Vortex rings are one of the fundamental flow structures in nature. In this paper, the generation of circulation and vortex rings by a vortex generator with a static converging conic nozzle exit is studied numerically. Conic nozzles can manipulate circulation and other flow invariants by accelerating the flow, increasing the Reynolds number, and by establishing a two-dimensional flow at the exit...

Industrial CT (computerized tomography) uses a series of 2-dimensional images taken at specific intervals around the entire sample. Basically any type of industrial CT system uses three principal components: an X-ray tube, an X-ray detector, and a rotational stage. Everything is enclosed within a radiation shielding steel/lead/steel cabinet that typically ranges between four and 10 feet cubed. ...

Industrial CT (computerized tomography) uses a series of 2-dimensional images taken at specific intervals around the entire sample. Basically any type of industrial CT system uses three principal components: an X-ray tube, an X-ray detector, and a rotational stage. Everything is enclosed within a radiation shielding steel/lead/steel cabinet that typically ranges between four and 10 feet cubed. ...

Because of the complexity of the flow field in a trailing vortex, prediction of tip vortex cavitation inception on a hydrofoil or a propeller still relies heavily on model tests and application of cavitation scaling. Experiments indicate that the major parameters influencing tip vortex cavitation inception are fluid viscosity (Reynolds number) and free stream nuclei (Weber number). A scaling me...

This paper reports on a flexible Ni micro wire with CNTs embedded into its surface. By using micromachining technology, for the first time, we could implant nanoscale materials into micro-scale metal substrate at room temperature. Thanks to the effective direct contact and the strong interactions between CNTs and the substrate, field emission current of 1.11 mA (current density of 22.2 mA/cm(2)...

A universal characteristic of mesoscale turbulence in active suspensions is the emergence of a typical vortex length scale, distinctly different from the scale invariance of turbulent high-Reynolds number flows. Collective length-scale selection has been observed in bacterial fluids, endothelial tissue, and active colloids, yet the physical origins of this phenomenon remain elusive. Here, we sy...

A 1-D and 2-D cylindrical flow stability is investigated in this paper. A typical velocity profile in a shear layer with infection point is studied first. The fluid motion is decomposed to two parts: the rotational part and shear part. Linear stability analysis shows the rotational part (like rigid body) is stable but the shear part is unstable. Of course, the shear layer with inflection point ...

The flux-tube solution in the dual Ginzburg-Landau (DGL) theory in the Bogomol’nyi limit is studied by using the manifestly Weyl invariant form of the DGL Lagrangian. The dual gauge symmetry is extended to [U(1)]m, and accordingly, there appear three different types of the flux-tube. The string tension for each flux-tube is calculated analytically and is found to be the same owing to the Weyl s...

We examine the behavior of the vortex defects on the world-sheet when a solitonic d5 brane is existing in the d-dimensional target space, and it is seen that the vortices of any charge should be dissociated to the free-gas phase when they approach to the brane. The meanings of this fact are addressed through the analysis of the renormalization group equations on the world sheet. e-mail: gouroku...

Two-phase flow regimes are affected by conduit position, alignment, geometry, flow direction, physical characteristics, and flow rate of each phase as well as the heat flux toward the boundaries. Due to the importance of two-phase flow, numerous regimes have been identified. The first step in studying micro-bubble formation inside a venturi tube is to recognize the type of flow regimes. In this...