Radial velocity component

Cy is the absolute radial velocity component at the entrance is the absolute radial velocity component at the exit... 

If the fluid enters the pipe from a duct of larger cross-section, the existence of a radial velocity component gives rise to the formation of a vena contractu near the entry to the pipe but this has been neglected here. 

The radial velocity component Vr is negligible compared with the axial component Fz. 

Global velocity distribution behind flame front. Upward propagation in 5.15% methane/air mixture, (a) vector map, (b) and (c) scalar maps of axial and radial velocity components, respectively. Spots are caused by condensation of water vapor on the glass walls. 

Fig. 11. Full-bed and WS mesh comparisons of axial and radial velocity components (at Z3).

Dispersion in packed tubes with wall effects was part of the CFD study by Magnico (2003), for N — 5.96 and N — 7.8, so the author was able to focus on mass transfer mechanisms near the tube wall. After establishing a steady-state flow, a Lagrangian approach was used in which particles were followed along the trajectories, with molecular diffusion suppressed, to single out the connection between flow and radial mass transport. The results showed the ratio of longitudinal to transverse dispersion coefficients to be smaller than in the literature, which may have been connected to the wall effects. The flow structure near the wall was probed by the tracer technique, and it was observed that there was a boundary layer near the wall of width about Jp/4 (at Ret — 7) in which there was no radial velocity component, so that mass transfer across the layer... 

Most studies of hydrocyclone performance for particle classification have been carried out at particle concentrations of about 1 per cent by volume. The simplest theory for the classification of particles is based on the concept that particles will tend to orbit at the radius at which the centrifugal force is exactly balanced by the fluid friction force on the particles. Thus, the orbits will be of increasing radius as the particle size increases. Unfortunately, there is scant information on how the radial velocity component varies with location. In general, a particle will be conveyed in the secondary vortex to the overflow, if its orbital radius is less than the radius of that vortex. Alternatively, if the orbital radius would have been greater than the diameter of the shell at a particular height, the particle will be deposited on the walls and will be drawn downwards to the bottom outlet. 

Mixing is by diffusion only, that is, there are no radial velocity components. 

Two or more of these conditions can occur at the same time, resulting in asymmetric axial, radial and tangential velocity vectors. Some flowmeters are more sensitive than others to particular types of flow distortion, e.g. orifice meters are affected by pure swirl more than venturi meters are magnetic flowmeters are unaffected by changes in the radial velocity component whereas ultrasonic time-of-flight meters are highly susceptible thereto swirl and asymmetry have the least effect on positive displacement meters and the greatest effect on variable area meters. 

F steady dimensionless function corresponding to the radial velocity component... 

Mr Gas radial velocity component Vs Static angle of internal friction... 

Example 2.2 The Radial Velocity in a Steady, Fully Developed Flow Show that in a steady, fully developed flow of an incompressible liquid in a pipe, the radial velocity component vanishes. 

Whipple s careful experimental study of the velocity profile in the region before and after the capillary exit is an initial step in answering some of these needs. He found that polymer melts anticipate the swelling phenomenon, in that, just before the exit, axial decelerations and radial velocity components are observed. Thus the exit velocity profile is not the same as in the fully developed region and the flow there is not viscometric.4... 

The radial velocity component of the fluid, tv, can be computed from the equation (13)... 

The velocity and temperature profiles are assumed to be symmetrical about the center line of the pipe and the radial velocity component, v, is therefore zero on the center line. The boundary conditions on the solution on the center line are therefore ... 

Because the velocity profile is fully developed, the radial velocity component, i.e., v, is zero. The energy equation for the situation here being considered is therefore as given in the previous section, i.e. ... 

State with no entrance effects or radial velocity components body forces are neglected axial heat conduction is small compared to radial conduction Region I of Smith-Ewart kinetics (i.e., when micelles are first forming) is neglected and the initiator concentration is constant. The model may be summarized as ... 

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