Weber number aerodynamic

The Weber number. We, is defined as foUows and represents the ratio of the dismptive aerodynamic forces to the restoring surface tension forces. 

Farago and Chigier 2l() found that at similar aerodynamic Weber numbers, the disintegration modes of a thin liquid sheet in air streams are similar to those of a round liquid jet in a coaxial air stream (Table 3.2). At high aerodynamic Weber numbers, Membrane-Type or Fiber-Type breakup mode may set in. 

Isolated Droplet Breakup—in a Velocity Field Much effort has focused on defining the conditions under which an isolated drop will break in a velocity field. The criterion for the largest stable drop size is the ratio of aerodynamic forces to surface-tension forces defined by the Weber number, N (dimensionless). 

The effect of the Weber number on the breakup time (and length) is shown in Fig. 3.12 for several values of initial disturbance amplitude and two values of the density ratio e. It can be seen that breakup time decreases as the Weber number is increased. This is because the bigger the Weber number, the larger the aerodynamic interactions between the liquid sheet and the surrounding gas, and the latter is what enables the growth of the surface waves and the eventual disintegration of the sheet. In addition, the breakup time is reduced by a larger value of the initial disturbance... 

The two most important forces governing the breakup of drops are the disruptive aerodynamic force and the restorative surface tension force. Their ratio results in the nondimensional Weber number ... 

The aerodynamic deformation effect on a moving droplet can be defined by the Weber number (see Chapter 6) ... 

The relation obtained in (32.20) shows that the effective surface tension for a droplet is dependent on how close the droplet charge is to the Rayleigh limit charge. If the Weber number (32.17) is rearranged and the critical Weber number, at which aerodynamic forces become important, is treated as a constant we get the following ... 

The Weber number forms the ratio of the dismpting aerodynamic force to the restorative surface tension force and the Ohnesorge number represents the ratio of... 

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