This study focuses on the unsteady gas-liquid interaction during the liquid-column-balanced launching process in an individual tube-shape weapon.A three-dimensional transient multiphase flow model was developed based on the volume of fluid interface tracking method coupled with a turbulence model, and validated through corresponding visualization experiments.The results show that compared to conventional two-dimensional models, the three-dimensional simulation more accurately captures the evolution of interface deformation, local instabilities, and asymmetric disturbances.The model successfully reproduces the formation, expansion, and breakup of high-temperature, high-pressure gas cavities, significantly enhancing the spatial resolution and descriptive accuracy of complex gas-liquid interactions.The presence of the liquid column reduces the axial expansion rate of the gas jet, lowers the peak outlet velocity and average temperature of the gas, and leads to weaker shock and expansion wave structures in the flow field, demonstrating effective suppression and buffering effects.
based on the separated aerodynamic admittance functions obtained from previous studies (including the u-component of aerodynamic admittance function (u-AAF) and the w-component of aerodynamic admittance function (w-AAF))，the time domain transformations are firstly conducted to obtain the buffeting force time history considering the different contributions of turbulent wind longitudinal and vertical fluctuating components. And then, the buffeting time-domain is performed on a suspension bridge by ANSYS. Finally, the error of buffeting response based on equivalent aerodynamic admittance is compared. The results indicate that the contribution of aerodynamic admittance in the low-frequency region to the vertical buffeting response is greater than that in the high-frequency region. As the angle of attack is zero, the equivalent aerodynamic admittance has a small error (1.94%) in the buffeting response. while within the range of 2 °~8 ° angle of attack, the error reaches 26.39%~61.20%, with the maximum error occurring at 4 ° angle of attack. It can be seen that in previous buffeting analysis, treating the longitudinal and vertical fluctuating components of turbulent wind field as equivalent would overestimate the actual buffeting response. Therefore, the directional differences of turbulent components should be considered in buffeting analysis of long-span bridges.
