Eddy formation

Figure 6. Shows turbulent eddy formation in the lee of a cliff.

Figure 8.5 shows a Venturi meter. The theory is the same as for the orifice meter but a much higher proportion of the pressure drop is recoverable than is the case with orifice meters. The gradual approach to and the gradual exit from the orifice substantially eliminates boundary layer separation. Thus, form drag and eddy formation are reduced to a minimum. 

Figure 5.4. Eddy formation at the edge of a jet issuing into a tank illustrates the importance of velocity gradients in eddy diffusion coefficient.

Recycle-flow Mixing Based on Eddy Formation... 

In the zone of the MRC, the proportions of the contributions of the mean motion and of the synoptic and inertial variabilities to the total kinetic energy were 50 40 10, which is close to the estimates based on the data of moored buoy observations (see above). Thus, in the Black Sea, the relative contribution of the kinetic energy of synoptic fluctuations is sixfold lower than in the World Ocean. In the opinion of the authors of [25], this may be related to the small sizes of the sea and to the correspondingly high ratio R /L, where llL is the baroclinic Rossby radius and L is the half-width of the basin. In the Black Sea, R /L = 0.1, while in the World Ocean R /L = 0.01. At R /L > 1, no baroclinic mechanism for eddy formation cross section be implemented. 

An early study by Bixler and Rappe [88] showed that glass beads (up to 100 p,m size) added to a stirred cell UF of a macrosolute were able to significantly enhance flux. The mechanism was probably eddy formation and thinning of the concentration boundary layer by particle interaction. Similar effects were reported by Fane [89] who noted that enhancement required significantly supramicron particles and that smaller particles could in fact add to the deposit resistance. 

The narrow zones of current shear manifested themselves on the SAR images (Figures la and 4-6) as narrow bright (light) lines. Their shape and position reflected the surface current patterns, associated with the eddy formations which perturbed the oil band. The quantitative estimates of surface currents (0.4-1.2 ms"1) and current shear (roughly (0.7-0.8)10 3 s"1)... 

Eddy formation Figure 11.4. Boundary layer separation... 

The movement of a chemical substance within the vapor phase occurs by the combined driving forces of flow and diffusion. An illustration of these effects can be visualized by considering a smokestack plume in the absence of wind, the plume will rise vertically in a more or less uniform column until it reaches an elevation where density considerations result in its spreading out into a relatively broad and flat mantle. When wind is factored into the equation, the plume may move in a more nearly horizontal direction, more or less parallel to the surface of the ground, and at certain wind speeds the plume structure can break up into loops or bends due to turbulent aerodynamic effects such as eddy formation. In addition, small eddies can result in the breakdown of the coherent plume structure, with the formation of... 

Figure 3. Possible conditions of the momentum boundary layer around a submerged solid sphere with increasing relative velocity. Key a, envelope of pseudo-stagnant fluid b, streamline flow c, flow separation and vortex formation d, vortex shedding e, localized turbulent eddy formation. Reproduced, with permission, from Ref. 38. Copyright 1981, Springer-Verlag.

Convective mixing in the direction of flow due to eddy formation or turbulence. 

Vibration due to axial or parallel flow results from the development of eddies along the tube. Axial or parallel flow eddy formation occurs when there are long, unsupported tube spans, relatively narrow shellside flow passages, and very high axial flows. Vibration due to this phenomenon rarely occurs in industrial heat exchangers. 

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