One-way Flow of a Rarefied Gas Induced in a Circular Pipe with a Periodic Temperature Distribution

The steady behavior of a rarefied gas in a circular pipe with a saw-like temperature distribution increasing and decreasing periodically in the direction of the pipe axis is investigated numerically by means of the direct simulation Monte Carlo method. It is shown that a steady one-way flow is induced in the pipe without the help of a pressure gradient for a wide range of the Knudsen number when a series of ditches is dug periodically in the part of the pipe wall with decreasing (or increasing) temperature. The features of the flow are clarified in detail. It is also shown that the flow has a pumping effect. In particular, some data that give the estimate of the maximum compression ratio attained by a pipe consisting of a large number of periods are presented. The present study is the continuation of the previous study in the case of a two-dimensional channel [Y. Sone et a/., Phys. Fluids 8, 2227 (1996)]. It is found that although the induced one-way flow is stronger for the two-dimensional channel, the pumping effect is stronger for the circular pipe.