To show the effects of the particles and forced disturbances on the instantaneous large-scale vortex structures in a gas-particle round jet, coherent structures in gas-particle turbulent round jets were investigated experimentally by flow visualization. The 45m and 350m diameter glass beads were used as the particles in the experiments. An acoustic speaker was used to introduce velocity perturb...

Recent developments in dynamical systems theory have revealed long-lived and coherent Lagrangian (i.e., material) eddies in incompressible, satellite-derived surface ocean velocity fields. Paradoxically, observed drifting buoys and floating matter tend to create dissipative-looking patterns near oceanic eddies, which appear to be inconsistent with the conservative fluid particle patterns create...

This work reports evidence for the existence of coherent structures in steady-state shear-flow driven plasmas in the Large Plasma Device W. Gekelman et al., Rev. Sci. Instrum. 62, 2875 1991 facility at UCLA. The measurements are performed with the vorticity probe VP , a probe that directly measures the plasma vorticity associated with the E B shear flow by means of a method that is both simpler...

this paper proposes a novel approach for coherent generators online clustering in a large power system following a wide area disturbance. an interconnected power system may become unstable due to severe contingency when it is operated close to the stability boundaries. hence, the bulk power system controlled islanding is the last resort to prevent catastrophic cascading outages and wide area bl...

A reduced description of exact coherent structures in the transition regime of plane parallel shear flows is developed, based on the Reynolds number scaling of streamwise-averaged (mean) and streamwise-varying (fluctuation) velocities observed in numerical simulations. The resulting system is characterized by an effective unit Reynolds number mean equation coupled to linear equations for the fl...

Zonal flows are azimuthally symmetric plasma potential perturbations spontaneously generated from small-scale drift-wave fluctuations via the action of Reynolds stresses. We show that, after initial linear growth, zonal flows can undergo further nonlinear evolution leading to the formation of long-lived coherent structures which consist of self-bound wave packets supporting stationary shear lay...

Effective composition in visual arts relies on the principle of movement, where the viewer’s eye is directed along subjective curves to a center of interest. We call these curves subjective because they may span the edges and/or center-lines of multiple objects, as well as contain missing portions which are automatically filled by our visual system. By carefully coordinating the shape of object...

The expressive visualization of (time-dependent) 3D blood flow along with the vessel wall is essential for understanding vascular diseases. However, the high complexity of the underlying flow data makes the exploration challenging. For the biomedical research, it is necessary to provide methods that allow for rapid flow comprehension, ideally by emphasizing relevant flow characteristics. Theref...

Transport and mixing processes in fluid flows are crucially influenced by coherent structures and the characterization of these Lagrangian objects is a topic of intense current research. While established mathematical approaches such as variational methods or transfer-operatorbased schemes require full knowledge of the flow field or at least high-resolution trajectory data, this information may...

Finite time coherent sets [Froyland et al., 2010] have recently been defined by a measure-based objective function describing the degree that sets hold together, along with a Frobenius–Perron transfer operator method to produce optimally coherent sets. Here, we present an extension to generalize the concept to hierarchically define relatively coherent sets based on adjusting the finite time coh...