The motivation behind this paper comes from the large-scale coherence that has been recently reported in the near-wall and logarithmic regions of wall-bounded turbulent flows. Associated with these are inclined vortical structures that populate the near-wall region. Most often these inclined structures have been inferred as hairpin shaped vortices that have been observed experimentally and evid...

Recent experiments have shown intriguing regions of intense luminescence or ‘hotspots’ in the vicinity of triple-point shear layers in propagating gaseous detonation waves. Localized explosions have also been observed to develop in these fronts. These features were observed in higher effective activation energy mixtures, but not in lower effective activation energy mixtures. The increased lead ...

balance, breakdown of balance, and generation of inertia–gravity waves in vortical flows are fundamental topics of prime importance in geophysical fluid dynamics. this research aims to find the optimum balance relation as well as the rossby-number variation of the spontaneous generation of inertia–gravity waves in a baroclinic, two-layer, boussinesq model on a doubly-periodic f-plane geometry f...

Utilizing an eigenfunction decomposition, we study the growth and spectra of energy in the vortical (geostrophic) and wave (ageostrophic) modes of a three-dimensional (3D) rotating stratified fluid as a function of ǫ = f/N , where f is the Coriolis parameter and N is the Brunt-Vaisala frequency. Throughout we employ a random large scale forcing in a unit aspect ratio domain and set these parame...

An investigation of a model of turbulence generation in the wall region of a turbulent boundary layer is made through direct numerical simulations. The model is based on the instability of a streak. First, a laminar boundary layer disturbed by a continuous blowing through a slot is simulated in order to reproduce and further investigate the results reported from the experiments of Acarlar & Smi...

A collaborative experimental effort employing the minimally perturbed atmospheric surface-layer flowover the salt playa ofwesternUtah has enabled us tomap coherence in turbulent boundary layers at very high Reynolds numbers, Reτ ∼ O(106). It is found that the large-scale coherence noted in the logarithmic region of laboratory-scale boundary layers are also present in the very high Reynolds numb...

We show that gyrotactic motility within a steady vortical flow leads to tightly clustered aggregations of microorganisms. Two dimensionless numbers, characterizing the relative swimming speed and stability against overturning by vorticity, govern the coupling between motility and flow. Exploration of parameter space reveals a striking array of patchiness regimes. Aggregations are found to form ...

In the presence of dense matter quantum anomalies give rise to two new transport phenomena. An anomalous current is generated either by an external magnetic field or through vortices in the fluid carrying the anomalous charge. The associated transport coefficients are the anomalous magnetic and vortical conductivities. Whereas a Kubo formula for the anomalous magnetic conductivity is well known...

Interactions of microswimmers with their fluid environment are exceptionally complex. Macroscopic shear flow alters swimming trajectories in a highly nontrivial way and results in dramatic reduction of viscosity and heterogeneous bacterial distributions. Here we report on experimental and theoretical studies of rapid expulsion of microswimmers, such as motile bacteria, by a vortical flow create...