空投货台摆荡阶段流体-固体耦合建模分析

为获得空投货台摆荡阶段的精确动力学响应,考虑货台大幅度摆荡对空气产生的非定常效应,基于平衡点法构建了空投吊挂系统多体动力学模型,并采用基于ALE格式的有限体积法建立了空气流场模型,在此基础上推导建立了非定常流动作用下的货台-空气流体-固体耦合分析模型。通过数值算例研究:验证了该多体动力学模型的鲁棒性和正确性;明确了层流非定常模型能较好地描述流体对平板的作用力,可用于空投货台摆荡阶段的流场分析;对比指出通过流体-固体耦合分析得到的非定常流动气动力显示出震荡特性,而定常流动假设模型会给货台带来类似粘滞阻尼的特性,其减速效果要比非定常流动模型强烈。

Fluid-structure Interaction Modelling of Airdrop Cargo Platform Swinging

A platform-sling model is established to study the dynamic response of airdrop platform. An uniform equivalent point Newton-Rapshon iteration method is presented. In order to study the unsteady fluid behavior, the time domain is discretized, and an ALE base finite volume method is used to solve the NS equations. The aero-force is obtained and imposed on the platform. The equivalent point method is validated through commercial software RECURDYN. The results show that the equivalent point method can well represent the slack-taut cases of the sling system. It can also be found that the laminar flow model is used to describe the acting force of fluid on plate well at low Reynolds number. Finally, the comparisons are made between the steady and unsteady FSI models. The time history of unsteady fluid force displays severe oscillation while the steady fluid force varies evenly.