Slip Flow Boundary Conditions Research Articles

On the theory of thermal forces acting on aerosol particles

Disagreement between experimental results and aerosol thermal force theories for regimes from continuum toward free-molecule is explained through application of first-order slip-flow boundary conditions. The influence of the convective flow on the thermal force is explored through a perturbation technique.

High-Speed Rotating Cylinder for Rarefied Gas Dynamics Research

Recent interest in slip-flow phenomenon as applied to high-altitude supersonic flight problems has revived experimental activity aimed at determining slip-flow boundary conditions and evaluating empirical reflection and accommodation coefficients. A unique rotating cylinder apparatus has been designed and constructed for studies involving rarefied gas-surface interactions over a wide range of flow characteristics extending from continuum conditions to the free molecular flow region. In addition to the above studies the equipment can be used to generate a shear flow field essential to the development of instrumentation necessary for the measurement of rarefied gas flow boundary layers and other nonuniform flow conditions. The flow requirements and design considerations which govern the geometry of the system, the choice of vacuum pumping equipment, vacuum instrumentation, and the controlled speed centrifuge drive mechanism are discussed. The remotely controlled floating torsion balance system is described and the mechanical precision of the entire equipment is indicated.