Study on hydrodynamic simulation and depth estimation methods during the descent process of a temperature-depth buoy’s probe

This study proposes a novel methodology for depth estimation of a temperature-depth buoy’s probe based on fluid dynamics simulation. A comprehensive dynamic model of the probe’s descent process is established, deriving time-discrete expressions for velocity and depth. Computational Fluid Dynamics (CFD) simulations are employed to characterize hydrodynamic drag properties during descent. Using FLUENT software, parametric studies on drag forces under varying flow conditions are conducted, with grid independence validated at 1.54 million cells. A fitted drag coefficient equation is subsequently developed. The proposed algorithm iteratively computes the descent profile at a resolution of 0.001 seconds, ultimately establishing a second-order expression for depth versus time of the temperature probe.