TY - JOUR A1 - Gopinath, A A1 - Koch, D L T1 - Hydrodynamic interactions between two equal spheres in a highly rarefied gas. Y1 - 1999/09/ N1 - R827115 JF - PHYSICS OF FLUIDS J1 - PHYS FLUIDS VL - 11 IS - 9 SP - 2772 EP - 2787 ER -