  We study the long-range spatial correlations in the nonequilibrium steady
state of a randomly driven granular fluid with the emphasis on obtaining the
explicit form of the static structure factors. The presence of immobile
particles immersed in such a fluidized bed of fine particles leads to the
confinement of the fluctuation spectrum of the hydrodynamic fields, which
results in effective long-range interactions between the intruders. The
analytical predictions are in agreement with the results of discrete element
method simulations. By changing the shape and orientation of the intruders, we
address how the effective force is affected by small changes in the boundary
conditions.
