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Supermassive black holes are typically surrounded by a dense stellar population in galactic nuclei.Once a star approaches close enough the black hole(BH),it is tidally ripped apart and about half of the stellar debris becomes bound.The bound stellar debris falls back and forms an accretion disk of size about two times the pericenter radius of the star.For a BH of mass 107 M⊙ with M⊙ the solar mass disrupting a solar-type star,the size of disk is less than about 10 times the Schwarzschild radius of the black hole,or about 4 times the radius of red giant star.If a red giant star in the dense nuclear star cluster crosses the line of sight toward the accretion disk by chance,it would cover more than about 6%the disk surface area and cause a significant dip in the flux of the tidal disruption event(TDE).Combining the theoretical modeling of the transit light curve and spectrum at transit,we can observationally investigate the general effect at strong gravity,constrain BH event horizon and spin,and the inclination and structure of the accretion disk.In this poster,we numerically and analytically investigate the transit event rate and the distribution of the duration of eclipse.Our preliminary results show that for a face-on circular accretion disk the transit event rate caused by red giants within the influence radius of the black hole of mass 107 M⊙ is about 0.012 yr-1 and the distribution of the eclipse time is peaked at about 2 days,which is mostly contributed by red giants of orbital periods about 5 years.Here we assumed that the orbits of the red giants are circular and the fraction of the red giants in mass is about 1%of the stellar populations.However,if we assume that the orbits of red giants are elliptical with a thermal equilibrium distribution of eccentricity,the transit event rate would increase about twice to once every 33 years and the peaked eclipse time would decrease a bit.We also investigate the transit even rate and the eclipse time distribution by red giants in the bulge until the gravitational microlensing effect becomes dominated.