Radiometric forces exerted on a membrane with different accommodation coefficients on either side

The radiometric force arises when a body that is nonuniformly heated by radiation is immersed in a low-pressure gas. This phenomenon results from gas-surface interactions, which are characterized by accommodation coefficients. In turn, these coefficients depend on the gas species and surface properties such as roughness and chemical composition. When the accommodation coefficients are not constant over the body's surface, the radiometric phenomenon arises even if the body temperature is uniform. In the present study, we calculate the force exerted on a thin membrane with different accommodation coefficients on its top and bottom surfaces. The temperature of the membrane is assumed to be higher than that of the surrounding gas. The direct simulation Monte Carlo method is used to span a wide range of Knudsen numbers, including the free-molecular, transitional, and viscous flow regimes. We show that perforations in the membrane increase the radiometric force in the viscous regime.