Rarefied Gas Flows over In-line Arrangement of Circular Cylinders

A rarefied gas flow through the infinite expanse of an in-line array, of circular cylinders is considered on the basis of kinetic theory. The temperature of the cylinder, which is uniform in each cylinder and is common in one direction of the array, varies from one cylinder after another with a constant increment in the other direction. A pressure gradient is imposed in the gas in the same direction as the cylinder-temperature variation. A steady flow caused by the pressure gradient and that caused by the temperature variation of the array are investigated numerically on the basis of the linearized Bhatnagar-Gross-Krook (BGK) equation and the diffuse reflection boundary condition. The integral equation approach has been employed in the numerical computation. The mass-flow rate as well as the energy-flow rate of the gas through the periodic unit cell is obtained as a function of the Knudsen number.