ABSTRACT
A traffic transportation tunnel is a highly enclosed man-made domain. In the domain not only the transfers but also the transformations of constituents, momentum, and energy can happen. In that context, the air flow is primarily for maintaining this complex and changeable environment at an acceptable condition for human beings to pass through, or to be free from any hazards. To achieve this purpose, some ventilation systems have been developed. In this chapter, the ventilation systems, flow driving units, flow models, examples, methods of analysis, and major challenges have been introduced.
