Transverse flow component

In catalyst packings transverse flow components arc automatically established as a result of the nonuniform arrangement and the twisted flow around the pellets. Hollow and full cylinders with a length-to-diameter ratio of 1 3 are particularly effective in this respect. Despite the fact that radial heat transport takes place... 

Due to the similarity of the flow profiles, most of these passive, continuous-flow schemes can, in principle, also be adopted for centrifugally driven flows. In addition, the availability of the Coriolis pseudo force/c (4) offers an intrinsic means for the generation transversal flow components, even in straight radial channels exhibiting a constant cross section (Fig. 8). Due to the scaling of forces //c (13), the Coriolis-force induced mixing is... 

In simple shear flow where vorticity and extensional rate are equal in magnitude (cf. Eq. (79), Sect. 4), the molecular coil rotates in the transverse velocity gradient and interacts successively for a limited time with the elongational and the compressional flow component during each turn. Because of the finite relaxation time (xz) of the chain, it is believed that the macromolecule can no more follow these alternative deformations and remains in a steady deformed state above some critical shear rate (y ) given by [193] (Fig. 65) ... 

Let us consider a laminar steady-state fluid flow in a rectilinear tube of constant cross-section. The fluid streamlines in such systems are strictly parallel (we neglect the influence of the tube endpoints on the flow). We shall use the Cartesian coordinates X, Y, Z with Z-axis directed along the flow. Let us take into account the fact that the transverse velocity components of the fluid are zero and the longitudinal component depends only on the transverse coordinates. In this case, the continuity equation (1.1.1) and the first two Navier-Stokes equations in (1.1.2) are satisfied automatically, and it follows from the third equation in (1.1.2) that... 

Experimental studies of the effect of blocking some part (55 %) of the flow section upon the velocity and temperature fields in a fuel subassembly were continued. The measurements of longitudinal and transverse velocity components have been made by the electromagnetic method with using a local-action sensor. The results obtained have been compared with the corresponding data for a model with smooth pins. 

In that case, significant transverse flow develops, and macrovoids may be entrapped as illustrated in Rg. 9.20. From the solution procedure point of view, fully three-dimensional flow modeling and simulations are not much more difficult than the two-dimensional version however, one needs (1) to discretize the solution domain in 3D instead of 2D (which takes much longer CPU time to solve the pressure distributions and advance the flow front in a time marching scheme) and (2) to measure the transverse permeability of the preform which is much more difficult than measuring in-plane permeability components. ... 

Figure 2.15 (a) Scheme of a transverse flow generation, (b] Fraction of flow vector Q components (maximized over 0) as a function of the channel thickness for the local slip b/L = 1000 and slip fraction (j>2 = 0.5 (solid line), 0.2 (dashed) and 0.9 (dash-dot) (reprinted with permission from Ref 14, copyright 2011, lOP Publishing). 

If the boundary layer is laminar, fluid particles move parallel to the dashed line in Fig. 6.1. There is no opportunity to replace energy converted to heat within the boundary layer by energy transport from the free stream. However, when the boundary layer is turbulent, there are transverse velocity components along the dashed line of Fig. 6.1. This enables the energy going into heat to be replenished from the main stream which, in turn, delays flow separation. The pressure drag will, thus, be less for a turbulent boundary layer than for a laminar one. 

Figure 3.3 indicates, schematically, the major components of a transverse flow supersonic DF cw chemical laser. A precombustor is used to thermally dissociate F2 present in excess in an F2/H2 flame substantial dissociation of... 

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