analysis is applied to the transport equation for

Turbulent energy scale budget equations in a fully developed channel flow

\langle(\delta q)^{2}\rangle

Investigation of characteristic scales in variable density turbulent jets using a second‐order model

(

Velocity turbulence properties in the near‐field region of axisymmetric variable density jets

{\equiv}\,\langle(\delta u)^{2}\rangle + \langle(\delta v)^{2}\rangle + \langle(\delta w)^{2}\rangle

Simultaneous measurements of temperature and velocity fluctuations in a slightly heated jet combining a cold wire and Laser Doppler Anemometry

), the turbulent energy structure function, for decaying homogeneous isotropic turbulence. A possible solution requires that the mean energy

Turbulent flows and intermittency in laboratory experiments

\langle q^{2}\rangle

Joint statistics between temperature and its dissipation rate components in a round jet

decays with a power-law behaviour (

LDA measurements in a turbulent boundary layer over a d-type rough wall

\langle q^{2}\rangle\,{\sim}\,x^{m}