  Bead-rod-spring models are the foundation of the kinetic theory of polymer
solutions. We derive the diffusion equation for the probability density
function of the configuration of a general bead-rod-spring model in
short-correlated Gaussian random flows. Under isotropic conditions, we solve
this equation analytically for the elastic rhombus model introduced by Curtiss,
Bird, and Hassager [Adv. Chem. Phys. 35 (1976), pp. 31-117].
