EPR made up of immobile elements

In this chapter, several simple flow models will be considered for different structures of the easily penetrable roughness. Generally, two EPR structures will be investigated. In Section 3.1, it will be taken for simplicity that the EPR consists of small spheres trapped in the volume. Therefore, no equations will be required for characterizing the medium of obstruction . This structure is called the EPR made up of immobile elements . In contrast, the obsUuctions in Section 3.2 will be allowed to move along the wind ( EPR made up of mobile elements , or Droplet EPR ). Analytical solutions will be derived whenever it is possible. 

Various flows of gases or liquids in pipelines or in ducts are often met in engineering sciences. Besides the practical importance, such flows represent the simplest possible geometry in fluid mechanics and thus gave base for a number of fundamental investigations of laminar and turbulent flows and their complications with heat and mass processes [380, 566], 

The generalization of such problems by introducing easily peneuable layers within the tube or duct, i.e. layers with disUibuted force (1.7), is oriented to a number of applications and brings also a light to main mechanisms associated with such flows. The applications include the water purification by porous inserts into pipelines, flows in vibrators, in journals and bearings with fibrous insets or brushes, in heat exchangers, 

Gayev and J.C.R. Hunt(eds.), Flow and Transport Processes with Complex Obstructions, 89-178. 2007 Springer. 

This penetrable roughness structure resembles a model of forest . The purpose of this section is the consideration of such simple structure in a flow taken in several common arrangements of fluid mechanics. 

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