A new strategy for constructing microgravity culture environment via gas-liquid coupled oscillatory flow field

The mainstream Rotating Cell Culture System (RCCS) simulates microgravity via three-dimensional dynamic rotation, which differs from true space microgravity in physical mechanisms. In this context, the present investigation innovatively proposes a new microgravity simulation strategy based on Einstein's equivalence principle-establish a stable and controllable quasi-free-fall flow field environment by constructing a gas-liquid coupled oscillatory system inside the U-tube. Based on the analysis of the physical modeling of the oscillating flow field in the vertical U-tube and the CFD-VOF gas-liquid coupling simulation experiments with parameters (D = 15 mm, R/D = 1.3) shown that in each oscillation period, 71% of the liquid will lose weight in two vertical sections, and when the liquid at the maximum volume ratio the average weight loss peak value is 0.02 g, achieving spatial low microgravity (10^-2g), and the dynamic characteristics of the pressure and shear stress of the flow field meet the mechanical boundary conditions of cell culture. This approach is expected to establish a new paradigm for ground-based simulation of microgravity effects in space, offering novel technical/theoretical support.