A subterranean coring assembly can include a body having at least one wall that forms a cavity, wherein the cavity has a top end and a bottom end. The subterranean coring assembly can also include a first flow regulating device movably disposed within the cavity toward the top end, where the first flow regulating device is configured to move from a first default position to a first position within the cavity based on first flow characteristics of fluid that flows into the top end of the cavity toward the bottom end of the cavity.