Passive chaotic mixing

Passive Chaotic Mixing by Posing Grooves to Viscous Flows Most Relevant Citations... 

This passive chaotic mixing concept is achieved with only minor modification of the flow channel, i.e. placement of only small obstacles, so that a low pressure loss for a given mixing task is expected [58],... 

On the other hand, passive chaotic micromixers typically use complex three-dimensional twisted conduits fabricated in various substrates such as silicon [13], polydimethylsiloxane (PDMS) [14], ceramic tape [15], or glass [13] to create 3-D steady flow velocity with a certain complexity to achieve chaotic advection. T q)ical examples of the aforementioned two routes to achieve chaotic advection and mixing in LOC devices are presented in the following. 

Here we consider aggregation in a physically realizable chaotic flow, the journal bearing flow or the vortex mixing flow described earlier. The computations mimic fast coagulation particles seeded in the flow are convected passively and aggregate upon contact. In this example the clusters retain a spherical structure and the capture radius is independent of the cluster size. 

Another class of good candidates for a study of chaos in nonlinear optics are wave-mixing processes in which chaos appears in the propagation of laser light through passive nonlinear media [93]. A chaotic behavior was observed in three-wave mixing [94] and in four-wave mixing [95]. 

Passive mixing by chaotic advection is demonstrated in a PDMS chip consisting of a winding channel (see Figure 3.43). An essential component is a water-... 

Figure 8.1 Exponential decay of the variance of the concentration fluctuations in an oscillatory reaction mixed by a chaotic flow. The smooth curve shows the decay of the passive scalar variance in the same flow, for comparison (from Kiss et al. (2004)).

Passive micromixers rely on the mass transport phenomena provided by molecular diffusion and chaotic advection. These devices are designed with a channel geometry that increases the surface area between the different fluids and decreases the diffusion path. By contrast, the enhancement of chaotic advection can be realized by modifying the design to allow the manipulation of the laminar flow inside the channels. The modified flow pattern is characterized by a shorter diffusion path that improves the mixing velocity. In this section, an overview of the different types of passive micromixers is provided. Mixed phase passive micromixers can be categorized as ... 

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