Nonsteady Fluid Mechanics of Vehicles in Tubes

Citation

Rizk, Magdi Hanna (1974) Nonsteady Fluid Mechanics of Vehicles in Tubes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/8PJF-8H92. https://resolver.caltech.edu/CaltechTHESIS:09242010-152813759

Abstract

A theoretical study is performed to investigate the drag experienced by vehicles travelling in tubes, the pressure distribution and flow velocities resulting from the vehicle's motion. The study deals with both the cases of vehicles accelerating from rest in the tube and vehicles entering a tube at finite speed. The effect of having a vent in the tube is also studied. The unsteady compressible equations are used to describe the flow in the tube. Before the boundary layer fills the tube, an inviscid core-boundary layer formulation is used. However, it is found that the simpler one-dimensional formulation is adequate for describing the flow in the tube. The quasi-steady near-field assumption agrees well with the unsteady near-field solution except for the initial period of low velocities. The solution is compared to that in which compressibility is neglected. It is found that the effect of compressibility is not large for short tubes, low blockage ratios and small velocities. However, its importance increases as the values of these parameters increase. Compressibility may not be neglected during the initial period in the case of vehicles entering tubes at finite speeds.

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