In recent years, fluid convection has played an increasingly important role in environmental problems, which has attracted increasing attention. Scaled physical modeling is an important approach to understand the behavior of fluid convection in nature. However, a common source of errors is conflicting similarity criteria. Here, we present using hypergravity to improve the scaling similarity of gravity-dominated fluid convection, e.g., natural convection and multiphase flow. We demonstrate the validity of the approach by investigating water-brine buoyant jet experiments conducted under hypergravity created by a centrifuge. Considering the influence of the Coriolis force, an evaluation and correction method is presented. Results show that the scaling similarity increases with the gravitational acceleration. In particular, the model best represents the prototype under N3g with a spatial scale of 1/N and a timescale of 1/N2 by simultaneously satisfying the Froude and Reynolds criteria. The significance of centrifuge radius and fluid velocity in determining the accuracy of the scaled model is discussed in light of the Coriolis effect and turbulence. This study demonstrates a new direction for the physical modeling of fluid subject to gravity with broad application prospects.