Vortex intensity

Figure 1.12 Comparison of calculated axial and radial vortex intensities with experimental data.

The choice of the boundary condition essentially determines the model of force interaction between the particle at the center of the cell and the other particles. A detailed comparative analysis of various boundary conditions was carried out in [450], where the solutions were obtained for the three above-mentioned versions under the assumption that the particle at the cell center was a drop of a liquid with different viscosity. A new variant of closed model was presented also in [450], where it was proposed to believe that the vortex intensity flux is equal to zero on the cell boundary. 

High-Intensity Mixer. Mixers such as that shown in Fig. 18-44 combine a high shear zone with a fluidized vortex mixing action. Blades at the bottom of the vessel scoop the batch upward at peripheral speeds of about 40 m/s (130 ft/s). The high shear stress (to 20,000 s" ) and blade impact easily reduce agglomerates and aid intimate dispersion. Since the energy input is high [200 kW/m (about 8 hp/fE)h even powdery material is heated rapidly. 

For turbine mixers that the width of a baffle should not exceed more than one-twelfth of the tank diameter and, for propeller mixers, no more than one-eighteenth the tank diameter. With side-entering, inclined or off-center propellers, as shown in Figure 13, baffles are not required. Instead, shrouded impellers and diffuser rings may be used to suppress vortex formation. These devices contribute to flow resistance and reduce circulation by creating intense shear and abnormal turbulence... 

The vibration induced by the fluid flowing over the tube bundle is caused principally by vortex shedding and turbulent buffeting. As fluid flows over a tube vortices are shed from the down-stream side which cause disturbances in the flow pattern and pressure distribution round the tube. Turbulent buffeting of tubes occurs at high flow-rates due to the intense turbulence at high Reynolds numbers. 

Eddies are turbulent instabilities within a flow region (Fig. 2). These vortices might already be present in a turbulent stream or can be generated downstream by an object presenting an obstacle to the flow. The latter turbulence is known as Karman vortex streets. Eddies can contribute a considerable increase of mass transfer in the dissolution process under turbulent conditions and may occur in the GI tract as a result of short bursts of intense propagated motor activity and flow gushes. ... 

The characteristic time-scales mentioned above take into account some but not all practical considerations. For example, really intense stirring (rpm > 500) in the CSTR is not recommended for in situ studies since a deep vortex ivill be formed in the liquid, gas ivill be entrained, and tivo-phase flow w ill occur in the recycle line. Also, two-phase flow will generally cause cavitation in a mechanical pump (possibly stopping flow) and induce irreproducible spectroscopic measurements. 

When the Arctic polar vortex is not denitrified, more gas-phase HNO, is available as the sunlight intensity increases, and this photolyzes, regenerating N02 ... 

A certain minimum flow rate is necessary to set up the vortex motion and to establish centrifugal separation forces that grow in intensity as the flow rate increases and improve the separation efficiency. A point will be reached for a given set of conditions, however, beyond which further increases in flow rate will cause performance deterioration. This is caused principally by the following. 

Starting from the flame front the intensity of the vortices remains constant along each streamline, so that the region filled by combustion products is a rotational one. In some of the previous works mentioned, however, the existence of the stagnation zone behind the flame front has not been accounted for, so that the quantitative conclusions diflier essentially from those of the hydrodynamic model presently under consideration. It should be noted that the boundary streamline of the stagnation zone is a tangential velocity component discontinuity surface or a vortex sheet. As a consequence of the... 

Figure 1. 205T1-NMR spectrum (solid line) at 5 K. The intensity is plotted in a linear scale. The thin solid line depict the histogram at particular local fields of the Readfield pattern. The dotted line represents the simulation spectrum convoluted with Lorentzian broadening function. The filled circles show the frequency dependence of 205 f,1 1 at the T1 site. The inset shows the image of the field distribution in the vortex square lattice center of vortex core (A), saddle point (B) and center of vortex lattice (C).

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