It has been known for over six decades that the dissolution of minute amounts of high molecular weight polymers in wall-bounded turbulent flows results in a dramatic reduction in turbulent skin friction by up to 70%. First principles simulations of turbulent flow of model polymer solutions can predict the drag reduction (DR) phenomenon. However, the essential dynamical interactions between the ...

A novel numerical scheme has been developed to simulate high speed viscous flows in complex geometries using unstructured grids. A characteristic–filter based shock capturing scheme is applied as a corrector step to a non–dissipative predictor scheme. This algorithm is being used to study shock turbulent boundary layer interactions and this paper presents the results of a turbulent flow at Mach...

For the first time, we have directly measured the transport of a vector magnetic field by isotropic turbulence in a high Reynolds number liquid metal flow. In analogy with direct measurements of the turbulent Reynolds stress (turbulent viscosity) that governs momentum transport, we have measured the turbulent electromotive force (emf) by simultaneously measuring three components of velocity and...

We are concerned with large-scale magnetic-field dynamo generation and propagation of magnetic fronts in turbulent electrically conducting fluids. An effective equation for the large-scale magnetic field is developed here that takes into account the finite correlation times of the turbulent flow. This equation involves the memory integrals corresponding to the dynamo source term describing the ...

In this paper, we investigate the characteristics of a partially coherent flat-topped (PCFT) beam through turbulent atmosphere. The analytical expressions for the spectral density and the beam width of the astigmatic PCFT beams with circular symmetry propagating in turbulent atmosphere are derived. It is shown that the spectral density and beam width of these beams in turbulent atmosphere are h...

An open channel flow can change from a supercritical to subcritical flow with a strong dissipative process: a hydraulic jump. Herein some new measurements of free-surface fluctuations next to the jump toe and integral turbulent scales in the roller are presented with a focus on turbulent hydraulic jumps with a marked roller. The results highlighted the fluctuating nature of the impingement peri...

This paper investigates turbulent velocity estimation using the full correlation analysis (FCA) of spaced antenna (SA) data, and its application to the routine FCA observations of the Buckland Park MF (BPMF) radar. The effects of transmitter beamwidths are investigated, confirming the suggestions of previous authors that wide transmit beam widths lead to an overestimation of the turbulent veloc...

Fully developed homogeneous isotropic turbulent fields, computed by direct numerical simulation, are compared to divergence-free random fields having the same energy spectrum and either the same helicity spectrum as that of the turbulent data, or vanishing helicity. We show that the scale-dependent velocity flatness quantifies the spatial variability of the energy spectrum. The flatness exhibit...

We studied experimentally a new phenomenon of turbulent thermal diffusion of particles which can cause formation of the large-scale aerosol layers in the vicinity of the atmospheric temperature inversions. This phenomenon was detected experimentally in oscillating grids turbulence in air flow. Three measurement techniques were used to study turbulent thermal diffusion in strongly inhomogeneous ...

the energy equation for turbulent flow of fiber suspensions was derived in terms of second order correlation tensors. fiber motion of turbulent energy including the correlation between pressure fluctuations and velocity fluctuations was discussed at two points of flow field, at which the correlation tensors were the functions of space coordinates, distance between two points, and time.