A gap in phase-space, the loss cone (LC), is openedup by a supermassive black hole (MBH) as it disruptsor accretes stars in a galactic centre. If a starenters the LC then, depending on its properties, itsinteraction with the MBH will either generate aluminous electromagnetic flare or give rise togravitational radiation, both of which are expectedto have directly observable consequences.The thesis begins with a brief review of dynamicalmodelling collisionless galaxies. Then the generalscheme is developed to construct high-resolutionN-body models. Next, a suit of optimized model andcode, both having high-resolution at the centre, areused follow the evolution of flyby encounters for abroad range of satellite parameters. The penultimatechapter describes how the findings are used topredict a MBH fuelling rate driven by orbitingsubstructures within the dark matter halo. Finally, Isummarize the findings and provide some future work.