Low Reynolds Number Flows with Slip at Walls in Circular Tubes with Abrupt Enlargements and Contractions

Abstract

The results of finite-difference solutions and experiments on low Reynolds number flows in axisymmetric circular tubes with abrupt enlargements and contractions are reported. Stream-lines and vorticity contours by the solutions with slip boundary conditions for rarefied gas are presented as functions of Reynolds numbers, Knudsen numbers, and momentum accommodation coefficients. Liquid flow visualizations using an aluminium dust method are in accordance with the stream-lines of the numerical solutions with non-slip boundary conditions. Measured pressure distributions of slightly rarefied-flows at the inner walls of the tubes are compared with the numerical solutions with slip boundary conditions.